diff --git a/keyserver/src/responders/website-responders.js b/keyserver/src/responders/website-responders.js
index 4a0b99e99..9c9358e79 100644
--- a/keyserver/src/responders/website-responders.js
+++ b/keyserver/src/responders/website-responders.js
@@ -1,383 +1,383 @@
 // @flow
 
 import html from 'common-tags/lib/html';
 import type { $Response, $Request } from 'express';
 import fs from 'fs';
 import _keyBy from 'lodash/fp/keyBy';
 import * as React from 'react';
 import ReactDOMServer from 'react-dom/server';
 import { Provider } from 'react-redux';
 import { Route, StaticRouter } from 'react-router';
 import { createStore, type Store } from 'redux';
 import { promisify } from 'util';
 
 import { daysToEntriesFromEntryInfos } from 'lib/reducers/entry-reducer';
 import { freshMessageStore } from 'lib/reducers/message-reducer';
 import { mostRecentlyReadThread } from 'lib/selectors/thread-selectors';
 import { mostRecentMessageTimestamp } from 'lib/shared/message-utils';
 import {
   threadHasPermission,
   threadIsPending,
-  parseLocallyUniqueThreadID,
+  parsePendingThreadID,
   createPendingThread,
 } from 'lib/shared/thread-utils';
 import { defaultWebEnabledApps } from 'lib/types/enabled-apps';
 import { defaultCalendarFilters } from 'lib/types/filter-types';
 import { defaultNumberPerThread } from 'lib/types/message-types';
 import { defaultEnabledReports } from 'lib/types/report-types';
 import { defaultConnectionInfo } from 'lib/types/socket-types';
 import { threadPermissions, threadTypes } from 'lib/types/thread-types';
 import type { CurrentUserInfo } from 'lib/types/user-types';
 import { currentDateInTimeZone } from 'lib/utils/date-utils';
 import { ServerError } from 'lib/utils/errors';
 import { promiseAll } from 'lib/utils/promises';
 import { reducer } from 'web/redux/redux-setup';
 import type { AppState, Action } from 'web/redux/redux-setup';
 import getTitle from 'web/title/getTitle';
 import { navInfoFromURL } from 'web/url-utils';
 
 import { fetchEntryInfos } from '../fetchers/entry-fetchers';
 import { fetchMessageInfos } from '../fetchers/message-fetchers';
 import { fetchThreadInfos } from '../fetchers/thread-fetchers';
 import {
   fetchCurrentUserInfo,
   fetchKnownUserInfos,
 } from '../fetchers/user-fetchers';
 import { setNewSession } from '../session/cookies';
 import { Viewer } from '../session/viewer';
 import { streamJSON, waitForStream } from '../utils/json-stream';
 import {
   getAppURLFactsFromRequestURL,
   clientPathFromRouterPath,
 } from '../utils/urls';
 
 const { renderToNodeStream } = ReactDOMServer;
 
 const access = promisify(fs.access);
 const googleFontsURL =
   'https://fonts.googleapis.com/css2?family=IBM+Plex+Sans:wght@400;500;600&family=Inter:wght@400;500;600&display=swap';
 const localFontsURL = 'fonts/local-fonts.css';
 async function getFontsURL() {
   try {
     await access(localFontsURL);
     return localFontsURL;
   } catch {
     return googleFontsURL;
   }
 }
 
 type AssetInfo = { jsURL: string, fontsURL: string, cssInclude: string };
 let assetInfo: ?AssetInfo = null;
 async function getAssetInfo() {
   if (assetInfo) {
     return assetInfo;
   }
   if (process.env.NODE_ENV === 'development') {
     const fontsURL = await getFontsURL();
     assetInfo = {
       jsURL: 'http://localhost:8080/dev.build.js',
       fontsURL,
       cssInclude: '',
     };
     return assetInfo;
   }
   // $FlowFixMe web/dist doesn't always exist
   const { default: assets } = await import('web/dist/assets');
   assetInfo = {
     jsURL: `compiled/${assets.browser.js}`,
     fontsURL: googleFontsURL,
     cssInclude: html`
       <link
         rel="stylesheet"
         type="text/css"
         href="compiled/${assets.browser.css}"
       />
     `,
   };
   return assetInfo;
 }
 
 let webpackCompiledRootComponent: ?React.ComponentType<{}> = null;
 async function getWebpackCompiledRootComponentForSSR() {
   if (webpackCompiledRootComponent) {
     return webpackCompiledRootComponent;
   }
   try {
     // $FlowFixMe web/dist doesn't always exist
     const webpackBuild = await import('web/dist/app.build.cjs');
     webpackCompiledRootComponent = webpackBuild.default.default;
     return webpackCompiledRootComponent;
   } catch {
     throw new Error(
       'Could not load app.build.cjs. ' +
         'Did you forget to run `yarn dev` in the web folder?',
     );
   }
 }
 
 async function websiteResponder(
   viewer: Viewer,
   req: $Request,
   res: $Response,
 ): Promise<void> {
   const appURLFacts = getAppURLFactsFromRequestURL(req.originalUrl);
   const { basePath, baseDomain } = appURLFacts;
   const baseURL = basePath.replace(/\/$/, '');
   const baseHref = baseDomain + baseURL;
 
   const appPromise = getWebpackCompiledRootComponentForSSR();
 
   let initialNavInfo;
   try {
     initialNavInfo = navInfoFromURL(req.url, {
       now: currentDateInTimeZone(viewer.timeZone),
     });
   } catch (e) {
     throw new ServerError(e.message);
   }
 
   const calendarQuery = {
     startDate: initialNavInfo.startDate,
     endDate: initialNavInfo.endDate,
     filters: defaultCalendarFilters,
   };
   const messageSelectionCriteria = { joinedThreads: true };
   const initialTime = Date.now();
 
   const assetInfoPromise = getAssetInfo();
   const threadInfoPromise = fetchThreadInfos(viewer);
   const messageInfoPromise = fetchMessageInfos(
     viewer,
     messageSelectionCriteria,
     defaultNumberPerThread,
   );
   const entryInfoPromise = fetchEntryInfos(viewer, [calendarQuery]);
   const currentUserInfoPromise = fetchCurrentUserInfo(viewer);
   const userInfoPromise = fetchKnownUserInfos(viewer);
 
   const sessionIDPromise = (async () => {
     if (viewer.loggedIn) {
       await setNewSession(viewer, calendarQuery, initialTime);
     }
     return viewer.sessionID;
   })();
 
   const threadStorePromise = (async () => {
     const { threadInfos } = await threadInfoPromise;
     return { threadInfos };
   })();
   const messageStorePromise = (async () => {
     const [
       { threadInfos },
       { rawMessageInfos, truncationStatuses },
     ] = await Promise.all([threadInfoPromise, messageInfoPromise]);
     const { messageStore: freshStore } = freshMessageStore(
       rawMessageInfos,
       truncationStatuses,
       mostRecentMessageTimestamp(rawMessageInfos, initialTime),
       threadInfos,
     );
     return freshStore;
   })();
   const entryStorePromise = (async () => {
     const { rawEntryInfos } = await entryInfoPromise;
     return {
       entryInfos: _keyBy('id')(rawEntryInfos),
       daysToEntries: daysToEntriesFromEntryInfos(rawEntryInfos),
       lastUserInteractionCalendar: initialTime,
     };
   })();
   const userStorePromise = (async () => {
     const userInfos = await userInfoPromise;
     return { userInfos, inconsistencyReports: [] };
   })();
 
   const navInfoPromise = (async () => {
     const [
       { threadInfos },
       messageStore,
       currentUserInfo,
       userStore,
     ] = await Promise.all([
       threadInfoPromise,
       messageStorePromise,
       currentUserInfoPromise,
       userStorePromise,
     ]);
     const finalNavInfo = initialNavInfo;
 
     const requestedActiveChatThreadID = finalNavInfo.activeChatThreadID;
     if (
       requestedActiveChatThreadID &&
       !threadIsPending(requestedActiveChatThreadID) &&
       !threadHasPermission(
         threadInfos[requestedActiveChatThreadID],
         threadPermissions.VISIBLE,
       )
     ) {
       finalNavInfo.activeChatThreadID = null;
     }
 
     if (!finalNavInfo.activeChatThreadID) {
       const mostRecentThread = mostRecentlyReadThread(
         messageStore,
         threadInfos,
       );
       if (mostRecentThread) {
         finalNavInfo.activeChatThreadID = mostRecentThread;
       }
     }
 
     if (
       finalNavInfo.activeChatThreadID &&
       threadIsPending(finalNavInfo.activeChatThreadID) &&
       finalNavInfo.pendingThread?.id !== finalNavInfo.activeChatThreadID
     ) {
-      const pendingThreadData = parseLocallyUniqueThreadID(
+      const pendingThreadData = parsePendingThreadID(
         finalNavInfo.activeChatThreadID,
       );
       if (
         pendingThreadData &&
         pendingThreadData.threadType !== threadTypes.SIDEBAR &&
         currentUserInfo.id
       ) {
         const { userInfos } = userStore;
         const members = pendingThreadData.memberIDs
           .map(id => userInfos[id])
           .filter(Boolean);
         const newPendingThread = createPendingThread({
           viewerID: currentUserInfo.id,
           threadType: pendingThreadData.threadType,
           members,
         });
         finalNavInfo.activeChatThreadID = newPendingThread.id;
         finalNavInfo.pendingThread = newPendingThread;
       }
     }
 
     return finalNavInfo;
   })();
 
   const { jsURL, fontsURL, cssInclude } = await assetInfoPromise;
 
   // prettier-ignore
   res.write(html`
     <!DOCTYPE html>
     <html lang="en">
       <head>
         <meta charset="utf-8" />
         <title>${getTitle(0)}</title>
         <base href="${basePath}" />
         <link rel="stylesheet" type="text/css" href="${fontsURL}" />
         ${cssInclude}
         <link
           rel="apple-touch-icon"
           sizes="180x180"
           href="apple-touch-icon.png"
         />
         <link
           rel="icon"
           type="image/png"
           sizes="32x32"
           href="favicon-32x32.png"
         />
         <link
           rel="icon"
           type="image/png"
           sizes="16x16"
           href="favicon-16x16.png"
         />
         <link rel="manifest" href="site.webmanifest" />
         <meta name="apple-mobile-web-app-title" content="Comm" />
         <meta name="application-name" content="Comm" />
         <meta name="msapplication-TileColor" content="#b91d47" />
         <meta name="theme-color" content="#b91d47" />
       </head>
       <body>
         <div id="react-root">
   `);
 
   const statePromises = {
     navInfo: navInfoPromise,
     currentUserInfo: ((currentUserInfoPromise: any): Promise<CurrentUserInfo>),
     sessionID: sessionIDPromise,
     entryStore: entryStorePromise,
     threadStore: threadStorePromise,
     userStore: userStorePromise,
     messageStore: messageStorePromise,
     updatesCurrentAsOf: initialTime,
     loadingStatuses: {},
     calendarFilters: defaultCalendarFilters,
     // We can use paths local to the <base href> on web
     urlPrefix: '',
     windowDimensions: { width: 0, height: 0 },
     baseHref,
     connection: {
       ...defaultConnectionInfo('web', viewer.timeZone),
       actualizedCalendarQuery: calendarQuery,
     },
     watchedThreadIDs: [],
     lifecycleState: 'active',
     enabledApps: defaultWebEnabledApps,
     reportStore: {
       enabledReports: defaultEnabledReports,
       queuedReports: [],
     },
     nextLocalID: 0,
     timeZone: viewer.timeZone,
     userAgent: viewer.userAgent,
     cookie: undefined,
     deviceToken: undefined,
     dataLoaded: viewer.loggedIn,
     windowActive: true,
   };
 
   const [stateResult, App] = await Promise.all([
     promiseAll(statePromises),
     appPromise,
   ]);
   const state: AppState = { ...stateResult };
   const store: Store<AppState, Action> = createStore(reducer, state);
 
   const routerContext = {};
   const clientPath = clientPathFromRouterPath(req.url, appURLFacts);
   const reactStream = renderToNodeStream(
     <Provider store={store}>
       <StaticRouter
         location={clientPath}
         basename={baseURL}
         context={routerContext}
       >
         <Route path="*" component={App} />
       </StaticRouter>
     </Provider>,
   );
   if (routerContext.url) {
     throw new ServerError('URL modified during server render!');
   }
   reactStream.pipe(res, { end: false });
   await waitForStream(reactStream);
   res.write(html`
     </div>
     <script>
       var preloadedState =
   `);
 
   const filteredStatePromises = {
     ...statePromises,
     timeZone: null,
     userAgent: null,
   };
   const jsonStream = streamJSON(res, filteredStatePromises);
   await waitForStream(jsonStream);
   res.end(html`
     ;
           var baseURL = "${baseURL}";
         </script>
         <script src="${jsURL}"></script>
       </body>
     </html>
   `);
 }
 
 export { websiteResponder };
diff --git a/lib/reducers/message-reducer.js b/lib/reducers/message-reducer.js
index c38bc61c1..32b51d3ce 100644
--- a/lib/reducers/message-reducer.js
+++ b/lib/reducers/message-reducer.js
@@ -1,1414 +1,1412 @@
 // @flow
 
 import invariant from 'invariant';
 import _difference from 'lodash/fp/difference';
 import _flow from 'lodash/fp/flow';
 import _isEqual from 'lodash/fp/isEqual';
 import _keyBy from 'lodash/fp/keyBy';
 import _map from 'lodash/fp/map';
 import _mapKeys from 'lodash/fp/mapKeys';
 import _mapValues from 'lodash/fp/mapValues';
 import _omit from 'lodash/fp/omit';
 import _omitBy from 'lodash/fp/omitBy';
 import _pick from 'lodash/fp/pick';
 import _pickBy from 'lodash/fp/pickBy';
 import _uniq from 'lodash/fp/uniq';
 
 import {
   createEntryActionTypes,
   saveEntryActionTypes,
   deleteEntryActionTypes,
   restoreEntryActionTypes,
 } from '../actions/entry-actions';
 import {
   fetchMessagesBeforeCursorActionTypes,
   fetchMostRecentMessagesActionTypes,
   sendTextMessageActionTypes,
   sendMultimediaMessageActionTypes,
   saveMessagesActionType,
   processMessagesActionType,
   messageStorePruneActionType,
   createLocalMessageActionType,
   fetchSingleMostRecentMessagesFromThreadsActionTypes,
   setMessageStoreMessages,
 } from '../actions/message-actions';
 import {
   changeThreadSettingsActionTypes,
   deleteThreadActionTypes,
   leaveThreadActionTypes,
   newThreadActionTypes,
   removeUsersFromThreadActionTypes,
   changeThreadMemberRolesActionTypes,
   joinThreadActionTypes,
 } from '../actions/thread-actions';
 import { updateMultimediaMessageMediaActionType } from '../actions/upload-actions';
 import {
   logOutActionTypes,
   deleteAccountActionTypes,
   logInActionTypes,
   registerActionTypes,
 } from '../actions/user-actions';
-import { locallyUniqueToRealizedThreadIDsSelector } from '../selectors/thread-selectors';
+import { pendingToRealizedThreadIDsSelector } from '../selectors/thread-selectors';
 import {
   messageID,
   combineTruncationStatuses,
   sortMessageInfoList,
   sortMessageIDs,
   mergeThreadMessageInfos,
 } from '../shared/message-utils';
 import {
   threadHasPermission,
   threadInChatList,
   threadIsPending,
 } from '../shared/thread-utils';
 import threadWatcher from '../shared/thread-watcher';
 import { unshimMessageInfos } from '../shared/unshim-utils';
 import type { Media, Image } from '../types/media-types';
 import {
   type RawMessageInfo,
   type LocalMessageInfo,
   type MessageStore,
   type ReplaceMessageOperation,
   type MessageStoreOperation,
   type MessageTruncationStatus,
   type ThreadMessageInfo,
   type MessageTruncationStatuses,
   messageTruncationStatus,
   messageTypes,
   defaultNumberPerThread,
 } from '../types/message-types';
 import type { RawImagesMessageInfo } from '../types/messages/images';
 import type { RawMediaMessageInfo } from '../types/messages/media';
 import { type BaseAction } from '../types/redux-types';
 import { processServerRequestsActionType } from '../types/request-types';
 import {
   fullStateSyncActionType,
   incrementalStateSyncActionType,
 } from '../types/socket-types';
 import { type RawThreadInfo, threadPermissions } from '../types/thread-types';
 import {
   updateTypes,
   type ClientUpdateInfo,
   processUpdatesActionType,
 } from '../types/update-types';
 import { setNewSessionActionType } from '../utils/action-utils';
 import { translateClientDBMessageInfosToRawMessageInfos } from '../utils/message-ops-utils';
 
 const _mapValuesWithKeys = _mapValues.convert({ cap: false });
 
 // Input must already be ordered!
 function mapThreadsToMessageIDsFromOrderedMessageInfos(
   orderedMessageInfos: $ReadOnlyArray<RawMessageInfo>,
 ): { [threadID: string]: string[] } {
   const threadsToMessageIDs: { [threadID: string]: string[] } = {};
   for (const messageInfo of orderedMessageInfos) {
     const key = messageID(messageInfo);
     if (!threadsToMessageIDs[messageInfo.threadID]) {
       threadsToMessageIDs[messageInfo.threadID] = [key];
     } else {
       threadsToMessageIDs[messageInfo.threadID].push(key);
     }
   }
   return threadsToMessageIDs;
 }
 
 function isThreadWatched(
   threadID: string,
   threadInfo: ?RawThreadInfo,
   watchedIDs: $ReadOnlyArray<string>,
 ) {
   return (
     threadIsPending(threadID) ||
     (threadInfo &&
       threadHasPermission(threadInfo, threadPermissions.VISIBLE) &&
       (threadInChatList(threadInfo) || watchedIDs.includes(threadID)))
   );
 }
 
 type FreshMessageStoreResult = {
   +messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
   +messageStore: MessageStore,
 };
 function freshMessageStore(
   messageInfos: $ReadOnlyArray<RawMessageInfo>,
   truncationStatus: { [threadID: string]: MessageTruncationStatus },
   currentAsOf: number,
   threadInfos: { +[threadID: string]: RawThreadInfo },
 ): FreshMessageStoreResult {
   const unshimmed = unshimMessageInfos(messageInfos);
   const orderedMessageInfos = sortMessageInfoList(unshimmed);
   const messages = _keyBy(messageID)(orderedMessageInfos);
 
   const messageStoreOperations = orderedMessageInfos.map(messageInfo => ({
     type: 'replace',
     payload: { id: messageID(messageInfo), messageInfo },
   }));
 
   const threadsToMessageIDs = mapThreadsToMessageIDsFromOrderedMessageInfos(
     orderedMessageInfos,
   );
   const lastPruned = Date.now();
   const threads = _mapValuesWithKeys(
     (messageIDs: string[], threadID: string) => ({
       messageIDs,
       startReached:
         truncationStatus[threadID] === messageTruncationStatus.EXHAUSTIVE,
       lastNavigatedTo: 0,
       lastPruned,
     }),
   )(threadsToMessageIDs);
   const watchedIDs = threadWatcher.getWatchedIDs();
   for (const threadID in threadInfos) {
     const threadInfo = threadInfos[threadID];
     if (
       threads[threadID] ||
       !isThreadWatched(threadID, threadInfo, watchedIDs)
     ) {
       continue;
     }
     threads[threadID] = {
       messageIDs: [],
       startReached: false,
       lastNavigatedTo: 0,
       lastPruned,
     };
   }
   return {
     messageStoreOperations,
     messageStore: { messages, threads, local: {}, currentAsOf },
   };
 }
 
 type ReassignmentResult = {
   +messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
   +messageStore: MessageStore,
   +reassignedThreadIDs: $ReadOnlyArray<string>,
 };
 
 function reassignMessagesToRealizedThreads(
   messageStore: MessageStore,
   threadInfos: { +[threadID: string]: RawThreadInfo },
 ): ReassignmentResult {
-  const locallyUniqueToRealizedThreadIDs = locallyUniqueToRealizedThreadIDsSelector(
+  const pendingToRealizedThreadIDs = pendingToRealizedThreadIDsSelector(
     threadInfos,
   );
 
   const messageStoreOperations: MessageStoreOperation[] = [];
   const messages = {};
   for (const storeMessageID in messageStore.messages) {
     const message = messageStore.messages[storeMessageID];
-    const newThreadID = locallyUniqueToRealizedThreadIDs.get(message.threadID);
+    const newThreadID = pendingToRealizedThreadIDs.get(message.threadID);
 
     messages[storeMessageID] = newThreadID
       ? {
           ...message,
           threadID: newThreadID,
           time: threadInfos[newThreadID]?.creationTime ?? message.time,
         }
       : message;
 
     if (!newThreadID) {
       continue;
     }
 
     const updateMsgOperation: ReplaceMessageOperation = {
       type: 'replace',
       payload: { id: storeMessageID, messageInfo: messages[storeMessageID] },
     };
 
     messageStoreOperations.push(updateMsgOperation);
   }
 
   const threads = {};
   const reassignedThreadIDs = [];
   for (const threadID in messageStore.threads) {
     const threadMessageInfo = messageStore.threads[threadID];
-    const newThreadID = locallyUniqueToRealizedThreadIDs.get(threadID);
+    const newThreadID = pendingToRealizedThreadIDs.get(threadID);
     if (!newThreadID) {
       threads[threadID] = threadMessageInfo;
       continue;
     }
     const realizedThread = messageStore.threads[newThreadID];
     if (!realizedThread) {
       reassignedThreadIDs.push(newThreadID);
       threads[newThreadID] = threadMessageInfo;
       continue;
     }
     threads[newThreadID] = mergeThreadMessageInfos(
       threadMessageInfo,
       realizedThread,
       messages,
     );
   }
 
   return {
     messageStoreOperations,
     messageStore: {
       ...messageStore,
       threads,
       messages,
     },
     reassignedThreadIDs,
   };
 }
 
 type MergeNewMessagesResult = {
   +messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
   +messageStore: MessageStore,
 };
 // oldMessageStore is from the old state
 // newMessageInfos, truncationStatus come from server
 function mergeNewMessages(
   oldMessageStore: MessageStore,
   newMessageInfos: $ReadOnlyArray<RawMessageInfo>,
   truncationStatus: { [threadID: string]: MessageTruncationStatus },
   threadInfos: { +[threadID: string]: RawThreadInfo },
 ): MergeNewMessagesResult {
   const {
     messageStoreOperations: updateWithLatestThreadInfosOps,
     messageStore: messageStoreUpdatedWithLatestThreadInfos,
     reassignedThreadIDs,
   } = updateMessageStoreWithLatestThreadInfos(oldMessageStore, threadInfos);
 
   const messageStoreAfterUpdateOps = processMessageStoreOperations(
     oldMessageStore,
     updateWithLatestThreadInfosOps,
   );
 
   const updatedMessageStore = {
     ...messageStoreUpdatedWithLatestThreadInfos,
     messages: messageStoreAfterUpdateOps.messages,
   };
 
   const localIDsToServerIDs: Map<string, string> = new Map();
 
   const watchedThreadIDs = [
     ...threadWatcher.getWatchedIDs(),
     ...reassignedThreadIDs,
   ];
   const unshimmedNewMessages = unshimMessageInfos(newMessageInfos);
   const unshimmedNewMessagesOfWatchedThreads = unshimmedNewMessages.filter(
     msg =>
       isThreadWatched(
         msg.threadID,
         threadInfos[msg.threadID],
         watchedThreadIDs,
       ),
   );
   const orderedNewMessageInfos = _flow(
     _map((messageInfo: RawMessageInfo) => {
       const { id: inputID } = messageInfo;
       invariant(inputID, 'new messageInfos should have serverID');
       invariant(
         !threadIsPending(messageInfo.threadID),
         'new messageInfos should have realized thread id',
       );
       const currentMessageInfo = updatedMessageStore.messages[inputID];
       if (
         messageInfo.type === messageTypes.TEXT ||
         messageInfo.type === messageTypes.IMAGES ||
         messageInfo.type === messageTypes.MULTIMEDIA
       ) {
         const { localID: inputLocalID } = messageInfo;
         const currentLocalMessageInfo = inputLocalID
           ? updatedMessageStore.messages[inputLocalID]
           : null;
         if (currentMessageInfo && currentMessageInfo.localID) {
           // If the client already has a RawMessageInfo with this serverID, keep
           // any localID associated with the existing one. This is because we
           // use localIDs as React keys and changing React keys leads to loss of
           // component state. (The conditional below is for Flow)
           if (messageInfo.type === messageTypes.TEXT) {
             messageInfo = {
               ...messageInfo,
               localID: currentMessageInfo.localID,
             };
           } else if (messageInfo.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({
               ...messageInfo,
               localID: currentMessageInfo.localID,
             }: RawMediaMessageInfo);
           } else {
             messageInfo = ({
               ...messageInfo,
               localID: currentMessageInfo.localID,
             }: RawImagesMessageInfo);
           }
         } else if (currentLocalMessageInfo && currentLocalMessageInfo.localID) {
           // If the client has a RawMessageInfo with this localID, but not with
           // the serverID, that means the message creation succeeded but the
           // success action never got processed. We set a key in
           // localIDsToServerIDs here to fix the messageIDs for the rest of the
           // MessageStore too. (The conditional below is for Flow)
           invariant(inputLocalID, 'inputLocalID should be set');
           localIDsToServerIDs.set(inputLocalID, inputID);
           if (messageInfo.type === messageTypes.TEXT) {
             messageInfo = {
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             };
           } else if (messageInfo.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             }: RawMediaMessageInfo);
           } else {
             messageInfo = ({
               ...messageInfo,
               localID: currentLocalMessageInfo.localID,
             }: RawImagesMessageInfo);
           }
         } else {
           // If neither the serverID nor the localID from the delivered
           // RawMessageInfo exists in the client store, then this message is
           // brand new to us. Ignore any localID provided by the server.
           // (The conditional below is for Flow)
           const { localID, ...rest } = messageInfo;
           if (rest.type === messageTypes.TEXT) {
             messageInfo = { ...rest };
           } else if (rest.type === messageTypes.MULTIMEDIA) {
             messageInfo = ({ ...rest }: RawMediaMessageInfo);
           } else {
             messageInfo = ({ ...rest }: RawImagesMessageInfo);
           }
         }
       } else if (
         currentMessageInfo &&
         messageInfo.time > currentMessageInfo.time
       ) {
         // When thick threads will be introduced it will be possible for two
         // clients to create the same message (e.g. when they create the same
         // sidebar at the same time). We're going to use deterministic ids for
         // messages which should be unique within a thread and we have to find
         // a way for clients to agree which message to keep. We can't rely on
         // always choosing incoming messages nor messages from the store,
         // because a message that is in one user's store, will be send to
         // another user. One way to deal with it is to always choose a message
         // which is older, according to its timestamp. We can use this strategy
         // only for messages that can start a thread, because for other types
         // it might break the "contiguous" property of message ids (we can
         // consider selecting younger messages in that case, but for now we use
         // an invariant).
         invariant(
           messageInfo.type === messageTypes.CREATE_SIDEBAR ||
             messageInfo.type === messageTypes.CREATE_THREAD ||
             messageInfo.type === messageTypes.SIDEBAR_SOURCE,
           `Two different messages of type ${messageInfo.type} with the same ` +
             'id found',
         );
         return currentMessageInfo;
       }
       return _isEqual(messageInfo)(currentMessageInfo)
         ? currentMessageInfo
         : messageInfo;
     }),
     sortMessageInfoList,
   )(unshimmedNewMessagesOfWatchedThreads);
 
   const newMessageOps: MessageStoreOperation[] = [];
   const threadsToMessageIDs = mapThreadsToMessageIDsFromOrderedMessageInfos(
     orderedNewMessageInfos,
   );
   const oldMessageInfosToCombine = [];
   const threadsThatNeedMessageIDsResorted = [];
   const lastPruned = Date.now();
   const local = {};
   const threads = _flow(
     _mapValuesWithKeys((messageIDs: string[], threadID: string) => {
       const oldThread = updatedMessageStore.threads[threadID];
       const truncate = truncationStatus[threadID];
       if (!oldThread) {
         return {
           messageIDs,
           startReached: truncate === messageTruncationStatus.EXHAUSTIVE,
           lastNavigatedTo: 0,
           lastPruned,
         };
       }
       let oldMessageIDsUnchanged = true;
       const oldMessageIDs = oldThread.messageIDs.map(oldID => {
         const newID = localIDsToServerIDs.get(oldID);
         if (newID !== null && newID !== undefined) {
           oldMessageIDsUnchanged = false;
           return newID;
         }
         return oldID;
       });
       if (truncate === messageTruncationStatus.TRUNCATED) {
         // If the result set in the payload isn't contiguous with what we have
         // now, that means we need to dump what we have in the state and replace
         // it with the result set. We do this to achieve our two goals for the
         // messageStore: currentness and contiguousness.
         newMessageOps.push({
           type: 'remove_messages_for_threads',
           payload: { threadIDs: [threadID] },
         });
         return {
           messageIDs,
           startReached: false,
           lastNavigatedTo: oldThread.lastNavigatedTo,
           lastPruned: oldThread.lastPruned,
         };
       }
       const oldNotInNew = _difference(oldMessageIDs)(messageIDs);
       for (const id of oldNotInNew) {
         const oldMessageInfo = updatedMessageStore.messages[id];
         invariant(oldMessageInfo, `could not find ${id} in messageStore`);
         oldMessageInfosToCombine.push(oldMessageInfo);
         const localInfo = updatedMessageStore.local[id];
         if (localInfo) {
           local[id] = localInfo;
         }
       }
       const startReached =
         oldThread.startReached ||
         truncate === messageTruncationStatus.EXHAUSTIVE;
       if (_difference(messageIDs)(oldMessageIDs).length === 0) {
         if (startReached === oldThread.startReached && oldMessageIDsUnchanged) {
           return oldThread;
         }
         return {
           messageIDs: oldMessageIDs,
           startReached,
           lastNavigatedTo: oldThread.lastNavigatedTo,
           lastPruned: oldThread.lastPruned,
         };
       }
       const mergedMessageIDs = [...messageIDs, ...oldNotInNew];
       threadsThatNeedMessageIDsResorted.push(threadID);
       return {
         messageIDs: mergedMessageIDs,
         startReached,
         lastNavigatedTo: oldThread.lastNavigatedTo,
         lastPruned: oldThread.lastPruned,
       };
     }),
     _pickBy(thread => !!thread),
   )(threadsToMessageIDs);
 
   for (const threadID in updatedMessageStore.threads) {
     if (threads[threadID]) {
       continue;
     }
     let thread = updatedMessageStore.threads[threadID];
     const truncate = truncationStatus[threadID];
     if (truncate === messageTruncationStatus.EXHAUSTIVE) {
       thread = {
         ...thread,
         startReached: true,
       };
     }
     threads[threadID] = thread;
     for (const id of thread.messageIDs) {
       const messageInfo = updatedMessageStore.messages[id];
       if (messageInfo) {
         oldMessageInfosToCombine.push(messageInfo);
       }
       const localInfo = updatedMessageStore.local[id];
       if (localInfo) {
         local[id] = localInfo;
       }
     }
   }
 
   const messages = _flow(
     sortMessageInfoList,
     _keyBy(messageID),
   )([...orderedNewMessageInfos, ...oldMessageInfosToCombine]);
 
   const newMessages = _keyBy(messageID)(orderedNewMessageInfos);
   for (const id in newMessages) {
     newMessageOps.push({
       type: 'replace',
       payload: { id, messageInfo: newMessages[id] },
     });
   }
 
   if (localIDsToServerIDs.size > 0) {
     newMessageOps.push({
       type: 'remove',
       payload: { ids: [...localIDsToServerIDs.keys()] },
     });
   }
 
   for (const threadID of threadsThatNeedMessageIDsResorted) {
     threads[threadID].messageIDs = sortMessageIDs(messages)(
       threads[threadID].messageIDs,
     );
   }
 
   const currentAsOf = Math.max(
     orderedNewMessageInfos.length > 0 ? orderedNewMessageInfos[0].time : 0,
     updatedMessageStore.currentAsOf,
   );
 
   const processedMessageStore = processMessageStoreOperations(
     updatedMessageStore,
     newMessageOps,
   );
 
   return {
     messageStoreOperations: [
       ...updateWithLatestThreadInfosOps,
       ...newMessageOps,
     ],
     messageStore: {
       messages: processedMessageStore.messages,
       threads,
       local,
       currentAsOf,
     },
   };
 }
 
 type UpdateMessageStoreWithLatestThreadInfosResult = {
   +messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
   +messageStore: MessageStore,
   +reassignedThreadIDs: $ReadOnlyArray<string>,
 };
 function updateMessageStoreWithLatestThreadInfos(
   messageStore: MessageStore,
   threadInfos: { +[id: string]: RawThreadInfo },
 ): UpdateMessageStoreWithLatestThreadInfosResult {
   const messageStoreOperations: MessageStoreOperation[] = [];
   const {
     messageStore: reassignedMessageStore,
     messageStoreOperations: reassignMessagesOps,
     reassignedThreadIDs,
   } = reassignMessagesToRealizedThreads(messageStore, threadInfos);
   messageStoreOperations.push(...reassignMessagesOps);
   const watchedIDs = [...threadWatcher.getWatchedIDs(), ...reassignedThreadIDs];
   const watchedThreadInfos = _pickBy((threadInfo: RawThreadInfo) =>
     isThreadWatched(threadInfo.id, threadInfo, watchedIDs),
   )(threadInfos);
 
   const filteredThreads = _pick(Object.keys(watchedThreadInfos))(
     reassignedMessageStore.threads,
   );
 
   const messageIDsToRemove = [];
   const threadsToRemoveMessagesFrom = [];
   for (const threadID in reassignedMessageStore.threads) {
     if (watchedThreadInfos[threadID]) {
       continue;
     }
     threadsToRemoveMessagesFrom.push(threadID);
     for (const id of reassignedMessageStore.threads[threadID].messageIDs) {
       messageIDsToRemove.push(id);
     }
   }
 
   for (const threadID in threadInfos) {
     const threadInfo = threadInfos[threadID];
     if (
       isThreadWatched(threadID, threadInfo, watchedIDs) &&
       !filteredThreads[threadID]
     ) {
       filteredThreads[threadID] = {
         messageIDs: [],
         // We can conclude that startReached, since no messages were returned.
         startReached: true,
         lastNavigatedTo: 0,
         lastPruned: Date.now(),
       };
     }
   }
 
   messageStoreOperations.push({
     type: 'remove_messages_for_threads',
     payload: { threadIDs: threadsToRemoveMessagesFrom },
   });
 
   return {
     messageStoreOperations,
     messageStore: {
       messages: _omit(messageIDsToRemove)(reassignedMessageStore.messages),
       threads: filteredThreads,
       local: _omit(messageIDsToRemove)(reassignedMessageStore.local),
       currentAsOf: reassignedMessageStore.currentAsOf,
     },
     reassignedThreadIDs,
   };
 }
 
 function ensureRealizedThreadIDIsUsedWhenPossible<T: RawMessageInfo>(
   payload: T,
   threadInfos: { +[id: string]: RawThreadInfo },
 ): T {
-  const locallyUniqueToRealizedThreadIDs = locallyUniqueToRealizedThreadIDsSelector(
+  const pendingToRealizedThreadIDs = pendingToRealizedThreadIDsSelector(
     threadInfos,
   );
-  const realizedThreadID = locallyUniqueToRealizedThreadIDs.get(
-    payload.threadID,
-  );
+  const realizedThreadID = pendingToRealizedThreadIDs.get(payload.threadID);
   return realizedThreadID
     ? { ...payload, threadID: realizedThreadID }
     : payload;
 }
 
 function processMessageStoreOperations(
   messageStore: MessageStore,
   messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
 ): MessageStore {
   if (messageStoreOperations.length === 0) {
     return messageStore;
   }
   let processedMessages = { ...messageStore.messages };
   for (const operation of messageStoreOperations) {
     if (operation.type === 'replace') {
       processedMessages[operation.payload.id] = operation.payload.messageInfo;
     } else if (operation.type === 'remove') {
       for (const id of operation.payload.ids) {
         delete processedMessages[id];
       }
     } else if (operation.type === 'remove_messages_for_threads') {
       for (const msgID in processedMessages) {
         if (
           operation.payload.threadIDs.includes(
             processedMessages[msgID].threadID,
           )
         ) {
           delete processedMessages[msgID];
         }
       }
     } else if (operation.type === 'rekey') {
       processedMessages[operation.payload.to] =
         processedMessages[operation.payload.from];
       delete processedMessages[operation.payload.from];
     } else if (operation.type === 'remove_all') {
       processedMessages = {};
     }
   }
   return { ...messageStore, messages: processedMessages };
 }
 
 type ReduceMessageStoreResult = {
   +messageStoreOperations: $ReadOnlyArray<MessageStoreOperation>,
   +messageStore: MessageStore,
 };
 function reduceMessageStore(
   messageStore: MessageStore,
   action: BaseAction,
   newThreadInfos: { +[id: string]: RawThreadInfo },
 ): ReduceMessageStoreResult {
   if (action.type === logInActionTypes.success) {
     const messagesResult = action.payload.messagesResult;
     const {
       messageStoreOperations,
       messageStore: freshStore,
     } = freshMessageStore(
       messagesResult.messageInfos,
       messagesResult.truncationStatus,
       messagesResult.currentAsOf,
       newThreadInfos,
     );
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: { ...freshStore, messages: processedMessageStore.messages },
     };
   } else if (action.type === incrementalStateSyncActionType) {
     if (
       action.payload.messagesResult.rawMessageInfos.length === 0 &&
       action.payload.updatesResult.newUpdates.length === 0
     ) {
       return { messageStoreOperations: [], messageStore };
     }
 
     const messagesResult = mergeUpdatesWithMessageInfos(
       action.payload.messagesResult.rawMessageInfos,
       action.payload.updatesResult.newUpdates,
       action.payload.messagesResult.truncationStatuses,
     );
 
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
     );
   } else if (action.type === processUpdatesActionType) {
     if (action.payload.updatesResult.newUpdates.length === 0) {
       return { messageStoreOperations: [], messageStore };
     }
 
     const messagesResult = mergeUpdatesWithMessageInfos(
       [],
       action.payload.updatesResult.newUpdates,
     );
 
     const {
       messageStoreOperations,
       messageStore: newMessageStore,
     } = mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
     );
     return {
       messageStoreOperations,
       messageStore: {
         messages: newMessageStore.messages,
         threads: newMessageStore.threads,
         local: newMessageStore.local,
         currentAsOf: messageStore.currentAsOf,
       },
     };
   } else if (
     action.type === fullStateSyncActionType ||
     action.type === processMessagesActionType
   ) {
     const { messagesResult } = action.payload;
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
     );
   } else if (
     action.type === fetchSingleMostRecentMessagesFromThreadsActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       action.payload.truncationStatuses,
       newThreadInfos,
     );
   } else if (
     action.type === fetchMessagesBeforeCursorActionTypes.success ||
     action.type === fetchMostRecentMessagesActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       { [action.payload.threadID]: action.payload.truncationStatus },
       newThreadInfos,
     );
   } else if (
     action.type === logOutActionTypes.success ||
     action.type === deleteAccountActionTypes.success ||
     action.type === deleteThreadActionTypes.success ||
     action.type === leaveThreadActionTypes.success ||
     action.type === setNewSessionActionType
   ) {
     const {
       messageStoreOperations,
       messageStore: filteredMessageStore,
     } = updateMessageStoreWithLatestThreadInfos(messageStore, newThreadInfos);
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...filteredMessageStore,
         messages: processedMessageStore.messages,
       },
     };
   } else if (action.type === newThreadActionTypes.success) {
     const messagesResult = mergeUpdatesWithMessageInfos(
       action.payload.newMessageInfos,
       action.payload.updatesResult.newUpdates,
     );
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
     );
   } else if (action.type === registerActionTypes.success) {
     const truncationStatuses = {};
     for (const messageInfo of action.payload.rawMessageInfos) {
       truncationStatuses[messageInfo.threadID] =
         messageTruncationStatus.EXHAUSTIVE;
     }
     return mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       truncationStatuses,
       newThreadInfos,
     );
   } else if (
     action.type === changeThreadSettingsActionTypes.success ||
     action.type === removeUsersFromThreadActionTypes.success ||
     action.type === changeThreadMemberRolesActionTypes.success ||
     action.type === createEntryActionTypes.success ||
     action.type === saveEntryActionTypes.success ||
     action.type === restoreEntryActionTypes.success
   ) {
     return mergeNewMessages(
       messageStore,
       action.payload.newMessageInfos,
       { [action.payload.threadID]: messageTruncationStatus.UNCHANGED },
       newThreadInfos,
     );
   } else if (action.type === deleteEntryActionTypes.success) {
     const payload = action.payload;
     if (payload) {
       return mergeNewMessages(
         messageStore,
         payload.newMessageInfos,
         { [payload.threadID]: messageTruncationStatus.UNCHANGED },
         newThreadInfos,
       );
     }
   } else if (action.type === joinThreadActionTypes.success) {
     const messagesResult = mergeUpdatesWithMessageInfos(
       action.payload.rawMessageInfos,
       action.payload.updatesResult.newUpdates,
     );
     return mergeNewMessages(
       messageStore,
       messagesResult.rawMessageInfos,
       messagesResult.truncationStatuses,
       newThreadInfos,
     );
   } else if (
     action.type === sendTextMessageActionTypes.started ||
     action.type === sendMultimediaMessageActionTypes.started
   ) {
     const payload = ensureRealizedThreadIDIsUsedWhenPossible(
       action.payload,
       newThreadInfos,
     );
     const { localID, threadID } = payload;
     invariant(localID, `localID should be set on ${action.type}`);
 
     const messageStoreOperations = [
       {
         type: 'replace',
         payload: { id: localID, messageInfo: payload },
       },
     ];
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     const now = Date.now();
     const messageIDs = messageStore.threads[threadID]?.messageIDs ?? [];
     if (messageStore.messages[localID]) {
       const messages = { ...messageStore.messages, [localID]: payload };
       const local = _pickBy(
         (localInfo: LocalMessageInfo, key: string) => key !== localID,
       )(messageStore.local);
       const thread = messageStore.threads[threadID];
       const threads = {
         ...messageStore.threads,
         [threadID]: {
           messageIDs: sortMessageIDs(messages)(messageIDs),
           startReached: thread?.startReached ?? true,
           lastNavigatedTo: thread?.lastNavigatedTo ?? now,
           lastPruned: thread?.lastPruned ?? now,
         },
       };
       return {
         messageStoreOperations,
         messageStore: {
           ...messageStore,
           messages: processedMessageStore.messages,
           threads,
           local,
         },
       };
     }
 
     for (const existingMessageID of messageIDs) {
       const existingMessageInfo = messageStore.messages[existingMessageID];
       if (existingMessageInfo && existingMessageInfo.localID === localID) {
         return { messageStoreOperations: [], messageStore };
       }
     }
 
     const threadState: ThreadMessageInfo = messageStore.threads[threadID]
       ? {
           ...messageStore.threads[threadID],
           messageIDs: [localID, ...messageIDs],
         }
       : {
           messageIDs: [localID],
           startReached: true,
           lastNavigatedTo: now,
           lastPruned: now,
         };
 
     return {
       messageStoreOperations,
       messageStore: {
         messages: processedMessageStore.messages,
         threads: {
           ...messageStore.threads,
           [threadID]: threadState,
         },
         local: messageStore.local,
         currentAsOf: messageStore.currentAsOf,
       },
     };
   } else if (
     action.type === sendTextMessageActionTypes.failed ||
     action.type === sendMultimediaMessageActionTypes.failed
   ) {
     const { localID } = action.payload;
     return {
       messageStoreOperations: [],
       messageStore: {
         messages: messageStore.messages,
         threads: messageStore.threads,
         local: {
           ...messageStore.local,
           [localID]: { sendFailed: true },
         },
         currentAsOf: messageStore.currentAsOf,
       },
     };
   } else if (
     action.type === sendTextMessageActionTypes.success ||
     action.type === sendMultimediaMessageActionTypes.success
   ) {
     const { payload } = action;
     invariant(
       !threadIsPending(payload.threadID),
       'Successful message action should have realized thread id',
     );
     const replaceMessageKey = (messageKey: string) =>
       messageKey === payload.localID ? payload.serverID : messageKey;
     let newMessages;
     const messageStoreOperations = [];
     if (messageStore.messages[payload.serverID]) {
       // If somehow the serverID got in there already, we'll just update the
       // serverID message and scrub the localID one
       newMessages = _omitBy(
         (messageInfo: RawMessageInfo) =>
           messageInfo.type === messageTypes.TEXT &&
           !messageInfo.id &&
           messageInfo.localID === payload.localID,
       )(messageStore.messages);
       messageStoreOperations.push({
         type: 'remove',
         payload: { ids: [payload.localID] },
       });
     } else if (messageStore.messages[payload.localID]) {
       // The normal case, the localID message gets replaced by the serverID one
       newMessages = _mapKeys(replaceMessageKey)(messageStore.messages);
       messageStoreOperations.push({
         type: 'rekey',
         payload: { from: payload.localID, to: payload.serverID },
       });
     } else {
       // Well this is weird, we probably got deauthorized between when the
       // action was dispatched and when we ran this reducer...
       return { messageStoreOperations, messageStore };
     }
 
     const newMessage = {
       ...newMessages[payload.serverID],
       id: payload.serverID,
       localID: payload.localID,
       time: payload.time,
     };
     newMessages[payload.serverID] = newMessage;
     messageStoreOperations.push({
       type: 'replace',
       payload: { id: payload.serverID, messageInfo: newMessage },
     });
     const threadID = payload.threadID;
     const newMessageIDs = _flow(
       _uniq,
       sortMessageIDs(newMessages),
     )(messageStore.threads[threadID].messageIDs.map(replaceMessageKey));
     const local = _pickBy(
       (localInfo: LocalMessageInfo, key: string) => key !== payload.localID,
     )(messageStore.local);
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...messageStore,
         messages: processedMessageStore.messages,
         threads: {
           ...messageStore.threads,
           [threadID]: {
             ...messageStore.threads[threadID],
             messageIDs: newMessageIDs,
           },
         },
         local,
       },
     };
   } else if (action.type === saveMessagesActionType) {
     const truncationStatuses = {};
     for (const messageInfo of action.payload.rawMessageInfos) {
       truncationStatuses[messageInfo.threadID] =
         messageTruncationStatus.UNCHANGED;
     }
     const {
       messageStoreOperations,
       messageStore: newMessageStore,
     } = mergeNewMessages(
       messageStore,
       action.payload.rawMessageInfos,
       truncationStatuses,
       newThreadInfos,
     );
     return {
       messageStoreOperations,
       messageStore: {
         messages: newMessageStore.messages,
         threads: newMessageStore.threads,
         local: newMessageStore.local,
         // We avoid bumping currentAsOf because notifs may include a contracted
         // RawMessageInfo, so we want to make sure we still fetch it
         currentAsOf: messageStore.currentAsOf,
       },
     };
   } else if (action.type === messageStorePruneActionType) {
     const now = Date.now();
     const messageIDsToPrune = [];
 
     const newThreads = { ...messageStore.threads };
     for (const threadID of action.payload.threadIDs) {
       let thread = newThreads[threadID];
       if (!thread) {
         continue;
       }
       thread = { ...thread, lastPruned: now };
 
       const newMessageIDs = [...thread.messageIDs];
       const removed = newMessageIDs.splice(defaultNumberPerThread);
       if (removed.length > 0) {
         thread = {
           ...thread,
           messageIDs: newMessageIDs,
           startReached: false,
         };
       }
       for (const id of removed) {
         messageIDsToPrune.push(id);
       }
 
       newThreads[threadID] = thread;
     }
 
     const messageStoreOperations = [
       {
         type: 'remove',
         payload: { ids: messageIDsToPrune },
       },
     ];
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         messages: processedMessageStore.messages,
         threads: newThreads,
         local: _omit(messageIDsToPrune)(messageStore.local),
         currentAsOf: messageStore.currentAsOf,
       },
     };
   } else if (action.type === updateMultimediaMessageMediaActionType) {
     const { messageID: id, currentMediaID, mediaUpdate } = action.payload;
     const message = messageStore.messages[id];
     invariant(message, `message with ID ${id} could not be found`);
     invariant(
       message.type === messageTypes.IMAGES ||
         message.type === messageTypes.MULTIMEDIA,
       `message with ID ${id} is not multimedia`,
     );
 
     let updatedMessage;
     let replaced = false;
     if (message.type === messageTypes.IMAGES) {
       const media: Image[] = [];
       for (const singleMedia of message.media) {
         if (singleMedia.id !== currentMediaID) {
           media.push(singleMedia);
         } else {
           let updatedMedia: Image = {
             id: mediaUpdate.id ?? singleMedia.id,
             type: 'photo',
             uri: mediaUpdate.uri ?? singleMedia.uri,
             dimensions: mediaUpdate.dimensions ?? singleMedia.dimensions,
           };
 
           if (
             'localMediaSelection' in singleMedia &&
             !('localMediaSelection' in mediaUpdate)
           ) {
             updatedMedia = {
               ...updatedMedia,
               localMediaSelection: singleMedia.localMediaSelection,
             };
           } else if (mediaUpdate.localMediaSelection) {
             updatedMedia = {
               ...updatedMedia,
               localMediaSelection: mediaUpdate.localMediaSelection,
             };
           }
 
           media.push(updatedMedia);
           replaced = true;
         }
       }
       updatedMessage = { ...message, media };
     } else {
       const media: Media[] = [];
       for (const singleMedia of message.media) {
         if (singleMedia.id !== currentMediaID) {
           media.push(singleMedia);
         } else if (
           singleMedia.type === 'photo' &&
           mediaUpdate.type === 'photo'
         ) {
           media.push({ ...singleMedia, ...mediaUpdate });
           replaced = true;
         } else if (
           singleMedia.type === 'video' &&
           mediaUpdate.type === 'video'
         ) {
           media.push({ ...singleMedia, ...mediaUpdate });
           replaced = true;
         }
       }
       updatedMessage = { ...message, media };
     }
 
     invariant(
       replaced,
       `message ${id} did not contain media with ID ${currentMediaID}`,
     );
 
     const messageStoreOperations = [
       {
         type: 'replace',
         payload: {
           id,
           messageInfo: updatedMessage,
         },
       },
     ];
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...messageStore,
         messages: processedMessageStore.messages,
       },
     };
   } else if (action.type === createLocalMessageActionType) {
     const messageInfo = ensureRealizedThreadIDIsUsedWhenPossible(
       action.payload,
       newThreadInfos,
     );
     const { localID, threadID } = messageInfo;
 
     const messageIDs =
       messageStore.threads[messageInfo.threadID]?.messageIDs ?? [];
     const now = Date.now();
     const threadState: ThreadMessageInfo = messageStore.threads[threadID]
       ? {
           ...messageStore.threads[threadID],
           messageIDs: [localID, ...messageIDs],
         }
       : {
           messageIDs: [localID],
           startReached: true,
           lastNavigatedTo: now,
           lastPruned: now,
         };
 
     const messageStoreOperations = [
       {
         type: 'replace',
         payload: { id: localID, messageInfo },
       },
     ];
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...messageStore,
         threads: {
           ...messageStore.threads,
           [threadID]: threadState,
         },
         messages: processedMessageStore.messages,
       },
     };
   } else if (action.type === processServerRequestsActionType) {
     const {
       messageStoreOperations,
       messageStore: messageStoreAfterReassignment,
     } = reassignMessagesToRealizedThreads(messageStore, newThreadInfos);
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...messageStoreAfterReassignment,
         messages: processedMessageStore.messages,
       },
     };
   } else if (action.type === setMessageStoreMessages) {
     let threads = { ...messageStore.threads };
     let local = { ...messageStore.local };
 
     // Store message IDs already contained within threads so that we
     // do not insert duplicates
     const existingMessageIDs = new Set();
     for (const threadID in threads) {
       threads[threadID].messageIDs.forEach(msgID => {
         existingMessageIDs.add(msgID);
       });
     }
     const threadsNeedMsgIDsResorting = new Set();
     const actionPayloadMessages = translateClientDBMessageInfosToRawMessageInfos(
       action.payload,
     );
 
     // When starting the app on native, we filter out any local-only multimedia
     // messages because the relevant context is no longer available
     const messageIDsToBeRemoved = [];
     for (const id in actionPayloadMessages) {
       const message = actionPayloadMessages[id];
       const { threadID } = message;
       if (
         (message.type === messageTypes.IMAGES ||
           message.type === messageTypes.MULTIMEDIA) &&
         !message.id
       ) {
         messageIDsToBeRemoved.push(id);
         threads = {
           ...threads,
           [threadID]: {
             ...threads[threadID],
             messageIDs: threads[threadID].messageIDs.filter(
               curMessageID => curMessageID !== id,
             ),
           },
         };
         local = _pickBy(
           (localInfo: LocalMessageInfo, key: string) => key !== id,
         )(local);
       } else if (!existingMessageIDs.has(id)) {
         threads = {
           ...threads,
           [threadID]: {
             ...threads[threadID],
             messageIDs: [...threads[threadID].messageIDs, id],
           },
         };
         threadsNeedMsgIDsResorting.add(threadID);
       }
     }
 
     for (const threadID of threadsNeedMsgIDsResorting) {
       threads[threadID].messageIDs = sortMessageIDs(actionPayloadMessages)(
         threads[threadID].messageIDs,
       );
     }
 
     messageStore = {
       ...messageStore,
       messages: actionPayloadMessages,
       threads: threads,
       local: local,
     };
 
     if (messageIDsToBeRemoved.length === 0) {
       return { messageStoreOperations: [], messageStore };
     }
 
     const messageStoreOperations: MessageStoreOperation[] = [
       {
         type: 'remove',
         payload: { ids: messageIDsToBeRemoved },
       },
     ];
 
     const processedMessageStore = processMessageStoreOperations(
       messageStore,
       messageStoreOperations,
     );
 
     return {
       messageStoreOperations,
       messageStore: {
         ...messageStore,
         messages: processedMessageStore.messages,
       },
     };
   }
   return { messageStoreOperations: [], messageStore };
 }
 
 type MergedUpdatesWithMessages = {
   +rawMessageInfos: $ReadOnlyArray<RawMessageInfo>,
   +truncationStatuses: MessageTruncationStatuses,
 };
 function mergeUpdatesWithMessageInfos(
   messageInfos: $ReadOnlyArray<RawMessageInfo>,
   newUpdates: $ReadOnlyArray<ClientUpdateInfo>,
   truncationStatuses?: MessageTruncationStatuses,
 ): MergedUpdatesWithMessages {
   const messageIDs = new Set(messageInfos.map(messageInfo => messageInfo.id));
   const mergedMessageInfos = [...messageInfos];
   const mergedTruncationStatuses = { ...truncationStatuses };
 
   for (const updateInfo of newUpdates) {
     if (updateInfo.type !== updateTypes.JOIN_THREAD) {
       continue;
     }
     for (const messageInfo of updateInfo.rawMessageInfos) {
       if (messageIDs.has(messageInfo.id)) {
         continue;
       }
       mergedMessageInfos.push(messageInfo);
       messageIDs.add(messageInfo.id);
     }
 
     mergedTruncationStatuses[
       updateInfo.threadInfo.id
     ] = combineTruncationStatuses(
       updateInfo.truncationStatus,
       mergedTruncationStatuses[updateInfo.threadInfo.id],
     );
   }
   return {
     rawMessageInfos: mergedMessageInfos,
     truncationStatuses: mergedTruncationStatuses,
   };
 }
 
 export { freshMessageStore, reduceMessageStore };
diff --git a/lib/selectors/thread-selectors.js b/lib/selectors/thread-selectors.js
index 267f387fd..c82342bfe 100644
--- a/lib/selectors/thread-selectors.js
+++ b/lib/selectors/thread-selectors.js
@@ -1,414 +1,414 @@
 // @flow
 
 import _compact from 'lodash/fp/compact';
 import _filter from 'lodash/fp/filter';
 import _flow from 'lodash/fp/flow';
 import _map from 'lodash/fp/map';
 import _mapValues from 'lodash/fp/mapValues';
 import _orderBy from 'lodash/fp/orderBy';
 import _some from 'lodash/fp/some';
 import _sortBy from 'lodash/fp/sortBy';
 import _memoize from 'lodash/memoize';
 import { createSelector } from 'reselect';
 import { createObjectSelector } from 'reselect-map';
 
 import { createEntryInfo } from '../shared/entry-utils';
 import { getMostRecentNonLocalMessageID } from '../shared/message-utils';
 import {
   threadInHomeChatList,
   threadInBackgroundChatList,
   threadInFilterList,
   threadInfoFromRawThreadInfo,
   threadHasPermission,
   threadInChatList,
   threadHasAdminRole,
   roleIsAdminRole,
   threadIsPending,
-  getLocallyUniqueThreadID,
+  getPendingThreadID,
 } from '../shared/thread-utils';
 import type { EntryInfo } from '../types/entry-types';
 import type { MessageStore, RawMessageInfo } from '../types/message-types';
 import type { BaseAppState } from '../types/redux-types';
 import {
   type ThreadInfo,
   type RawThreadInfo,
   type RelativeMemberInfo,
   threadPermissions,
   threadTypes,
   type SidebarInfo,
 } from '../types/thread-types';
 import { dateString, dateFromString } from '../utils/date-utils';
 import { values } from '../utils/objects';
 import {
   filteredThreadIDsSelector,
   includeDeletedSelector,
 } from './calendar-filter-selectors';
 import { relativeMemberInfoSelectorForMembersOfThread } from './user-selectors';
 
 const _mapValuesWithKeys = _mapValues.convert({ cap: false });
 
 type ThreadInfoSelectorType = (
   state: BaseAppState<*>,
 ) => { +[id: string]: ThreadInfo };
 const threadInfoSelector: ThreadInfoSelectorType = createObjectSelector(
   (state: BaseAppState<*>) => state.threadStore.threadInfos,
   (state: BaseAppState<*>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<*>) => state.userStore.userInfos,
   threadInfoFromRawThreadInfo,
 );
 
 const canBeOnScreenThreadInfos: (
   state: BaseAppState<*>,
 ) => $ReadOnlyArray<ThreadInfo> = createSelector(
   threadInfoSelector,
   (threadInfos: { +[id: string]: ThreadInfo }) => {
     const result = [];
     for (const threadID in threadInfos) {
       const threadInfo = threadInfos[threadID];
       if (!threadInFilterList(threadInfo)) {
         continue;
       }
       result.push(threadInfo);
     }
     return result;
   },
 );
 
 const onScreenThreadInfos: (
   state: BaseAppState<*>,
 ) => $ReadOnlyArray<ThreadInfo> = createSelector(
   filteredThreadIDsSelector,
   canBeOnScreenThreadInfos,
   (
     inputThreadIDs: ?$ReadOnlySet<string>,
     threadInfos: $ReadOnlyArray<ThreadInfo>,
   ) => {
     const threadIDs = inputThreadIDs;
     if (!threadIDs) {
       return threadInfos;
     }
     return threadInfos.filter(threadInfo => threadIDs.has(threadInfo.id));
   },
 );
 
 const onScreenEntryEditableThreadInfos: (
   state: BaseAppState<*>,
 ) => $ReadOnlyArray<ThreadInfo> = createSelector(
   onScreenThreadInfos,
   (threadInfos: $ReadOnlyArray<ThreadInfo>) =>
     threadInfos.filter(threadInfo =>
       threadHasPermission(threadInfo, threadPermissions.EDIT_ENTRIES),
     ),
 );
 
 const entryInfoSelector: (
   state: BaseAppState<*>,
 ) => { +[id: string]: EntryInfo } = createObjectSelector(
   (state: BaseAppState<*>) => state.entryStore.entryInfos,
   (state: BaseAppState<*>) => state.currentUserInfo && state.currentUserInfo.id,
   (state: BaseAppState<*>) => state.userStore.userInfos,
   createEntryInfo,
 );
 
 // "current" means within startDate/endDate range, not deleted, and in
 // onScreenThreadInfos
 const currentDaysToEntries: (
   state: BaseAppState<*>,
 ) => { +[dayString: string]: EntryInfo[] } = createSelector(
   entryInfoSelector,
   (state: BaseAppState<*>) => state.entryStore.daysToEntries,
   (state: BaseAppState<*>) => state.navInfo.startDate,
   (state: BaseAppState<*>) => state.navInfo.endDate,
   onScreenThreadInfos,
   includeDeletedSelector,
   (
     entryInfos: { +[id: string]: EntryInfo },
     daysToEntries: { +[day: string]: string[] },
     startDateString: string,
     endDateString: string,
     onScreen: $ReadOnlyArray<ThreadInfo>,
     includeDeleted: boolean,
   ) => {
     const allDaysWithinRange = {},
       startDate = dateFromString(startDateString),
       endDate = dateFromString(endDateString);
     for (
       const curDate = startDate;
       curDate <= endDate;
       curDate.setDate(curDate.getDate() + 1)
     ) {
       allDaysWithinRange[dateString(curDate)] = [];
     }
     return _mapValuesWithKeys((_: string[], dayString: string) =>
       _flow(
         _map((entryID: string) => entryInfos[entryID]),
         _compact,
         _filter(
           (entryInfo: EntryInfo) =>
             (includeDeleted || !entryInfo.deleted) &&
             _some(['id', entryInfo.threadID])(onScreen),
         ),
         _sortBy('creationTime'),
       )(daysToEntries[dayString] ? daysToEntries[dayString] : []),
     )(allDaysWithinRange);
   },
 );
 
 const childThreadInfos: (
   state: BaseAppState<*>,
 ) => { +[id: string]: $ReadOnlyArray<ThreadInfo> } = createSelector(
   threadInfoSelector,
   (threadInfos: { +[id: string]: ThreadInfo }) => {
     const result = {};
     for (const id in threadInfos) {
       const threadInfo = threadInfos[id];
       const parentThreadID = threadInfo.parentThreadID;
       if (parentThreadID === null || parentThreadID === undefined) {
         continue;
       }
       if (result[parentThreadID] === undefined) {
         result[parentThreadID] = [];
       }
       result[parentThreadID].push(threadInfo);
     }
     return result;
   },
 );
 
 function getMostRecentRawMessageInfo(
   threadInfo: ThreadInfo,
   messageStore: MessageStore,
 ): ?RawMessageInfo {
   const thread = messageStore.threads[threadInfo.id];
   if (!thread) {
     return null;
   }
   for (const messageID of thread.messageIDs) {
     return messageStore.messages[messageID];
   }
   return null;
 }
 
 const sidebarInfoSelector: (
   state: BaseAppState<*>,
 ) => { +[id: string]: $ReadOnlyArray<SidebarInfo> } = createObjectSelector(
   childThreadInfos,
   (state: BaseAppState<*>) => state.messageStore,
   (childThreads: $ReadOnlyArray<ThreadInfo>, messageStore: MessageStore) => {
     const sidebarInfos = [];
     for (const childThreadInfo of childThreads) {
       if (
         !threadInChatList(childThreadInfo) ||
         childThreadInfo.type !== threadTypes.SIDEBAR
       ) {
         continue;
       }
       const mostRecentRawMessageInfo = getMostRecentRawMessageInfo(
         childThreadInfo,
         messageStore,
       );
       const lastUpdatedTime =
         mostRecentRawMessageInfo?.time ?? childThreadInfo.creationTime;
       const mostRecentNonLocalMessage = getMostRecentNonLocalMessageID(
         childThreadInfo.id,
         messageStore,
       );
       sidebarInfos.push({
         threadInfo: childThreadInfo,
         lastUpdatedTime,
         mostRecentNonLocalMessage,
       });
     }
     return _orderBy('lastUpdatedTime')('desc')(sidebarInfos);
   },
 );
 
 const unreadCount: (state: BaseAppState<*>) => number = createSelector(
   (state: BaseAppState<*>) => state.threadStore.threadInfos,
   (threadInfos: { +[id: string]: RawThreadInfo }): number =>
     values(threadInfos).filter(
       threadInfo =>
         threadInHomeChatList(threadInfo) && threadInfo.currentUser.unread,
     ).length,
 );
 
 const unreadBackgroundCount: (
   state: BaseAppState<*>,
 ) => number = createSelector(
   (state: BaseAppState<*>) => state.threadStore.threadInfos,
   (threadInfos: { +[id: string]: RawThreadInfo }): number =>
     values(threadInfos).filter(
       threadInfo =>
         threadInBackgroundChatList(threadInfo) && threadInfo.currentUser.unread,
     ).length,
 );
 
 const baseAncestorThreadInfos = (threadID: string) =>
   createSelector(
     (state: BaseAppState<*>) => threadInfoSelector(state),
     (threadInfos: {
       +[id: string]: ThreadInfo,
     }): $ReadOnlyArray<ThreadInfo> => {
       const pathComponents: ThreadInfo[] = [];
       let node: ?ThreadInfo = threadInfos[threadID];
       while (node) {
         pathComponents.push(node);
         node = node.parentThreadID ? threadInfos[node.parentThreadID] : null;
       }
       pathComponents.reverse();
       return pathComponents;
     },
   );
 
 const ancestorThreadInfos: (
   threadID: string,
 ) => (state: BaseAppState<*>) => $ReadOnlyArray<ThreadInfo> = _memoize(
   baseAncestorThreadInfos,
 );
 
 const baseOtherUsersButNoOtherAdmins = (threadID: string) =>
   createSelector(
     (state: BaseAppState<*>) => state.threadStore.threadInfos[threadID],
     relativeMemberInfoSelectorForMembersOfThread(threadID),
     (
       threadInfo: ?RawThreadInfo,
       members: $ReadOnlyArray<RelativeMemberInfo>,
     ): boolean => {
       if (!threadInfo) {
         return false;
       }
       if (!threadHasAdminRole(threadInfo)) {
         return false;
       }
       let otherUsersExist = false;
       let otherAdminsExist = false;
       for (const member of members) {
         const role = member.role;
         if (role === undefined || role === null || member.isViewer) {
           continue;
         }
         otherUsersExist = true;
         if (roleIsAdminRole(threadInfo?.roles[role])) {
           otherAdminsExist = true;
           break;
         }
       }
       return otherUsersExist && !otherAdminsExist;
     },
   );
 
 const otherUsersButNoOtherAdmins: (
   threadID: string,
 ) => (state: BaseAppState<*>) => boolean = _memoize(
   baseOtherUsersButNoOtherAdmins,
 );
 
 function mostRecentlyReadThread(
   messageStore: MessageStore,
   threadInfos: { +[id: string]: RawThreadInfo },
 ): ?string {
   let mostRecent = null;
   for (const threadID in threadInfos) {
     const threadInfo = threadInfos[threadID];
     if (threadInfo.currentUser.unread) {
       continue;
     }
     const threadMessageInfo = messageStore.threads[threadID];
     if (!threadMessageInfo) {
       continue;
     }
     const mostRecentMessageTime =
       threadMessageInfo.messageIDs.length === 0
         ? threadInfo.creationTime
         : messageStore.messages[threadMessageInfo.messageIDs[0]].time;
     if (mostRecent && mostRecent.time >= mostRecentMessageTime) {
       continue;
     }
 
     const topLevelThreadID =
       threadInfo.type === threadTypes.SIDEBAR
         ? threadInfo.parentThreadID
         : threadID;
     mostRecent = { threadID: topLevelThreadID, time: mostRecentMessageTime };
   }
   return mostRecent ? mostRecent.threadID : null;
 }
 
 const mostRecentlyReadThreadSelector: (
   state: BaseAppState<*>,
 ) => ?string = createSelector(
   (state: BaseAppState<*>) => state.messageStore,
   (state: BaseAppState<*>) => state.threadStore.threadInfos,
   mostRecentlyReadThread,
 );
 
 const threadInfoFromSourceMessageIDSelector: (
   state: BaseAppState<*>,
 ) => { +[id: string]: ThreadInfo } = createSelector(
   (state: BaseAppState<*>) => state.threadStore.threadInfos,
   threadInfoSelector,
   (
     rawThreadInfos: { +[id: string]: RawThreadInfo },
     threadInfos: { +[id: string]: ThreadInfo },
   ) => {
-    const locallyUniqueToRealizedThreadIDs = locallyUniqueToRealizedThreadIDsSelector(
+    const pendingToRealizedThreadIDs = pendingToRealizedThreadIDsSelector(
       rawThreadInfos,
     );
     const result = {};
-    for (const realizedID of locallyUniqueToRealizedThreadIDs.values()) {
+    for (const realizedID of pendingToRealizedThreadIDs.values()) {
       const threadInfo = threadInfos[realizedID];
       if (threadInfo && threadInfo.sourceMessageID) {
         result[threadInfo.sourceMessageID] = threadInfo;
       }
     }
     return result;
   },
 );
-const locallyUniqueToRealizedThreadIDsSelector: (rawThreadInfos: {
+const pendingToRealizedThreadIDsSelector: (rawThreadInfos: {
   +[id: string]: RawThreadInfo,
 }) => $ReadOnlyMap<string, string> = createSelector(
   (rawThreadInfos: { +[id: string]: RawThreadInfo }) => rawThreadInfos,
   (rawThreadInfos: { +[id: string]: RawThreadInfo }) => {
     const result = new Map();
     for (const threadID in rawThreadInfos) {
       const rawThreadInfo = rawThreadInfos[threadID];
       if (threadIsPending(threadID)) {
         continue;
       }
       const actualMemberIDs = rawThreadInfo.members
         .filter(member => member.role)
         .map(member => member.id);
-      const locallyUniqueThreadID = getLocallyUniqueThreadID(
+      const pendingThreadID = getPendingThreadID(
         rawThreadInfo.type,
         actualMemberIDs,
         rawThreadInfo.sourceMessageID,
       );
-      const existingResult = result.get(locallyUniqueThreadID);
+      const existingResult = result.get(pendingThreadID);
       if (
         !existingResult ||
         rawThreadInfos[existingResult].creationTime > rawThreadInfo.creationTime
       ) {
-        result.set(locallyUniqueThreadID, threadID);
+        result.set(pendingThreadID, threadID);
       }
     }
     return result;
   },
 );
 
 export {
   ancestorThreadInfos,
   threadInfoSelector,
   onScreenThreadInfos,
   onScreenEntryEditableThreadInfos,
   entryInfoSelector,
   currentDaysToEntries,
   childThreadInfos,
   unreadCount,
   unreadBackgroundCount,
   otherUsersButNoOtherAdmins,
   mostRecentlyReadThread,
   mostRecentlyReadThreadSelector,
   sidebarInfoSelector,
   threadInfoFromSourceMessageIDSelector,
-  locallyUniqueToRealizedThreadIDsSelector,
+  pendingToRealizedThreadIDsSelector,
 };
diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
index 01810d568..0f1daba55 100644
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -1,1465 +1,1459 @@
 // @flow
 
 import invariant from 'invariant';
 import _find from 'lodash/fp/find';
 import * as React from 'react';
 import stringHash from 'string-hash';
 import tinycolor from 'tinycolor2';
 
 import {
   fetchMostRecentMessagesActionTypes,
   fetchMostRecentMessages,
 } from '../actions/message-actions';
 import {
   changeThreadMemberRolesActionTypes,
   newThreadActionTypes,
   removeUsersFromThreadActionTypes,
 } from '../actions/thread-actions';
 import { searchUsers as searchUserCall } from '../actions/user-actions';
 import ashoat from '../facts/ashoat';
 import genesis from '../facts/genesis';
 import {
   permissionLookup,
   getAllThreadPermissions,
   makePermissionsBlob,
 } from '../permissions/thread-permissions';
 import type {
   ChatThreadItem,
   ChatMessageInfoItem,
 } from '../selectors/chat-selectors';
 import { threadSearchIndex as threadSearchIndexSelector } from '../selectors/nav-selectors';
 import {
   threadInfoSelector,
-  locallyUniqueToRealizedThreadIDsSelector,
+  pendingToRealizedThreadIDsSelector,
 } from '../selectors/thread-selectors';
 import {
   getRelativeMemberInfos,
   usersWithPersonalThreadSelector,
 } from '../selectors/user-selectors';
 import type { CalendarQuery } from '../types/entry-types';
 import type {
   RobotextMessageInfo,
   ComposableMessageInfo,
 } from '../types/message-types';
 import { userRelationshipStatus } from '../types/relationship-types';
 import {
   type RawThreadInfo,
   type ThreadInfo,
   type ThreadPermission,
   type MemberInfo,
   type ServerThreadInfo,
   type RelativeMemberInfo,
   type ThreadCurrentUserInfo,
   type RoleInfo,
   type ServerMemberInfo,
   type ThreadPermissionsInfo,
   type ThreadType,
   type ClientNewThreadRequest,
   type NewThreadResult,
   type ChangeThreadSettingsPayload,
   threadTypes,
   threadPermissions,
   threadTypeIsCommunityRoot,
   assertThreadType,
 } from '../types/thread-types';
 import { type ClientUpdateInfo, updateTypes } from '../types/update-types';
 import type {
   GlobalAccountUserInfo,
   UserInfos,
   UserInfo,
   AccountUserInfo,
 } from '../types/user-types';
 import { useDispatchActionPromise, useServerCall } from '../utils/action-utils';
 import type { DispatchActionPromise } from '../utils/action-utils';
 import { values } from '../utils/objects';
 import { useSelector } from '../utils/redux-utils';
 import { firstLine } from '../utils/string-utils';
 import { pluralize, trimText } from '../utils/text-utils';
 import { type ParserRules } from './markdown';
 import { getMessageTitle } from './message-utils';
 import { relationshipBlockedInEitherDirection } from './relationship-utils';
 import threadWatcher from './thread-watcher';
 
 function colorIsDark(color: string): boolean {
   return tinycolor(`#${color}`).isDark();
 }
 
 const selectedThreadColorsObj = Object.freeze({
   a: '4b87aa',
   b: '5c9f5f',
   c: 'b8753d',
   d: 'aa4b4b',
   e: '6d49ab',
   f: 'c85000',
   g: '008f83',
   h: '648caa',
   i: '57697f',
   j: '575757',
 });
 
 const selectedThreadColors: $ReadOnlyArray<string> = values(
   selectedThreadColorsObj,
 );
 export type SelectedThreadColors = $Values<typeof selectedThreadColorsObj>;
 
 function generateRandomColor(): string {
   return selectedThreadColors[
     Math.floor(Math.random() * selectedThreadColors.length)
   ];
 }
 
 function generatePendingThreadColor(userIDs: $ReadOnlyArray<string>): string {
   const ids = [...userIDs].sort().join('#');
   const colorIdx = stringHash(ids) % selectedThreadColors.length;
   return selectedThreadColors[colorIdx];
 }
 
 function threadHasPermission(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
   permission: ThreadPermission,
 ): boolean {
   if (!threadInfo) {
     return false;
   }
   invariant(
     !permissionsDisabledByBlock.has(permission) || threadInfo?.uiName,
     `${permission} can be disabled by a block, but threadHasPermission can't ` +
       'check for a block on RawThreadInfo. Please pass in ThreadInfo instead!',
   );
   if (!threadInfo.currentUser.permissions[permission]) {
     return false;
   }
   return threadInfo.currentUser.permissions[permission].value;
 }
 
 function viewerIsMember(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(
     threadInfo &&
     threadInfo.currentUser.role !== null &&
     threadInfo.currentUser.role !== undefined
   );
 }
 
 function threadIsInHome(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(threadInfo && threadInfo.currentUser.subscription.home);
 }
 
 // Can have messages
 function threadInChatList(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return (
     viewerIsMember(threadInfo) &&
     threadHasPermission(threadInfo, threadPermissions.VISIBLE)
   );
 }
 
 function threadIsTopLevel(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return threadInChatList(threadInfo) && threadIsChannel(threadInfo);
 }
 
 function threadIsChannel(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return !!(threadInfo && threadInfo.type !== threadTypes.SIDEBAR);
 }
 
 function threadIsSidebar(threadInfo: ?(ThreadInfo | RawThreadInfo)): boolean {
   return threadInfo?.type === threadTypes.SIDEBAR;
 }
 
 function threadInBackgroundChatList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && !threadIsInHome(threadInfo);
 }
 
 function threadInHomeChatList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return threadInChatList(threadInfo) && threadIsInHome(threadInfo);
 }
 
 // Can have Calendar entries,
 // does appear as a top-level entity in the thread list
 function threadInFilterList(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
 ): boolean {
   return (
     threadInChatList(threadInfo) &&
     !!threadInfo &&
     threadInfo.type !== threadTypes.SIDEBAR
   );
 }
 
 function userIsMember(
   threadInfo: ?(ThreadInfo | RawThreadInfo),
   userID: string,
 ): boolean {
   if (!threadInfo) {
     return false;
   }
   if (threadInfo.id === genesis.id) {
     return true;
   }
   return threadInfo.members.some(member => member.id === userID && member.role);
 }
 
 function threadActualMembers(
   memberInfos: $ReadOnlyArray<MemberInfo | RelativeMemberInfo>,
 ): $ReadOnlyArray<string> {
   return memberInfos
     .filter(memberInfo => memberInfo.role)
     .map(memberInfo => memberInfo.id);
 }
 
 function threadIsGroupChat(threadInfo: ThreadInfo | RawThreadInfo): boolean {
   return (
     threadInfo.members.filter(member => {
       if (
         member.id === ashoat.id &&
         !member.role &&
         threadInfo.community === genesis.id
       ) {
         return false;
       }
       return member.role || member.permissions[threadPermissions.VOICED]?.value;
     }).length > 2
   );
 }
 
 function threadOrParentThreadIsGroupChat(
   threadInfo: RawThreadInfo | ThreadInfo,
 ) {
   return threadInfo.members.length > 2;
 }
 
 function threadIsPending(threadID: ?string): boolean {
   return !!threadID?.startsWith('pending');
 }
 
 function getThreadOtherUsers(
   threadInfo: ThreadInfo | RawThreadInfo,
   viewerID: ?string,
 ): string[] {
   const otherUserIDs = [];
   for (const member of threadInfo.members) {
     if (!member.role || member.id === viewerID) {
       continue;
     }
     otherUserIDs.push(member.id);
   }
   return otherUserIDs;
 }
 
 function getSingleOtherUser(
   threadInfo: ThreadInfo | RawThreadInfo,
   viewerID: ?string,
 ): ?string {
   if (!viewerID) {
     return undefined;
   }
   const otherMemberIDs = getThreadOtherUsers(threadInfo, viewerID);
   if (otherMemberIDs.length !== 1) {
     return undefined;
   }
   return otherMemberIDs[0];
 }
 
-function getLocallyUniqueThreadID(
+function getPendingThreadID(
   threadType: ThreadType,
   memberIDs: $ReadOnlyArray<string>,
   sourceMessageID: ?string,
 ): string {
   const pendingThreadKey = sourceMessageID
     ? `sidebar/${sourceMessageID}`
     : [...memberIDs].sort().join('+');
   const pendingThreadTypeString = sourceMessageID ? '' : `type${threadType}/`;
   return `pending/${pendingThreadTypeString}${pendingThreadKey}`;
 }
 
-const locallyUniqueThreadIDRegex =
+const pendingThreadIDRegex =
   'pending/(type[0-9]+/[0-9]+(\\+[0-9]+)*|sidebar/[0-9]+)';
 
-type LocallyUniqueThreadIDContents = {
+type PendingThreadIDContents = {
   +threadType: ThreadType,
   +memberIDs: $ReadOnlyArray<string>,
   +sourceMessageID: ?string,
 };
 
-function parseLocallyUniqueThreadID(
+function parsePendingThreadID(
   pendingThreadID: string,
-): ?LocallyUniqueThreadIDContents {
-  const locallyUniqueRegex = new RegExp(`^${locallyUniqueThreadIDRegex}$`);
-  const pendingThreadIDMatches = locallyUniqueRegex.exec(pendingThreadID);
+): ?PendingThreadIDContents {
+  const pendingRegex = new RegExp(`^${pendingThreadIDRegex}$`);
+  const pendingThreadIDMatches = pendingRegex.exec(pendingThreadID);
   if (!pendingThreadIDMatches) {
     return null;
   }
   const [threadTypeString, threadKey] = pendingThreadIDMatches[1].split('/');
   const threadType =
     threadTypeString === 'sidebar'
       ? threadTypes.SIDEBAR
       : assertThreadType(Number(threadTypeString.replace('type', '')));
   const memberIDs = threadTypeString === 'sidebar' ? [] : threadKey.split('+');
   const sourceMessageID = threadTypeString === 'sidebar' ? threadKey : null;
   return {
     threadType,
     memberIDs,
     sourceMessageID,
   };
 }
 
 type CreatePendingThreadArgs = {
   +viewerID: string,
   +threadType: ThreadType,
   +members?: $ReadOnlyArray<GlobalAccountUserInfo | UserInfo>,
   +parentThreadInfo?: ?ThreadInfo,
   +threadColor?: ?string,
   +name?: ?string,
   +sourceMessageID?: string,
 };
 
 function createPendingThread({
   viewerID,
   threadType,
   members,
   parentThreadInfo,
   threadColor,
   name,
   sourceMessageID,
 }: CreatePendingThreadArgs): ThreadInfo {
   const now = Date.now();
   const nonViewerMembers = members
     ? members.filter(member => member.id !== viewerID)
     : [];
   const nonViewerMemberIDs = nonViewerMembers.map(member => member.id);
   const memberIDs = [...nonViewerMemberIDs, viewerID];
-  const threadID = getLocallyUniqueThreadID(
-    threadType,
-    memberIDs,
-    sourceMessageID,
-  );
+  const threadID = getPendingThreadID(threadType, memberIDs, sourceMessageID);
 
   const permissions = {
     [threadPermissions.KNOW_OF]: true,
     [threadPermissions.VISIBLE]: true,
     [threadPermissions.VOICED]: true,
   };
 
   const membershipPermissions = getAllThreadPermissions(
     makePermissionsBlob(permissions, null, threadID, threadType),
     threadID,
   );
   const role = {
     id: `${threadID}/role`,
     name: 'Members',
     permissions,
     isDefault: true,
   };
 
   const rawThreadInfo = {
     id: threadID,
     type: threadType,
     name: name ?? null,
     description: null,
     color: threadColor ?? generatePendingThreadColor(memberIDs),
     creationTime: now,
     parentThreadID: parentThreadInfo?.id ?? null,
     containingThreadID: getContainingThreadID(parentThreadInfo, threadType),
     community: getCommunity(parentThreadInfo),
     members: [
       {
         id: viewerID,
         role: role.id,
         permissions: membershipPermissions,
         isSender: false,
       },
       ...nonViewerMembers.map(member => ({
         id: member.id,
         role: role.id,
         permissions: membershipPermissions,
         isSender: false,
       })),
     ],
     roles: {
       [role.id]: role,
     },
     currentUser: {
       role: role.id,
       permissions: membershipPermissions,
       subscription: {
         pushNotifs: false,
         home: false,
       },
       unread: false,
     },
     repliesCount: 0,
     sourceMessageID,
   };
 
   const userInfos = {};
   nonViewerMembers.forEach(member => (userInfos[member.id] = member));
 
   return threadInfoFromRawThreadInfo(rawThreadInfo, viewerID, userInfos);
 }
 
 function createPendingThreadItem(
   viewerID: string,
   user: GlobalAccountUserInfo,
 ): ChatThreadItem {
   const threadInfo = createPendingThread({
     viewerID,
     threadType: threadTypes.PERSONAL,
     members: [user],
   });
 
   return {
     type: 'chatThreadItem',
     threadInfo,
     mostRecentMessageInfo: null,
     mostRecentNonLocalMessage: null,
     lastUpdatedTime: threadInfo.creationTime,
     lastUpdatedTimeIncludingSidebars: threadInfo.creationTime,
     sidebars: [],
     pendingPersonalThreadUserInfo: {
       id: user.id,
       username: user.username,
     },
   };
 }
 
 function createPendingSidebar(
   sourceMessageInfo: ComposableMessageInfo | RobotextMessageInfo,
   parentThreadInfo: ThreadInfo,
   viewerID: string,
   markdownRules: ParserRules,
 ): ThreadInfo {
   const { color, type: parentThreadType } = parentThreadInfo;
 
   const messageTitle = getMessageTitle(
     sourceMessageInfo,
     parentThreadInfo,
     markdownRules,
     'global_viewer',
   );
   const threadName = trimText(messageTitle, 30);
 
   const initialMembers = new Map();
   if (userIsMember(parentThreadInfo, sourceMessageInfo.creator.id)) {
     const {
       id: sourceAuthorID,
       username: sourceAuthorUsername,
     } = sourceMessageInfo.creator;
     invariant(
       sourceAuthorUsername,
       'sourceAuthorUsername should be set in createPendingSidebar',
     );
     const initialMemberUserInfo: GlobalAccountUserInfo = {
       id: sourceAuthorID,
       username: sourceAuthorUsername,
     };
     initialMembers.set(sourceAuthorID, initialMemberUserInfo);
   }
   const singleOtherUser = getSingleOtherUser(parentThreadInfo, viewerID);
   if (parentThreadType === threadTypes.PERSONAL && singleOtherUser) {
     const singleOtherUsername = parentThreadInfo.members.find(
       member => member.id === singleOtherUser,
     )?.username;
     invariant(
       singleOtherUsername,
       'singleOtherUsername should be set in createPendingSidebar',
     );
     const singleOtherUserInfo: GlobalAccountUserInfo = {
       id: singleOtherUser,
       username: singleOtherUsername,
     };
     initialMembers.set(singleOtherUser, singleOtherUserInfo);
   }
 
   return createPendingThread({
     viewerID,
     threadType: threadTypes.SIDEBAR,
     members: [...initialMembers.values()],
     parentThreadInfo,
     threadColor: color,
     name: threadName,
     sourceMessageID: sourceMessageInfo.id,
   });
 }
 
 function pendingThreadType(numberOfOtherMembers: number): 4 | 6 | 7 {
   if (numberOfOtherMembers === 0) {
     return threadTypes.PRIVATE;
   } else if (numberOfOtherMembers === 1) {
     return threadTypes.PERSONAL;
   } else {
     return threadTypes.LOCAL;
   }
 }
 
 function threadTypeCanBePending(threadType: ThreadType): boolean {
   return (
     threadType === threadTypes.PERSONAL ||
     threadType === threadTypes.LOCAL ||
     threadType === threadTypes.SIDEBAR ||
     threadType === threadTypes.PRIVATE
   );
 }
 
 type CreateRealThreadParameters = {
   +threadInfo: ThreadInfo,
   +dispatchActionPromise: DispatchActionPromise,
   +createNewThread: ClientNewThreadRequest => Promise<NewThreadResult>,
   +sourceMessageID: ?string,
   +viewerID: ?string,
   +handleError?: () => mixed,
   +calendarQuery: CalendarQuery,
 };
 async function createRealThreadFromPendingThread({
   threadInfo,
   dispatchActionPromise,
   createNewThread,
   sourceMessageID,
   viewerID,
   calendarQuery,
 }: CreateRealThreadParameters): Promise<string> {
   if (!threadIsPending(threadInfo.id)) {
     return threadInfo.id;
   }
 
   const otherMemberIDs = getThreadOtherUsers(threadInfo, viewerID);
   let resultPromise;
   if (threadInfo.type !== threadTypes.SIDEBAR) {
     invariant(
       otherMemberIDs.length > 0,
       'otherMemberIDs should not be empty for threads',
     );
     resultPromise = createNewThread({
       type: pendingThreadType(otherMemberIDs.length),
       initialMemberIDs: otherMemberIDs,
       color: threadInfo.color,
       calendarQuery,
     });
   } else {
     invariant(
       sourceMessageID,
       'sourceMessageID should be set when creating a sidebar',
     );
     resultPromise = createNewThread({
       type: threadTypes.SIDEBAR,
       initialMemberIDs: otherMemberIDs,
       color: threadInfo.color,
       sourceMessageID,
       parentThreadID: threadInfo.parentThreadID,
       name: threadInfo.name,
       calendarQuery,
     });
   }
   dispatchActionPromise(newThreadActionTypes, resultPromise);
   const { newThreadID } = await resultPromise;
   return newThreadID;
 }
 
 type RawThreadInfoOptions = {
   +includeVisibilityRules?: ?boolean,
   +filterMemberList?: ?boolean,
   +hideThreadStructure?: ?boolean,
   +shimThreadTypes?: ?{
     +[inType: ThreadType]: ThreadType,
   },
   +filterDetailedThreadEditPermissions?: boolean,
 };
 function rawThreadInfoFromServerThreadInfo(
   serverThreadInfo: ServerThreadInfo,
   viewerID: string,
   options?: RawThreadInfoOptions,
 ): ?RawThreadInfo {
   const includeVisibilityRules = options?.includeVisibilityRules;
   const filterMemberList = options?.filterMemberList;
   const hideThreadStructure = options?.hideThreadStructure;
   const shimThreadTypes = options?.shimThreadTypes;
   const filterDetailedThreadEditPermissions =
     options?.filterDetailedThreadEditPermissions;
 
   const members = [];
   let currentUser;
   for (const serverMember of serverThreadInfo.members) {
     if (
       filterMemberList &&
       serverMember.id !== viewerID &&
       !serverMember.role &&
       !memberHasAdminPowers(serverMember)
     ) {
       continue;
     }
     if (
       serverThreadInfo.id === genesis.id &&
       serverMember.id !== viewerID &&
       serverMember.id !== ashoat.id
     ) {
       continue;
     }
     const memberPermissions = filterThreadEditDetailedPermissions(
       serverMember.permissions,
       filterDetailedThreadEditPermissions,
     );
     members.push({
       id: serverMember.id,
       role: serverMember.role,
       permissions: memberPermissions,
       isSender: serverMember.isSender,
     });
     if (serverMember.id === viewerID) {
       currentUser = {
         role: serverMember.role,
         permissions: memberPermissions,
         subscription: serverMember.subscription,
         unread: serverMember.unread,
       };
     }
   }
 
   let currentUserPermissions;
   if (currentUser) {
     currentUserPermissions = currentUser.permissions;
   } else {
     currentUserPermissions = filterThreadEditDetailedPermissions(
       getAllThreadPermissions(null, serverThreadInfo.id),
       filterDetailedThreadEditPermissions,
     );
     currentUser = {
       role: null,
       permissions: currentUserPermissions,
       subscription: {
         home: false,
         pushNotifs: false,
       },
       unread: null,
     };
   }
   if (!permissionLookup(currentUserPermissions, threadPermissions.KNOW_OF)) {
     return null;
   }
 
   let { type } = serverThreadInfo;
   if (
     shimThreadTypes &&
     shimThreadTypes[type] !== null &&
     shimThreadTypes[type] !== undefined
   ) {
     type = shimThreadTypes[type];
   }
 
   let rawThreadInfo: any = {
     id: serverThreadInfo.id,
     type,
     name: serverThreadInfo.name,
     description: serverThreadInfo.description,
     color: serverThreadInfo.color,
     creationTime: serverThreadInfo.creationTime,
     parentThreadID: serverThreadInfo.parentThreadID,
     members,
     roles: serverThreadInfo.roles,
     currentUser,
     repliesCount: serverThreadInfo.repliesCount,
   };
   if (!hideThreadStructure) {
     rawThreadInfo = {
       ...rawThreadInfo,
       containingThreadID: serverThreadInfo.containingThreadID,
       community: serverThreadInfo.community,
     };
   }
   const sourceMessageID = serverThreadInfo.sourceMessageID;
   if (sourceMessageID) {
     rawThreadInfo = { ...rawThreadInfo, sourceMessageID };
   }
   if (includeVisibilityRules) {
     return {
       ...rawThreadInfo,
       visibilityRules: rawThreadInfo.type,
     };
   }
   return rawThreadInfo;
 }
 
 function filterThreadEditDetailedPermissions(
   permissions: ThreadPermissionsInfo,
   shouldFilter: ?boolean,
 ): ThreadPermissionsInfo {
   if (!shouldFilter) {
     return permissions;
   }
   const {
     edit_thread_color,
     edit_thread_description,
     ...newPermissions
   } = permissions;
   return newPermissions;
 }
 
 function robotextName(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): string {
   const threadUsernames = getThreadOtherUsers(threadInfo, viewerID)
     .map(memberID => userInfos[memberID] && userInfos[memberID].username)
     .filter(Boolean);
   if (threadUsernames.length === 0) {
     return 'just you';
   }
   return pluralize(threadUsernames);
 }
 
 function threadUIName(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): string {
   return firstLine(
     threadInfo.name || robotextName(threadInfo, viewerID, userInfos),
   );
 }
 
 function threadInfoFromRawThreadInfo(
   rawThreadInfo: RawThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): ThreadInfo {
   let threadInfo: ThreadInfo = {
     id: rawThreadInfo.id,
     type: rawThreadInfo.type,
     name: rawThreadInfo.name,
     uiName: threadUIName(rawThreadInfo, viewerID, userInfos),
     description: rawThreadInfo.description,
     color: rawThreadInfo.color,
     creationTime: rawThreadInfo.creationTime,
     parentThreadID: rawThreadInfo.parentThreadID,
     containingThreadID: rawThreadInfo.containingThreadID,
     community: rawThreadInfo.community,
     members: getRelativeMemberInfos(rawThreadInfo, viewerID, userInfos),
     roles: rawThreadInfo.roles,
     currentUser: getCurrentUser(rawThreadInfo, viewerID, userInfos),
     repliesCount: rawThreadInfo.repliesCount,
   };
   const { sourceMessageID } = rawThreadInfo;
   if (sourceMessageID) {
     threadInfo = { ...threadInfo, sourceMessageID };
   }
   return threadInfo;
 }
 
 function getCurrentUser(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): ThreadCurrentUserInfo {
   if (!threadFrozenDueToBlock(threadInfo, viewerID, userInfos)) {
     return threadInfo.currentUser;
   }
 
   return {
     ...threadInfo.currentUser,
     permissions: {
       ...threadInfo.currentUser.permissions,
       ...disabledPermissions,
     },
   };
 }
 
 function threadIsWithBlockedUserOnly(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
   checkOnlyViewerBlock?: boolean,
 ): boolean {
   if (
     threadInfo.type !== threadTypes.PERSONAL &&
     (threadOrParentThreadIsGroupChat(threadInfo) ||
       threadOrParentThreadHasAdminRole(threadInfo))
   ) {
     return false;
   }
 
   const otherUserID = getSingleOtherUser(threadInfo, viewerID);
   if (!otherUserID) {
     return false;
   }
   const otherUserRelationshipStatus =
     userInfos[otherUserID]?.relationshipStatus;
 
   if (checkOnlyViewerBlock) {
     return (
       otherUserRelationshipStatus === userRelationshipStatus.BLOCKED_BY_VIEWER
     );
   }
 
   return (
     !!otherUserRelationshipStatus &&
     relationshipBlockedInEitherDirection(otherUserRelationshipStatus)
   );
 }
 
 function threadFrozenDueToBlock(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
   return threadIsWithBlockedUserOnly(threadInfo, viewerID, userInfos);
 }
 
 function threadFrozenDueToViewerBlock(
   threadInfo: RawThreadInfo | ThreadInfo,
   viewerID: ?string,
   userInfos: UserInfos,
 ): boolean {
   return threadIsWithBlockedUserOnly(threadInfo, viewerID, userInfos, true);
 }
 
 function rawThreadInfoFromThreadInfo(threadInfo: ThreadInfo): RawThreadInfo {
   let rawThreadInfo: RawThreadInfo = {
     id: threadInfo.id,
     type: threadInfo.type,
     name: threadInfo.name,
     description: threadInfo.description,
     color: threadInfo.color,
     creationTime: threadInfo.creationTime,
     parentThreadID: threadInfo.parentThreadID,
     containingThreadID: threadInfo.containingThreadID,
     community: threadInfo.community,
     members: threadInfo.members.map(relativeMemberInfo => ({
       id: relativeMemberInfo.id,
       role: relativeMemberInfo.role,
       permissions: relativeMemberInfo.permissions,
       isSender: relativeMemberInfo.isSender,
     })),
     roles: threadInfo.roles,
     currentUser: threadInfo.currentUser,
     repliesCount: threadInfo.repliesCount,
   };
   const { sourceMessageID } = threadInfo;
   if (sourceMessageID) {
     rawThreadInfo = { ...rawThreadInfo, sourceMessageID };
   }
   return rawThreadInfo;
 }
 
 const threadTypeDescriptions: { [ThreadType]: string } = {
   [threadTypes.COMMUNITY_OPEN_SUBTHREAD]:
     'Anybody in the parent channel can see an open subchannel.',
   [threadTypes.COMMUNITY_SECRET_SUBTHREAD]:
     'Only visible to its members and admins of ancestor channels.',
 };
 
 function usersInThreadInfo(threadInfo: RawThreadInfo | ThreadInfo): string[] {
   const userIDs = new Set();
   for (const member of threadInfo.members) {
     userIDs.add(member.id);
   }
   return [...userIDs];
 }
 
 function memberIsAdmin(
   memberInfo: RelativeMemberInfo | MemberInfo,
   threadInfo: ThreadInfo | RawThreadInfo,
 ): boolean {
   return !!(
     memberInfo.role && roleIsAdminRole(threadInfo.roles[memberInfo.role])
   );
 }
 
 // Since we don't have access to all of the ancestor ThreadInfos, we approximate
 // "parent admin" as anybody with CHANGE_ROLE permissions.
 function memberHasAdminPowers(
   memberInfo: RelativeMemberInfo | MemberInfo | ServerMemberInfo,
 ): boolean {
   return !!memberInfo.permissions[threadPermissions.CHANGE_ROLE]?.value;
 }
 
 function roleIsAdminRole(roleInfo: ?RoleInfo): boolean {
   return !!(roleInfo && !roleInfo.isDefault && roleInfo.name === 'Admins');
 }
 
 function threadHasAdminRole(
   threadInfo: ?(RawThreadInfo | ThreadInfo | ServerThreadInfo),
 ): boolean {
   if (!threadInfo) {
     return false;
   }
   return !!_find({ name: 'Admins' })(threadInfo.roles);
 }
 
 function threadOrParentThreadHasAdminRole(
   threadInfo: RawThreadInfo | ThreadInfo,
 ) {
   return (
     threadInfo.members.filter(member => memberHasAdminPowers(member)).length > 0
   );
 }
 
 function identifyInvalidatedThreads(
   updateInfos: $ReadOnlyArray<ClientUpdateInfo>,
 ): Set<string> {
   const invalidated = new Set();
   for (const updateInfo of updateInfos) {
     if (updateInfo.type === updateTypes.DELETE_THREAD) {
       invalidated.add(updateInfo.threadID);
     }
   }
   return invalidated;
 }
 
 const permissionsDisabledByBlockArray = [
   threadPermissions.VOICED,
   threadPermissions.EDIT_ENTRIES,
   threadPermissions.EDIT_THREAD_NAME,
   threadPermissions.EDIT_THREAD_COLOR,
   threadPermissions.EDIT_THREAD_DESCRIPTION,
   threadPermissions.CREATE_SUBCHANNELS,
   threadPermissions.CREATE_SIDEBARS,
   threadPermissions.JOIN_THREAD,
   threadPermissions.EDIT_PERMISSIONS,
   threadPermissions.ADD_MEMBERS,
   threadPermissions.REMOVE_MEMBERS,
 ];
 
 const permissionsDisabledByBlock: Set<ThreadPermission> = new Set(
   permissionsDisabledByBlockArray,
 );
 
 const disabledPermissions: ThreadPermissionsInfo = permissionsDisabledByBlockArray.reduce(
   (permissions: ThreadPermissionsInfo, permission: string) => ({
     ...permissions,
     [permission]: { value: false, source: null },
   }),
   {},
 );
 
 // Consider updating itemHeight in native/chat/chat-thread-list.react.js
 // if you change this
 const emptyItemText: string =
   `Background chats are just like normal chats, except they don't ` +
   `contribute to your unread count.\n\n` +
   `To move a chat over here, switch the “Background” option in its settings.`;
 
 const threadSearchText = (
   threadInfo: RawThreadInfo | ThreadInfo,
   userInfos: UserInfos,
   viewerID: ?string,
 ): string => {
   const searchTextArray = [];
   if (threadInfo.name) {
     searchTextArray.push(threadInfo.name);
   }
   if (threadInfo.description) {
     searchTextArray.push(threadInfo.description);
   }
   for (const member of threadInfo.members) {
     const isParentAdmin = memberHasAdminPowers(member);
     if (!member.role && !isParentAdmin) {
       continue;
     }
     if (member.id === viewerID) {
       continue;
     }
     const userInfo = userInfos[member.id];
     if (userInfo && userInfo.username) {
       searchTextArray.push(userInfo.username);
     }
   }
   return searchTextArray.join(' ');
 };
 
 function threadNoun(threadType: ThreadType): string {
   return threadType === threadTypes.SIDEBAR ? 'thread' : 'chat';
 }
 
 function threadLabel(threadType: ThreadType): string {
   if (
     threadType === threadTypes.COMMUNITY_OPEN_SUBTHREAD ||
     threadType === threadTypes.COMMUNITY_OPEN_ANNOUNCEMENT_SUBTHREAD
   ) {
     return 'Open';
   } else if (threadType === threadTypes.PERSONAL) {
     return 'Personal';
   } else if (threadType === threadTypes.SIDEBAR) {
     return 'Thread';
   } else if (threadType === threadTypes.PRIVATE) {
     return 'Private';
   } else if (
     threadType === threadTypes.COMMUNITY_ROOT ||
     threadType === threadTypes.COMMUNITY_ANNOUNCEMENT_ROOT ||
     threadType === threadTypes.GENESIS
   ) {
     return 'Community';
   } else {
     return 'Secret';
   }
 }
 
 function useWatchThread(threadInfo: ?ThreadInfo) {
   const dispatchActionPromise = useDispatchActionPromise();
   const callFetchMostRecentMessages = useServerCall(fetchMostRecentMessages);
 
   const threadID = threadInfo?.id;
   const threadNotInChatList = !threadInChatList(threadInfo);
   React.useEffect(() => {
     if (threadID && threadNotInChatList) {
       threadWatcher.watchID(threadID);
       dispatchActionPromise(
         fetchMostRecentMessagesActionTypes,
         callFetchMostRecentMessages(threadID),
       );
     }
     return () => {
       if (threadID && threadNotInChatList) {
         threadWatcher.removeID(threadID);
       }
     };
   }, [
     callFetchMostRecentMessages,
     dispatchActionPromise,
     threadNotInChatList,
     threadID,
   ]);
 }
 
 type ExistingThreadInfoFinderParams = {
   +searching: boolean,
   +userInfoInputArray: $ReadOnlyArray<AccountUserInfo>,
 };
 type ExistingThreadInfoFinder = (
   params: ExistingThreadInfoFinderParams,
 ) => ?ThreadInfo;
 function useExistingThreadInfoFinder(
   baseThreadInfo: ?ThreadInfo,
 ): ExistingThreadInfoFinder {
   const threadInfos = useSelector(threadInfoSelector);
   const viewerID = useSelector(
     state => state.currentUserInfo && state.currentUserInfo.id,
   );
   const userInfos = useSelector(state => state.userStore.userInfos);
 
-  const locallyUniqueToRealizedThreadIDs = useSelector(state =>
-    locallyUniqueToRealizedThreadIDsSelector(state.threadStore.threadInfos),
+  const pendingToRealizedThreadIDs = useSelector(state =>
+    pendingToRealizedThreadIDsSelector(state.threadStore.threadInfos),
   );
   return React.useCallback(
     (params: ExistingThreadInfoFinderParams): ?ThreadInfo => {
       if (!baseThreadInfo) {
         return null;
       }
 
       const realizedThreadInfo = threadInfos[baseThreadInfo.id];
       if (realizedThreadInfo) {
         return realizedThreadInfo;
       }
 
       if (!viewerID || !threadIsPending(baseThreadInfo.id)) {
         return baseThreadInfo;
       }
 
       invariant(
         threadTypeCanBePending(baseThreadInfo.type),
         `ThreadInfo has pending ID ${baseThreadInfo.id}, but type that ` +
           `should not be pending ${baseThreadInfo.type}`,
       );
 
       const { searching, userInfoInputArray } = params;
 
       const { sourceMessageID } = baseThreadInfo;
       const pendingThreadID = searching
-        ? getLocallyUniqueThreadID(
+        ? getPendingThreadID(
             pendingThreadType(userInfoInputArray.length),
             [...userInfoInputArray.map(user => user.id), viewerID],
             sourceMessageID,
           )
-        : getLocallyUniqueThreadID(
+        : getPendingThreadID(
             baseThreadInfo.type,
             baseThreadInfo.members.map(member => member.id),
             sourceMessageID,
           );
 
-      const realizedThreadID = locallyUniqueToRealizedThreadIDs.get(
-        pendingThreadID,
-      );
+      const realizedThreadID = pendingToRealizedThreadIDs.get(pendingThreadID);
       if (realizedThreadID && threadInfos[realizedThreadID]) {
         return threadInfos[realizedThreadID];
       }
 
       const updatedThread = searching
         ? createPendingThread({
             viewerID,
             threadType: pendingThreadType(userInfoInputArray.length),
             members: userInfoInputArray,
           })
         : baseThreadInfo;
       return {
         ...updatedThread,
         currentUser: getCurrentUser(updatedThread, viewerID, userInfos),
       };
     },
     [
       baseThreadInfo,
       threadInfos,
       viewerID,
-      locallyUniqueToRealizedThreadIDs,
+      pendingToRealizedThreadIDs,
       userInfos,
     ],
   );
 }
 
 type ThreadTypeParentRequirement = 'optional' | 'required' | 'disabled';
 function getThreadTypeParentRequirement(
   threadType: ThreadType,
 ): ThreadTypeParentRequirement {
   if (
     threadType === threadTypes.COMMUNITY_OPEN_SUBTHREAD ||
     threadType === threadTypes.COMMUNITY_OPEN_ANNOUNCEMENT_SUBTHREAD ||
     //threadType === threadTypes.COMMUNITY_SECRET_SUBTHREAD ||
     threadType === threadTypes.COMMUNITY_SECRET_ANNOUNCEMENT_SUBTHREAD ||
     threadType === threadTypes.SIDEBAR
   ) {
     return 'required';
   } else if (
     threadType === threadTypes.COMMUNITY_ROOT ||
     threadType === threadTypes.COMMUNITY_ANNOUNCEMENT_ROOT ||
     threadType === threadTypes.GENESIS ||
     threadType === threadTypes.PERSONAL ||
     threadType === threadTypes.PRIVATE
   ) {
     return 'disabled';
   } else {
     return 'optional';
   }
 }
 
 function threadMemberHasPermission(
   threadInfo: ServerThreadInfo | RawThreadInfo | ThreadInfo,
   memberID: string,
   permission: ThreadPermission,
 ): boolean {
   for (const member of threadInfo.members) {
     if (member.id !== memberID) {
       continue;
     }
     return permissionLookup(member.permissions, permission);
   }
   return false;
 }
 
 function useCanCreateSidebarFromMessage(
   threadInfo: ThreadInfo,
   messageInfo: ComposableMessageInfo | RobotextMessageInfo,
 ): boolean {
   const messageCreatorUserInfo = useSelector(
     state => state.userStore.userInfos[messageInfo.creator.id],
   );
 
   if (!messageInfo.id || threadInfo.sourceMessageID === messageInfo.id) {
     return false;
   }
 
   const messageCreatorRelationship = messageCreatorUserInfo?.relationshipStatus;
   const creatorRelationshipHasBlock =
     messageCreatorRelationship &&
     relationshipBlockedInEitherDirection(messageCreatorRelationship);
 
   const hasPermission = threadHasPermission(
     threadInfo,
     threadPermissions.CREATE_SIDEBARS,
   );
 
   return hasPermission && !creatorRelationshipHasBlock;
 }
 
 function useSidebarExistsOrCanBeCreated(
   threadInfo: ThreadInfo,
   messageItem: ChatMessageInfoItem,
 ): boolean {
   const canCreateSidebarFromMessage = useCanCreateSidebarFromMessage(
     threadInfo,
     messageItem.messageInfo,
   );
   return !!messageItem.threadCreatedFromMessage || canCreateSidebarFromMessage;
 }
 
 function checkIfDefaultMembersAreVoiced(threadInfo: ThreadInfo): boolean {
   const defaultRoleID = Object.keys(threadInfo.roles).find(
     roleID => threadInfo.roles[roleID].isDefault,
   );
   invariant(
     defaultRoleID !== undefined,
     'all threads should have a default role',
   );
   const defaultRole = threadInfo.roles[defaultRoleID];
   return !!defaultRole.permissions[threadPermissions.VOICED];
 }
 
 function draftKeyFromThreadID(threadID: string): string {
   return `${threadID}/message_composer`;
 }
 
 function getContainingThreadID(
   parentThreadInfo: ?ServerThreadInfo | RawThreadInfo | ThreadInfo,
   threadType: ThreadType,
 ): ?string {
   if (!parentThreadInfo) {
     return null;
   }
   if (threadType === threadTypes.SIDEBAR) {
     return parentThreadInfo.id;
   }
   if (!parentThreadInfo.containingThreadID) {
     return parentThreadInfo.id;
   }
   return parentThreadInfo.containingThreadID;
 }
 
 function getCommunity(
   parentThreadInfo: ?ServerThreadInfo | RawThreadInfo | ThreadInfo,
 ): ?string {
   if (!parentThreadInfo) {
     return null;
   }
   const { id, community, type } = parentThreadInfo;
   if (community !== null && community !== undefined) {
     return community;
   }
   if (threadTypeIsCommunityRoot(type)) {
     return id;
   }
   return null;
 }
 
 function getThreadListSearchResults(
   chatListData: $ReadOnlyArray<ChatThreadItem>,
   searchText: string,
   threadFilter: ThreadInfo => boolean,
   threadSearchResults: $ReadOnlySet<string>,
   usersSearchResults: $ReadOnlyArray<GlobalAccountUserInfo>,
   viewerID: ?string,
 ): $ReadOnlyArray<ChatThreadItem> {
   if (!searchText) {
     return chatListData.filter(
       item =>
         threadIsTopLevel(item.threadInfo) && threadFilter(item.threadInfo),
     );
   }
 
   const privateThreads = [];
   const personalThreads = [];
   const otherThreads = [];
   for (const item of chatListData) {
     if (!threadSearchResults.has(item.threadInfo.id)) {
       continue;
     }
     if (item.threadInfo.type === threadTypes.PRIVATE) {
       privateThreads.push({ ...item, sidebars: [] });
     } else if (item.threadInfo.type === threadTypes.PERSONAL) {
       personalThreads.push({ ...item, sidebars: [] });
     } else {
       otherThreads.push({ ...item, sidebars: [] });
     }
   }
 
   const chatItems = [...privateThreads, ...personalThreads, ...otherThreads];
   if (viewerID) {
     chatItems.push(
       ...usersSearchResults.map(user =>
         createPendingThreadItem(viewerID, user),
       ),
     );
   }
   return chatItems;
 }
 
 type ThreadListSearchResult = {
   +threadSearchResults: $ReadOnlySet<string>,
   +usersSearchResults: $ReadOnlyArray<GlobalAccountUserInfo>,
 };
 function useThreadListSearch(
   chatListData: $ReadOnlyArray<ChatThreadItem>,
   searchText: string,
   viewerID: ?string,
 ): ThreadListSearchResult {
   const callSearchUsers = useServerCall(searchUserCall);
   const usersWithPersonalThread = useSelector(usersWithPersonalThreadSelector);
   const searchUsers = React.useCallback(
     async (usernamePrefix: string) => {
       if (usernamePrefix.length === 0) {
         return [];
       }
 
       const { userInfos } = await callSearchUsers(usernamePrefix);
       return userInfos.filter(
         info => !usersWithPersonalThread.has(info.id) && info.id !== viewerID,
       );
     },
     [callSearchUsers, usersWithPersonalThread, viewerID],
   );
 
   const [threadSearchResults, setThreadSearchResults] = React.useState(
     new Set(),
   );
   const [usersSearchResults, setUsersSearchResults] = React.useState([]);
   const threadSearchIndex = useSelector(threadSearchIndexSelector);
   React.useEffect(() => {
     (async () => {
       const results = threadSearchIndex.getSearchResults(searchText);
       setThreadSearchResults(new Set(results));
       const usersResults = await searchUsers(searchText);
       setUsersSearchResults(usersResults);
     })();
   }, [searchText, chatListData, threadSearchIndex, searchUsers]);
 
   return { threadSearchResults, usersSearchResults };
 }
 
 function removeMemberFromThread(
   threadInfo: ThreadInfo,
   memberInfo: RelativeMemberInfo,
   dispatchActionPromise: DispatchActionPromise,
   removeUserFromThreadServerCall: (
     threadID: string,
     memberIDs: $ReadOnlyArray<string>,
   ) => Promise<ChangeThreadSettingsPayload>,
 ) {
   const customKeyName = `${removeUsersFromThreadActionTypes.started}:${memberInfo.id}`;
   dispatchActionPromise(
     removeUsersFromThreadActionTypes,
     removeUserFromThreadServerCall(threadInfo.id, [memberInfo.id]),
     { customKeyName },
   );
 }
 
 function switchMemberAdminRoleInThread(
   threadInfo: ThreadInfo,
   memberInfo: RelativeMemberInfo,
   isCurrentlyAdmin: boolean,
   dispatchActionPromise: DispatchActionPromise,
   changeUserRoleServerCall: (
     threadID: string,
     memberIDs: $ReadOnlyArray<string>,
     newRole: string,
   ) => Promise<ChangeThreadSettingsPayload>,
 ) {
   let newRole = null;
   for (const roleID in threadInfo.roles) {
     const role = threadInfo.roles[roleID];
     if (isCurrentlyAdmin && role.isDefault) {
       newRole = role.id;
       break;
     } else if (!isCurrentlyAdmin && roleIsAdminRole(role)) {
       newRole = role.id;
       break;
     }
   }
   invariant(newRole !== null, 'Could not find new role');
 
   const customKeyName = `${changeThreadMemberRolesActionTypes.started}:${memberInfo.id}`;
   dispatchActionPromise(
     changeThreadMemberRolesActionTypes,
     changeUserRoleServerCall(threadInfo.id, [memberInfo.id], newRole),
     { customKeyName },
   );
 }
 
 function getAvailableThreadMemberActions(
   memberInfo: RelativeMemberInfo,
   threadInfo: ThreadInfo,
   canEdit: ?boolean = true,
 ): $ReadOnlyArray<'remove_user' | 'remove_admin' | 'make_admin'> {
   const role = memberInfo.role;
   if (!canEdit || !role) {
     return [];
   }
 
   const canRemoveMembers = threadHasPermission(
     threadInfo,
     threadPermissions.REMOVE_MEMBERS,
   );
   const canChangeRoles = threadHasPermission(
     threadInfo,
     threadPermissions.CHANGE_ROLE,
   );
 
   const result = [];
   if (
     canRemoveMembers &&
     !memberInfo.isViewer &&
     (canChangeRoles || threadInfo.roles[role]?.isDefault)
   ) {
     result.push('remove_user');
   }
 
   if (canChangeRoles && memberInfo.username && threadHasAdminRole(threadInfo)) {
     result.push(
       memberIsAdmin(memberInfo, threadInfo) ? 'remove_admin' : 'make_admin',
     );
   }
 
   return result;
 }
 
 export {
   colorIsDark,
   generateRandomColor,
   generatePendingThreadColor,
   threadHasPermission,
   viewerIsMember,
   threadInChatList,
   threadIsTopLevel,
   threadIsChannel,
   threadIsSidebar,
   threadInBackgroundChatList,
   threadInHomeChatList,
   threadIsInHome,
   threadInFilterList,
   userIsMember,
   threadActualMembers,
   threadIsGroupChat,
   threadIsPending,
   getSingleOtherUser,
-  getLocallyUniqueThreadID,
-  locallyUniqueThreadIDRegex,
-  parseLocallyUniqueThreadID,
+  getPendingThreadID,
+  pendingThreadIDRegex,
+  parsePendingThreadID,
   createPendingThread,
   createPendingThreadItem,
   createPendingSidebar,
   pendingThreadType,
   createRealThreadFromPendingThread,
   getCurrentUser,
   threadFrozenDueToBlock,
   threadFrozenDueToViewerBlock,
   rawThreadInfoFromServerThreadInfo,
   filterThreadEditDetailedPermissions,
   robotextName,
   threadInfoFromRawThreadInfo,
   rawThreadInfoFromThreadInfo,
   threadTypeDescriptions,
   usersInThreadInfo,
   memberIsAdmin,
   memberHasAdminPowers,
   roleIsAdminRole,
   threadHasAdminRole,
   identifyInvalidatedThreads,
   permissionsDisabledByBlock,
   emptyItemText,
   threadSearchText,
   threadNoun,
   threadLabel,
   useWatchThread,
   useExistingThreadInfoFinder,
   getThreadTypeParentRequirement,
   threadMemberHasPermission,
   useCanCreateSidebarFromMessage,
   useSidebarExistsOrCanBeCreated,
   checkIfDefaultMembersAreVoiced,
   draftKeyFromThreadID,
   threadTypeCanBePending,
   getContainingThreadID,
   getCommunity,
   getThreadListSearchResults,
   useThreadListSearch,
   removeMemberFromThread,
   switchMemberAdminRoleInThread,
   getAvailableThreadMemberActions,
   selectedThreadColors,
 };
diff --git a/lib/shared/thread-utils.test.js b/lib/shared/thread-utils.test.js
index 5c238c857..a943d91ab 100644
--- a/lib/shared/thread-utils.test.js
+++ b/lib/shared/thread-utils.test.js
@@ -1,60 +1,58 @@
 // @flow
 
 import { threadTypes } from '../types/thread-types';
-import { parseLocallyUniqueThreadID } from './thread-utils';
+import { parsePendingThreadID } from './thread-utils';
 
-describe('parseLocallyUniqueThreadID(pendingThreadID: string)', () => {
+describe('parsePendingThreadID(pendingThreadID: string)', () => {
   it('should return correct data for real pending sidebar ID', () => {
     const sidebarResult = {
       threadType: threadTypes.SIDEBAR,
       memberIDs: [],
       sourceMessageID: '12345',
     };
-    expect(parseLocallyUniqueThreadID('pending/sidebar/12345')).toStrictEqual(
+    expect(parsePendingThreadID('pending/sidebar/12345')).toStrictEqual(
       sidebarResult,
     );
   });
 
   it('should return correct data for real pending sidebar ID', () => {
     const pendingPersonalResult = {
       threadType: threadTypes.PERSONAL,
       memberIDs: ['83810', '86622'],
       sourceMessageID: null,
     };
-    expect(
-      parseLocallyUniqueThreadID('pending/type6/83810+86622'),
-    ).toStrictEqual(pendingPersonalResult);
+    expect(parsePendingThreadID('pending/type6/83810+86622')).toStrictEqual(
+      pendingPersonalResult,
+    );
 
     const pendingCommunityOpenResult = {
       threadType: threadTypes.COMMUNITY_OPEN_SUBTHREAD,
       memberIDs: ['83810', '86622', '83889'],
       sourceMessageID: null,
     };
     expect(
-      parseLocallyUniqueThreadID('pending/type3/83810+86622+83889'),
+      parsePendingThreadID('pending/type3/83810+86622+83889'),
     ).toStrictEqual(pendingCommunityOpenResult);
   });
 
   it('should return null when there are missing information in ID', () => {
-    expect(parseLocallyUniqueThreadID('pending/type4/')).toBeNull();
-    expect(parseLocallyUniqueThreadID('type12/83810+86622')).toBeNull();
-    expect(parseLocallyUniqueThreadID('pending/83810')).toBeNull();
-    expect(parseLocallyUniqueThreadID('pending')).toBeNull();
-    expect(parseLocallyUniqueThreadID('')).toBeNull();
-    expect(parseLocallyUniqueThreadID('pending/something/12345')).toBeNull();
+    expect(parsePendingThreadID('pending/type4/')).toBeNull();
+    expect(parsePendingThreadID('type12/83810+86622')).toBeNull();
+    expect(parsePendingThreadID('pending/83810')).toBeNull();
+    expect(parsePendingThreadID('pending')).toBeNull();
+    expect(parsePendingThreadID('')).toBeNull();
+    expect(parsePendingThreadID('pending/something/12345')).toBeNull();
   });
 
   it('should return null when the format is invalid', () => {
-    expect(parseLocallyUniqueThreadID('someothertext/type1/12345')).toBeNull();
-    expect(
-      parseLocallyUniqueThreadID('pending/type6/12312+++11+12'),
-    ).toBeNull();
-    expect(parseLocallyUniqueThreadID('pending/type3/83810+')).toBeNull();
+    expect(parsePendingThreadID('someothertext/type1/12345')).toBeNull();
+    expect(parsePendingThreadID('pending/type6/12312+++11+12')).toBeNull();
+    expect(parsePendingThreadID('pending/type3/83810+')).toBeNull();
   });
 
   it('should throw invariant violation when thread type is invalid ', () => {
-    expect(() =>
-      parseLocallyUniqueThreadID('pending/type123/12345'),
-    ).toThrowError('number is not ThreadType enum');
+    expect(() => parsePendingThreadID('pending/type123/12345')).toThrowError(
+      'number is not ThreadType enum',
+    );
   });
 });
diff --git a/lib/utils/url-utils.js b/lib/utils/url-utils.js
index 6325aa08c..f5ba8c76e 100644
--- a/lib/utils/url-utils.js
+++ b/lib/utils/url-utils.js
@@ -1,98 +1,98 @@
 // @flow
 
 import urlParseLax from 'url-parse-lax';
 
-import { locallyUniqueThreadIDRegex } from '../shared/thread-utils';
+import { pendingThreadIDRegex } from '../shared/thread-utils';
 
 export type URLInfo = {
   +year?: number,
   +month?: number, // 1-indexed
   +verify?: string,
   +calendar?: boolean,
   +chat?: boolean,
   +apps?: boolean,
   +thread?: string,
   +settings?: 'account' | 'danger-zone',
   +threadCreation?: boolean,
   +selectedUserList?: $ReadOnlyArray<string>,
   ...
 };
 
 // We use groups to capture parts of the URL and any changes
 // to regexes must be reflected in infoFromURL.
 const yearRegex = new RegExp('(/|^)year/([0-9]+)(/|$)', 'i');
 const monthRegex = new RegExp('(/|^)month/([0-9]+)(/|$)', 'i');
 const threadRegex = new RegExp('(/|^)thread/([0-9]+)(/|$)', 'i');
 const verifyRegex = new RegExp('(/|^)verify/([a-f0-9]+)(/|$)', 'i');
 const calendarRegex = new RegExp('(/|^)calendar(/|$)', 'i');
 const chatRegex = new RegExp('(/|^)chat(/|$)', 'i');
 const appsRegex = new RegExp('(/|^)apps(/|$)', 'i');
 const accountSettingsRegex = new RegExp('(/|^)settings/account(/|$)', 'i');
 const dangerZoneRegex = new RegExp('(/|^)settings/danger-zone(/|$)', 'i');
 const threadPendingRegex = new RegExp(
-  `(/|^)thread/(${locallyUniqueThreadIDRegex})(/|$)`,
+  `(/|^)thread/(${pendingThreadIDRegex})(/|$)`,
   'i',
 );
 const threadCreationRegex = new RegExp(
   '(/|^)thread/new(/([0-9]+([+][0-9]+)*))?(/|$)',
   'i',
 );
 
 function infoFromURL(url: string): URLInfo {
   const yearMatches = yearRegex.exec(url);
   const monthMatches = monthRegex.exec(url);
   const threadMatches = threadRegex.exec(url);
   const verifyMatches = verifyRegex.exec(url);
   const calendarTest = calendarRegex.test(url);
   const chatTest = chatRegex.test(url);
   const appsTest = appsRegex.test(url);
   const accountSettingsTest = accountSettingsRegex.test(url);
   const dangerZoneTest = dangerZoneRegex.test(url);
   const threadPendingMatches = threadPendingRegex.exec(url);
   const threadCreateMatches = threadCreationRegex.exec(url);
 
   const returnObj = {};
   if (yearMatches) {
     returnObj.year = parseInt(yearMatches[2], 10);
   }
   if (monthMatches) {
     const month = parseInt(monthMatches[2], 10);
     if (month < 1 || month > 12) {
       throw new Error('invalid_month');
     }
     returnObj.month = month;
   }
   if (threadMatches) {
     returnObj.thread = threadMatches[2];
   }
   if (threadPendingMatches) {
     returnObj.thread = threadPendingMatches[2];
   }
   if (threadCreateMatches) {
     returnObj.threadCreation = true;
     returnObj.selectedUserList = threadCreateMatches[3]?.split('+') ?? [];
   }
   if (verifyMatches) {
     returnObj.verify = verifyMatches[2];
   }
   if (calendarTest) {
     returnObj.calendar = true;
   } else if (chatTest) {
     returnObj.chat = true;
   } else if (appsTest) {
     returnObj.apps = true;
   } else if (accountSettingsTest) {
     returnObj.settings = 'account';
   } else if (dangerZoneTest) {
     returnObj.settings = 'danger-zone';
   }
   return returnObj;
 }
 
 function normalizeURL(url: string): string {
   return urlParseLax(url).href;
 }
 
 const setURLPrefix = 'SET_URL_PREFIX';
 
 export { infoFromURL, normalizeURL, setURLPrefix };
diff --git a/native/chat/thread-draft-updater.react.js b/native/chat/thread-draft-updater.react.js
index 267901151..555e702ae 100644
--- a/native/chat/thread-draft-updater.react.js
+++ b/native/chat/thread-draft-updater.react.js
@@ -1,52 +1,49 @@
 // @flow
 
 import invariant from 'invariant';
 import * as React from 'react';
 
-import { locallyUniqueToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
+import { pendingToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
 import { draftKeyFromThreadID } from 'lib/shared/thread-utils';
 
 import { useDrafts } from '../data/core-data';
 import { useSelector } from '../redux/redux-utils';
 import type { AppState } from '../redux/state-types';
 
 const ThreadDraftUpdater: React.ComponentType<{}> = React.memo<{}>(
   function ThreadDraftUpdater() {
-    const locallyUniqueToRealizedThreadIDs = useSelector((state: AppState) =>
-      locallyUniqueToRealizedThreadIDsSelector(state.threadStore.threadInfos),
+    const pendingToRealizedThreadIDs = useSelector((state: AppState) =>
+      pendingToRealizedThreadIDsSelector(state.threadStore.threadInfos),
     );
     const drafts = useDrafts();
 
     const cachedThreadIDsRef = React.useRef();
     if (!cachedThreadIDsRef.current) {
       const newCachedThreadIDs = new Set();
-      for (const realizedThreadID of locallyUniqueToRealizedThreadIDs.values()) {
+      for (const realizedThreadID of pendingToRealizedThreadIDs.values()) {
         newCachedThreadIDs.add(realizedThreadID);
       }
       cachedThreadIDsRef.current = newCachedThreadIDs;
     }
 
     const { moveDraft } = drafts;
     React.useEffect(() => {
-      for (const [
-        locallyUniqueThreadID,
-        threadID,
-      ] of locallyUniqueToRealizedThreadIDs) {
+      for (const [pendingThreadID, threadID] of pendingToRealizedThreadIDs) {
         const cachedThreadIDs = cachedThreadIDsRef.current;
         invariant(cachedThreadIDs, 'should be set');
         if (cachedThreadIDs.has(threadID)) {
           continue;
         }
         moveDraft(
-          draftKeyFromThreadID(locallyUniqueThreadID),
+          draftKeyFromThreadID(pendingThreadID),
           draftKeyFromThreadID(threadID),
         );
         cachedThreadIDs.add(threadID);
       }
-    }, [locallyUniqueToRealizedThreadIDs, moveDraft]);
+    }, [pendingToRealizedThreadIDs, moveDraft]);
     return null;
   },
 );
 ThreadDraftUpdater.displayName = 'ThreadDraftUpdater';
 
 export default ThreadDraftUpdater;
diff --git a/web/input/input-state-container.react.js b/web/input/input-state-container.react.js
index 34fd31424..5eb82a275 100644
--- a/web/input/input-state-container.react.js
+++ b/web/input/input-state-container.react.js
@@ -1,1298 +1,1298 @@
 // @flow
 
 import { detect as detectBrowser } from 'detect-browser';
 import invariant from 'invariant';
 import _groupBy from 'lodash/fp/groupBy';
 import _keyBy from 'lodash/fp/keyBy';
 import _omit from 'lodash/fp/omit';
 import _partition from 'lodash/fp/partition';
 import _sortBy from 'lodash/fp/sortBy';
 import _memoize from 'lodash/memoize';
 import * as React from 'react';
 import { useDispatch } from 'react-redux';
 import { createSelector } from 'reselect';
 
 import {
   createLocalMessageActionType,
   sendMultimediaMessageActionTypes,
   sendMultimediaMessage,
   sendTextMessageActionTypes,
   sendTextMessage,
 } from 'lib/actions/message-actions';
 import { queueReportsActionType } from 'lib/actions/report-actions';
 import { newThread } from 'lib/actions/thread-actions';
 import {
   uploadMultimedia,
   updateMultimediaMessageMediaActionType,
   deleteUpload,
   type MultimediaUploadCallbacks,
   type MultimediaUploadExtras,
 } from 'lib/actions/upload-actions';
 import { getNextLocalUploadID } from 'lib/media/media-utils';
-import { locallyUniqueToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
+import { pendingToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
 import {
   createMediaMessageInfo,
   localIDPrefix,
 } from 'lib/shared/message-utils';
 import {
   createRealThreadFromPendingThread,
   threadIsPending,
 } from 'lib/shared/thread-utils';
 import type { CalendarQuery } from 'lib/types/entry-types';
 import type {
   UploadMultimediaResult,
   MediaMissionStep,
   MediaMissionFailure,
   MediaMissionResult,
   MediaMission,
 } from 'lib/types/media-types';
 import {
   messageTypes,
   type RawMessageInfo,
   type RawMultimediaMessageInfo,
   type SendMessageResult,
   type SendMessagePayload,
 } from 'lib/types/message-types';
 import type { RawImagesMessageInfo } from 'lib/types/messages/images';
 import type { RawMediaMessageInfo } from 'lib/types/messages/media';
 import type { RawTextMessageInfo } from 'lib/types/messages/text';
 import type { Dispatch } from 'lib/types/redux-types';
 import { reportTypes } from 'lib/types/report-types';
 import type {
   ClientNewThreadRequest,
   NewThreadResult,
   ThreadInfo,
 } from 'lib/types/thread-types';
 import {
   type DispatchActionPromise,
   useServerCall,
   useDispatchActionPromise,
 } from 'lib/utils/action-utils';
 import { getConfig } from 'lib/utils/config';
 import { getMessageForException, cloneError } from 'lib/utils/errors';
 
 import { validateFile, preloadImage } from '../media/media-utils';
 import InvalidUploadModal from '../modals/chat/invalid-upload.react';
 import { useModalContext } from '../modals/modal-provider.react';
 import { useSelector } from '../redux/redux-utils';
 import { nonThreadCalendarQuery } from '../selectors/nav-selectors';
 import { type PendingMultimediaUpload, InputStateContext } from './input-state';
 
 type BaseProps = {
   +children: React.Node,
 };
 type Props = {
   ...BaseProps,
   +activeChatThreadID: ?string,
   +viewerID: ?string,
   +messageStoreMessages: { +[id: string]: RawMessageInfo },
   +exifRotate: boolean,
-  +locallyUniqueRealizedThreadIDs: $ReadOnlyMap<string, string>,
+  +pendingRealizedThreadIDs: $ReadOnlyMap<string, string>,
   +dispatch: Dispatch,
   +dispatchActionPromise: DispatchActionPromise,
   +calendarQuery: () => CalendarQuery,
   +uploadMultimedia: (
     multimedia: Object,
     extras: MultimediaUploadExtras,
     callbacks: MultimediaUploadCallbacks,
   ) => Promise<UploadMultimediaResult>,
   +deleteUpload: (id: string) => Promise<void>,
   +sendMultimediaMessage: (
     threadID: string,
     localID: string,
     mediaIDs: $ReadOnlyArray<string>,
   ) => Promise<SendMessageResult>,
   +sendTextMessage: (
     threadID: string,
     localID: string,
     text: string,
   ) => Promise<SendMessageResult>,
   +newThread: (request: ClientNewThreadRequest) => Promise<NewThreadResult>,
   +pushModal: (modal: React.Node) => void,
   +sendCallbacks: $ReadOnlyArray<() => mixed>,
   +registerSendCallback: (() => mixed) => void,
   +unregisterSendCallback: (() => mixed) => void,
 };
 type State = {
   +pendingUploads: {
     [threadID: string]: { [localUploadID: string]: PendingMultimediaUpload },
   },
   +drafts: { [threadID: string]: string },
 };
 class InputStateContainer extends React.PureComponent<Props, State> {
   state: State = {
     pendingUploads: {},
     drafts: {},
   };
   replyCallbacks: Array<(message: string) => void> = [];
   pendingThreadCreations = new Map<string, Promise<string>>();
 
   static reassignToRealizedThreads<T>(
     state: { +[threadID: string]: T },
     props: Props,
   ): ?{ [threadID: string]: T } {
     const newState = {};
     let updated = false;
     for (const threadID in state) {
       const newThreadID =
-        props.locallyUniqueRealizedThreadIDs.get(threadID) ?? threadID;
+        props.pendingRealizedThreadIDs.get(threadID) ?? threadID;
       if (newThreadID !== threadID) {
         updated = true;
       }
       newState[newThreadID] = state[threadID];
     }
     return updated ? newState : null;
   }
 
   static getDerivedStateFromProps(props: Props, state: State) {
     const drafts = InputStateContainer.reassignToRealizedThreads(
       state.drafts,
       props,
     );
     const pendingUploads = InputStateContainer.reassignToRealizedThreads(
       state.pendingUploads,
       props,
     );
 
     if (!drafts && !pendingUploads) {
       return null;
     }
 
     const stateUpdate = {};
     if (drafts) {
       stateUpdate.drafts = drafts;
     }
     if (pendingUploads) {
       stateUpdate.pendingUploads = pendingUploads;
     }
     return stateUpdate;
   }
 
   static completedMessageIDs(state: State) {
     const completed = new Map();
     for (const threadID in state.pendingUploads) {
       const pendingUploads = state.pendingUploads[threadID];
       for (const localUploadID in pendingUploads) {
         const upload = pendingUploads[localUploadID];
         const { messageID, serverID, failed } = upload;
         if (!messageID || !messageID.startsWith(localIDPrefix)) {
           continue;
         }
         if (!serverID || failed) {
           completed.set(messageID, false);
           continue;
         }
         if (completed.get(messageID) === undefined) {
           completed.set(messageID, true);
         }
       }
     }
     const messageIDs = new Set();
     for (const [messageID, isCompleted] of completed) {
       if (isCompleted) {
         messageIDs.add(messageID);
       }
     }
     return messageIDs;
   }
 
   componentDidUpdate(prevProps: Props, prevState: State) {
     if (this.props.viewerID !== prevProps.viewerID) {
       this.setState({ pendingUploads: {} });
       return;
     }
 
     const previouslyAssignedMessageIDs = new Set();
     for (const threadID in prevState.pendingUploads) {
       const pendingUploads = prevState.pendingUploads[threadID];
       for (const localUploadID in pendingUploads) {
         const { messageID } = pendingUploads[localUploadID];
         if (messageID) {
           previouslyAssignedMessageIDs.add(messageID);
         }
       }
     }
 
     const newlyAssignedUploads = new Map();
     for (const threadID in this.state.pendingUploads) {
       const pendingUploads = this.state.pendingUploads[threadID];
       for (const localUploadID in pendingUploads) {
         const upload = pendingUploads[localUploadID];
         const { messageID } = upload;
         if (
           !messageID ||
           !messageID.startsWith(localIDPrefix) ||
           previouslyAssignedMessageIDs.has(messageID)
         ) {
           continue;
         }
         let assignedUploads = newlyAssignedUploads.get(messageID);
         if (!assignedUploads) {
           assignedUploads = { threadID, uploads: [] };
           newlyAssignedUploads.set(messageID, assignedUploads);
         }
         assignedUploads.uploads.push(upload);
       }
     }
 
     const newMessageInfos = new Map();
     for (const [messageID, assignedUploads] of newlyAssignedUploads) {
       const { uploads, threadID } = assignedUploads;
       const creatorID = this.props.viewerID;
       invariant(creatorID, 'need viewer ID in order to send a message');
       const media = uploads.map(
         ({ localID, serverID, uri, mediaType, dimensions }) => {
           // We can get into this state where dimensions are null if the user is
           // uploading a file type that the browser can't render. In that case
           // we fake the dimensions here while we wait for the server to tell us
           // the true dimensions. We actually don't use the dimensions on the
           // web side currently, but if we ever change that (for instance if we
           // want to render a properly sized loading overlay like we do on
           // native), 0,0 is probably a good default.
           const shimmedDimensions = dimensions
             ? dimensions
             : { height: 0, width: 0 };
           invariant(
             mediaType === 'photo',
             "web InputStateContainer can't handle video",
           );
           return {
             id: serverID ? serverID : localID,
             uri,
             type: 'photo',
             dimensions: shimmedDimensions,
           };
         },
       );
       const messageInfo = createMediaMessageInfo({
         localID: messageID,
         threadID,
         creatorID,
         media,
       });
       newMessageInfos.set(messageID, messageInfo);
     }
 
     const currentlyCompleted = InputStateContainer.completedMessageIDs(
       this.state,
     );
     const previouslyCompleted = InputStateContainer.completedMessageIDs(
       prevState,
     );
     for (const messageID of currentlyCompleted) {
       if (previouslyCompleted.has(messageID)) {
         continue;
       }
       let rawMessageInfo = newMessageInfos.get(messageID);
       if (rawMessageInfo) {
         newMessageInfos.delete(messageID);
       } else {
         rawMessageInfo = this.getRawMultimediaMessageInfo(messageID);
       }
       this.sendMultimediaMessage(rawMessageInfo);
     }
 
     for (const [, messageInfo] of newMessageInfos) {
       this.props.dispatch({
         type: createLocalMessageActionType,
         payload: messageInfo,
       });
     }
   }
 
   getRawMultimediaMessageInfo(
     localMessageID: string,
   ): RawMultimediaMessageInfo {
     const rawMessageInfo = this.props.messageStoreMessages[localMessageID];
     invariant(rawMessageInfo, `rawMessageInfo ${localMessageID} should exist`);
     invariant(
       rawMessageInfo.type === messageTypes.IMAGES ||
         rawMessageInfo.type === messageTypes.MULTIMEDIA,
       `rawMessageInfo ${localMessageID} should be multimedia`,
     );
     return rawMessageInfo;
   }
 
   async sendMultimediaMessage(messageInfo: RawMultimediaMessageInfo) {
     if (!threadIsPending(messageInfo.threadID)) {
       this.props.dispatchActionPromise(
         sendMultimediaMessageActionTypes,
         this.sendMultimediaMessageAction(messageInfo),
         undefined,
         messageInfo,
       );
       return;
     }
 
     this.props.dispatch({
       type: sendMultimediaMessageActionTypes.started,
       payload: messageInfo,
     });
 
     let newThreadID = null;
     try {
       const threadCreationPromise = this.pendingThreadCreations.get(
         messageInfo.threadID,
       );
       if (!threadCreationPromise) {
         // When we create or retry multimedia message, we add a promise to
         // pendingThreadCreations map. This promise can be removed in
         // sendMultimediaMessage and sendTextMessage methods. When any of these
         // method remove the promise, it has to be settled. If the promise was
         // fulfilled, this method would be called with realized thread, so we
         // can conclude that the promise was rejected. We don't have enough info
         // here to retry the thread creation, but we can mark the message as
         // failed. Then the retry will be possible and promise will be created
         // again.
         throw new Error('Thread creation failed');
       }
       newThreadID = await threadCreationPromise;
     } catch (e) {
       const copy = cloneError(e);
       copy.localID = messageInfo.localID;
       copy.threadID = messageInfo.threadID;
       this.props.dispatch({
         type: sendMultimediaMessageActionTypes.failed,
         payload: copy,
         error: true,
       });
       return;
     } finally {
       this.pendingThreadCreations.delete(messageInfo.threadID);
     }
 
     const newMessageInfo = {
       ...messageInfo,
       threadID: newThreadID,
       time: Date.now(),
     };
     this.props.dispatchActionPromise(
       sendMultimediaMessageActionTypes,
       this.sendMultimediaMessageAction(newMessageInfo),
       undefined,
       newMessageInfo,
     );
   }
 
   async sendMultimediaMessageAction(
     messageInfo: RawMultimediaMessageInfo,
   ): Promise<SendMessagePayload> {
     const { localID, threadID } = messageInfo;
     invariant(
       localID !== null && localID !== undefined,
       'localID should be set',
     );
     const mediaIDs = [];
     for (const { id } of messageInfo.media) {
       mediaIDs.push(id);
     }
     try {
       const result = await this.props.sendMultimediaMessage(
         threadID,
         localID,
         mediaIDs,
       );
       this.setState(prevState => {
         const newThreadID = this.getRealizedOrPendingThreadID(threadID);
         const prevUploads = prevState.pendingUploads[newThreadID];
         const newUploads = {};
         for (const localUploadID in prevUploads) {
           const upload = prevUploads[localUploadID];
           if (upload.messageID !== localID) {
             newUploads[localUploadID] = upload;
           } else if (!upload.uriIsReal) {
             newUploads[localUploadID] = {
               ...upload,
               messageID: result.id,
             };
           }
         }
         return {
           pendingUploads: {
             ...prevState.pendingUploads,
             [newThreadID]: newUploads,
           },
         };
       });
       return {
         localID,
         serverID: result.id,
         threadID,
         time: result.time,
         interface: result.interface,
       };
     } catch (e) {
       const copy = cloneError(e);
       copy.localID = localID;
       copy.threadID = threadID;
       throw copy;
     }
   }
 
   async startThreadCreation(threadInfo: ThreadInfo): Promise<string> {
     if (!threadIsPending(threadInfo.id)) {
       return threadInfo.id;
     }
     let threadCreationPromise = this.pendingThreadCreations.get(threadInfo.id);
     if (!threadCreationPromise) {
       const calendarQuery = this.props.calendarQuery();
       threadCreationPromise = createRealThreadFromPendingThread({
         threadInfo,
         dispatchActionPromise: this.props.dispatchActionPromise,
         createNewThread: this.props.newThread,
         sourceMessageID: threadInfo.sourceMessageID,
         viewerID: this.props.viewerID,
         calendarQuery,
       });
       this.pendingThreadCreations.set(threadInfo.id, threadCreationPromise);
     }
     return threadCreationPromise;
   }
 
   inputStateSelector = _memoize((threadID: string) =>
     createSelector(
       (state: State) => state.pendingUploads[threadID],
       (state: State) => state.drafts[threadID],
       (
         pendingUploads: ?{ [localUploadID: string]: PendingMultimediaUpload },
         draft: ?string,
       ) => {
         let threadPendingUploads = [];
         const assignedUploads = {};
         if (pendingUploads) {
           const [uploadsWithMessageIDs, uploadsWithoutMessageIDs] = _partition(
             'messageID',
           )(pendingUploads);
           threadPendingUploads = _sortBy('localID')(uploadsWithoutMessageIDs);
           const threadAssignedUploads = _groupBy('messageID')(
             uploadsWithMessageIDs,
           );
           for (const messageID in threadAssignedUploads) {
             // lodash libdefs don't return $ReadOnlyArray
             assignedUploads[messageID] = [...threadAssignedUploads[messageID]];
           }
         }
         return {
           pendingUploads: threadPendingUploads,
           assignedUploads,
           draft: draft ? draft : '',
           appendFiles: (files: $ReadOnlyArray<File>) =>
             this.appendFiles(threadID, files),
           cancelPendingUpload: (localUploadID: string) =>
             this.cancelPendingUpload(threadID, localUploadID),
           sendTextMessage: (
             messageInfo: RawTextMessageInfo,
             threadInfo: ThreadInfo,
           ) => this.sendTextMessage(messageInfo, threadInfo),
           createMultimediaMessage: (localID: number, threadInfo: ThreadInfo) =>
             this.createMultimediaMessage(localID, threadInfo),
           setDraft: (newDraft: string) => this.setDraft(threadID, newDraft),
           messageHasUploadFailure: (localMessageID: string) =>
             this.messageHasUploadFailure(assignedUploads[localMessageID]),
           retryMultimediaMessage: (
             localMessageID: string,
             threadInfo: ThreadInfo,
           ) =>
             this.retryMultimediaMessage(
               localMessageID,
               threadInfo,
               assignedUploads[localMessageID],
             ),
           addReply: (message: string) => this.addReply(message),
           addReplyListener: this.addReplyListener,
           removeReplyListener: this.removeReplyListener,
           registerSendCallback: this.props.registerSendCallback,
           unregisterSendCallback: this.props.unregisterSendCallback,
         };
       },
     ),
   );
 
   getRealizedOrPendingThreadID(threadID: string): string {
-    return this.props.locallyUniqueRealizedThreadIDs.get(threadID) ?? threadID;
+    return this.props.pendingRealizedThreadIDs.get(threadID) ?? threadID;
   }
 
   async appendFiles(
     threadID: string,
     files: $ReadOnlyArray<File>,
   ): Promise<boolean> {
     const selectionTime = Date.now();
     const { pushModal } = this.props;
 
     const appendResults = await Promise.all(
       files.map(file => this.appendFile(file, selectionTime)),
     );
 
     if (appendResults.some(({ result }) => !result.success)) {
       pushModal(<InvalidUploadModal />);
 
       const time = Date.now() - selectionTime;
       const reports = [];
       for (const appendResult of appendResults) {
         const { steps } = appendResult;
         let { result } = appendResult;
         let uploadLocalID;
         if (result.success) {
           uploadLocalID = result.pendingUpload.localID;
           result = { success: false, reason: 'web_sibling_validation_failed' };
         }
         const mediaMission = { steps, result, userTime: time, totalTime: time };
         reports.push({ mediaMission, uploadLocalID });
       }
       this.queueMediaMissionReports(reports);
 
       return false;
     }
 
     const newUploads = appendResults.map(({ result }) => {
       invariant(result.success, 'any failed validation should be caught above');
       return result.pendingUpload;
     });
 
     const newUploadsObject = _keyBy('localID')(newUploads);
     this.setState(
       prevState => {
         const newThreadID = this.getRealizedOrPendingThreadID(threadID);
         const prevUploads = prevState.pendingUploads[newThreadID];
         const mergedUploads = prevUploads
           ? { ...prevUploads, ...newUploadsObject }
           : newUploadsObject;
         return {
           pendingUploads: {
             ...prevState.pendingUploads,
             [newThreadID]: mergedUploads,
           },
         };
       },
       () => this.uploadFiles(threadID, newUploads),
     );
     return true;
   }
 
   async appendFile(
     file: File,
     selectTime: number,
   ): Promise<{
     steps: $ReadOnlyArray<MediaMissionStep>,
     result:
       | MediaMissionFailure
       | { success: true, pendingUpload: PendingMultimediaUpload },
   }> {
     const steps = [
       {
         step: 'web_selection',
         filename: file.name,
         size: file.size,
         mime: file.type,
         selectTime,
       },
     ];
 
     let response;
     const validationStart = Date.now();
     try {
       response = await validateFile(file, this.props.exifRotate);
     } catch (e) {
       return {
         steps,
         result: {
           success: false,
           reason: 'processing_exception',
           time: Date.now() - validationStart,
           exceptionMessage: getMessageForException(e),
         },
       };
     }
     const { steps: validationSteps, result } = response;
     steps.push(...validationSteps);
     if (!result.success) {
       return { steps, result };
     }
 
     const { uri, file: fixedFile, mediaType, dimensions } = result;
     return {
       steps,
       result: {
         success: true,
         pendingUpload: {
           localID: getNextLocalUploadID(),
           serverID: null,
           messageID: null,
           failed: null,
           file: fixedFile,
           mediaType,
           dimensions,
           uri,
           loop: false,
           uriIsReal: false,
           progressPercent: 0,
           abort: null,
           steps,
           selectTime,
         },
       },
     };
   }
 
   uploadFiles(
     threadID: string,
     uploads: $ReadOnlyArray<PendingMultimediaUpload>,
   ) {
     return Promise.all(
       uploads.map(upload => this.uploadFile(threadID, upload)),
     );
   }
 
   async uploadFile(threadID: string, upload: PendingMultimediaUpload) {
     const { selectTime, localID } = upload;
     const steps = [...upload.steps];
     let userTime;
 
     const sendReport = (missionResult: MediaMissionResult) => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const latestUpload = this.state.pendingUploads[newThreadID][localID];
       invariant(
         latestUpload,
         `pendingUpload ${localID} for ${newThreadID} missing in sendReport`,
       );
       const { serverID, messageID } = latestUpload;
       const totalTime = Date.now() - selectTime;
       userTime = userTime ? userTime : totalTime;
       const mission = { steps, result: missionResult, totalTime, userTime };
       this.queueMediaMissionReports([
         {
           mediaMission: mission,
           uploadLocalID: localID,
           uploadServerID: serverID,
           messageLocalID: messageID,
         },
       ]);
     };
 
     let uploadResult, uploadExceptionMessage;
     const uploadStart = Date.now();
     try {
       uploadResult = await this.props.uploadMultimedia(
         upload.file,
         { ...upload.dimensions, loop: false },
         {
           onProgress: (percent: number) =>
             this.setProgress(threadID, localID, percent),
           abortHandler: (abort: () => void) =>
             this.handleAbortCallback(threadID, localID, abort),
         },
       );
     } catch (e) {
       uploadExceptionMessage = getMessageForException(e);
       this.handleUploadFailure(threadID, localID, e);
     }
     userTime = Date.now() - selectTime;
     steps.push({
       step: 'upload',
       success: !!uploadResult,
       exceptionMessage: uploadExceptionMessage,
       time: Date.now() - uploadStart,
       inputFilename: upload.file.name,
       outputMediaType: uploadResult && uploadResult.mediaType,
       outputURI: uploadResult && uploadResult.uri,
       outputDimensions: uploadResult && uploadResult.dimensions,
       outputLoop: uploadResult && uploadResult.loop,
     });
     if (!uploadResult) {
       sendReport({
         success: false,
         reason: 'http_upload_failed',
         exceptionMessage: uploadExceptionMessage,
       });
       return;
     }
     const result = uploadResult;
 
     const successThreadID = this.getRealizedOrPendingThreadID(threadID);
     const uploadAfterSuccess = this.state.pendingUploads[successThreadID][
       localID
     ];
     invariant(
       uploadAfterSuccess,
       `pendingUpload ${localID}/${result.id} for ${successThreadID} missing ` +
         `after upload`,
     );
     if (uploadAfterSuccess.messageID) {
       this.props.dispatch({
         type: updateMultimediaMessageMediaActionType,
         payload: {
           messageID: uploadAfterSuccess.messageID,
           currentMediaID: localID,
           mediaUpdate: {
             id: result.id,
           },
         },
       });
     }
 
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const uploads = prevState.pendingUploads[newThreadID];
       const currentUpload = uploads[localID];
       invariant(
         currentUpload,
         `pendingUpload ${localID}/${result.id} for ${newThreadID} ` +
           `missing while assigning serverID`,
       );
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: {
             ...uploads,
             [localID]: {
               ...currentUpload,
               serverID: result.id,
               abort: null,
             },
           },
         },
       };
     });
 
     const { steps: preloadSteps } = await preloadImage(result.uri);
     steps.push(...preloadSteps);
     sendReport({ success: true });
 
     const preloadThreadID = this.getRealizedOrPendingThreadID(threadID);
     const uploadAfterPreload = this.state.pendingUploads[preloadThreadID][
       localID
     ];
     invariant(
       uploadAfterPreload,
       `pendingUpload ${localID}/${result.id} for ${preloadThreadID} missing ` +
         `after preload`,
     );
     if (uploadAfterPreload.messageID) {
       const { mediaType, uri, dimensions, loop } = result;
       this.props.dispatch({
         type: updateMultimediaMessageMediaActionType,
         payload: {
           messageID: uploadAfterPreload.messageID,
           currentMediaID: uploadAfterPreload.serverID
             ? uploadAfterPreload.serverID
             : uploadAfterPreload.localID,
           mediaUpdate: { type: mediaType, uri, dimensions, loop },
         },
       });
     }
 
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const uploads = prevState.pendingUploads[newThreadID];
       const currentUpload = uploads[localID];
       invariant(
         currentUpload,
         `pendingUpload ${localID}/${result.id} for ${newThreadID} ` +
           `missing while assigning URI`,
       );
       const { messageID } = currentUpload;
       if (messageID && !messageID.startsWith(localIDPrefix)) {
         const newPendingUploads = _omit([localID])(uploads);
         return {
           pendingUploads: {
             ...prevState.pendingUploads,
             [newThreadID]: newPendingUploads,
           },
         };
       }
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: {
             ...uploads,
             [localID]: {
               ...currentUpload,
               uri: result.uri,
               mediaType: result.mediaType,
               dimensions: result.dimensions,
               uriIsReal: true,
               loop: result.loop,
             },
           },
         },
       };
     });
   }
 
   handleAbortCallback(
     threadID: string,
     localUploadID: string,
     abort: () => void,
   ) {
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const uploads = prevState.pendingUploads[newThreadID];
       const upload = uploads[localUploadID];
       if (!upload) {
         // The upload has been cancelled before we were even handed the
         // abort function. We should immediately abort.
         abort();
       }
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: {
             ...uploads,
             [localUploadID]: {
               ...upload,
               abort,
             },
           },
         },
       };
     });
   }
 
   handleUploadFailure(threadID: string, localUploadID: string, e: any) {
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const uploads = prevState.pendingUploads[newThreadID];
       const upload = uploads[localUploadID];
       if (!upload || !upload.abort || upload.serverID) {
         // The upload has been cancelled or completed before it failed
         return {};
       }
       const failed = e instanceof Error && e.message ? e.message : 'failed';
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: {
             ...uploads,
             [localUploadID]: {
               ...upload,
               failed,
               progressPercent: 0,
               abort: null,
             },
           },
         },
       };
     });
   }
 
   queueMediaMissionReports(
     partials: $ReadOnlyArray<{
       mediaMission: MediaMission,
       uploadLocalID?: ?string,
       uploadServerID?: ?string,
       messageLocalID?: ?string,
     }>,
   ) {
     const reports = partials.map(
       ({ mediaMission, uploadLocalID, uploadServerID, messageLocalID }) => ({
         type: reportTypes.MEDIA_MISSION,
         time: Date.now(),
         platformDetails: getConfig().platformDetails,
         mediaMission,
         uploadServerID,
         uploadLocalID,
         messageLocalID,
       }),
     );
     this.props.dispatch({ type: queueReportsActionType, payload: { reports } });
   }
 
   cancelPendingUpload(threadID: string, localUploadID: string) {
     let revokeURL, abortRequest;
     this.setState(
       prevState => {
         const newThreadID = this.getRealizedOrPendingThreadID(threadID);
         const currentPendingUploads = prevState.pendingUploads[newThreadID];
         if (!currentPendingUploads) {
           return {};
         }
         const pendingUpload = currentPendingUploads[localUploadID];
         if (!pendingUpload) {
           return {};
         }
         if (!pendingUpload.uriIsReal) {
           revokeURL = pendingUpload.uri;
         }
         if (pendingUpload.abort) {
           abortRequest = pendingUpload.abort;
         }
         if (pendingUpload.serverID) {
           this.props.deleteUpload(pendingUpload.serverID);
         }
         const newPendingUploads = _omit([localUploadID])(currentPendingUploads);
         return {
           pendingUploads: {
             ...prevState.pendingUploads,
             [newThreadID]: newPendingUploads,
           },
         };
       },
       () => {
         if (revokeURL) {
           URL.revokeObjectURL(revokeURL);
         }
         if (abortRequest) {
           abortRequest();
         }
       },
     );
   }
 
   async sendTextMessage(
     messageInfo: RawTextMessageInfo,
     threadInfo: ThreadInfo,
   ) {
     this.props.sendCallbacks.forEach(callback => callback());
 
     if (!threadIsPending(threadInfo.id)) {
       this.props.dispatchActionPromise(
         sendTextMessageActionTypes,
         this.sendTextMessageAction(messageInfo),
         undefined,
         messageInfo,
       );
       return;
     }
 
     this.props.dispatch({
       type: sendTextMessageActionTypes.started,
       payload: messageInfo,
     });
 
     let newThreadID = null;
     try {
       newThreadID = await this.startThreadCreation(threadInfo);
     } catch (e) {
       const copy = cloneError(e);
       copy.localID = messageInfo.localID;
       copy.threadID = messageInfo.threadID;
       this.props.dispatch({
         type: sendTextMessageActionTypes.failed,
         payload: copy,
         error: true,
       });
       return;
     } finally {
       this.pendingThreadCreations.delete(threadInfo.id);
     }
 
     const newMessageInfo = {
       ...messageInfo,
       threadID: newThreadID,
       time: Date.now(),
     };
     this.props.dispatchActionPromise(
       sendTextMessageActionTypes,
       this.sendTextMessageAction(newMessageInfo),
       undefined,
       newMessageInfo,
     );
   }
 
   async sendTextMessageAction(
     messageInfo: RawTextMessageInfo,
   ): Promise<SendMessagePayload> {
     try {
       const { localID } = messageInfo;
       invariant(
         localID !== null && localID !== undefined,
         'localID should be set',
       );
       const result = await this.props.sendTextMessage(
         messageInfo.threadID,
         localID,
         messageInfo.text,
       );
       return {
         localID,
         serverID: result.id,
         threadID: messageInfo.threadID,
         time: result.time,
         interface: result.interface,
       };
     } catch (e) {
       const copy = cloneError(e);
       copy.localID = messageInfo.localID;
       copy.threadID = messageInfo.threadID;
       throw copy;
     }
   }
 
   // Creates a MultimediaMessage from the unassigned pending uploads,
   // if there are any
   createMultimediaMessage(localID: number, threadInfo: ThreadInfo) {
     const localMessageID = `${localIDPrefix}${localID}`;
     this.startThreadCreation(threadInfo);
 
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadInfo.id);
       const currentPendingUploads = prevState.pendingUploads[newThreadID];
       if (!currentPendingUploads) {
         return {};
       }
       const newPendingUploads = {};
       let uploadAssigned = false;
       for (const localUploadID in currentPendingUploads) {
         const upload = currentPendingUploads[localUploadID];
         if (upload.messageID) {
           newPendingUploads[localUploadID] = upload;
         } else {
           const newUpload = {
             ...upload,
             messageID: localMessageID,
           };
           uploadAssigned = true;
           newPendingUploads[localUploadID] = newUpload;
         }
       }
       if (!uploadAssigned) {
         return {};
       }
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: newPendingUploads,
         },
       };
     });
   }
 
   setDraft(threadID: string, draft: string) {
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       return {
         drafts: {
           ...prevState.drafts,
           [newThreadID]: draft,
         },
       };
     });
   }
 
   setProgress(
     threadID: string,
     localUploadID: string,
     progressPercent: number,
   ) {
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadID);
       const pendingUploads = prevState.pendingUploads[newThreadID];
       if (!pendingUploads) {
         return {};
       }
       const pendingUpload = pendingUploads[localUploadID];
       if (!pendingUpload) {
         return {};
       }
       const newPendingUploads = {
         ...pendingUploads,
         [localUploadID]: {
           ...pendingUpload,
           progressPercent,
         },
       };
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: newPendingUploads,
         },
       };
     });
   }
 
   messageHasUploadFailure(
     pendingUploads: ?$ReadOnlyArray<PendingMultimediaUpload>,
   ) {
     if (!pendingUploads) {
       return false;
     }
     return pendingUploads.some(upload => upload.failed);
   }
 
   retryMultimediaMessage(
     localMessageID: string,
     threadInfo: ThreadInfo,
     pendingUploads: ?$ReadOnlyArray<PendingMultimediaUpload>,
   ) {
     const rawMessageInfo = this.getRawMultimediaMessageInfo(localMessageID);
     let newRawMessageInfo;
     // This conditional is for Flow
     if (rawMessageInfo.type === messageTypes.MULTIMEDIA) {
       newRawMessageInfo = ({
         ...rawMessageInfo,
         time: Date.now(),
       }: RawMediaMessageInfo);
     } else {
       newRawMessageInfo = ({
         ...rawMessageInfo,
         time: Date.now(),
       }: RawImagesMessageInfo);
     }
 
     this.startThreadCreation(threadInfo);
 
     const completed = InputStateContainer.completedMessageIDs(this.state);
     if (completed.has(localMessageID)) {
       this.sendMultimediaMessage(newRawMessageInfo);
       return;
     }
 
     if (!pendingUploads) {
       return;
     }
 
     // We're not actually starting the send here,
     // we just use this action to update the message's timestamp in Redux
     this.props.dispatch({
       type: sendMultimediaMessageActionTypes.started,
       payload: newRawMessageInfo,
     });
 
     const uploadIDsToRetry = new Set();
     const uploadsToRetry = [];
     for (const pendingUpload of pendingUploads) {
       const { serverID, messageID, localID, abort } = pendingUpload;
       if (serverID || messageID !== localMessageID) {
         continue;
       }
       if (abort) {
         abort();
       }
       uploadIDsToRetry.add(localID);
       uploadsToRetry.push(pendingUpload);
     }
 
     this.setState(prevState => {
       const newThreadID = this.getRealizedOrPendingThreadID(threadInfo.id);
       const prevPendingUploads = prevState.pendingUploads[newThreadID];
       if (!prevPendingUploads) {
         return {};
       }
       const newPendingUploads = {};
       let pendingUploadChanged = false;
       for (const localID in prevPendingUploads) {
         const pendingUpload = prevPendingUploads[localID];
         if (uploadIDsToRetry.has(localID) && !pendingUpload.serverID) {
           newPendingUploads[localID] = {
             ...pendingUpload,
             failed: null,
             progressPercent: 0,
             abort: null,
           };
           pendingUploadChanged = true;
         } else {
           newPendingUploads[localID] = pendingUpload;
         }
       }
       if (!pendingUploadChanged) {
         return {};
       }
       return {
         pendingUploads: {
           ...prevState.pendingUploads,
           [newThreadID]: newPendingUploads,
         },
       };
     });
 
     this.uploadFiles(threadInfo.id, uploadsToRetry);
   }
 
   addReply = (message: string) => {
     this.replyCallbacks.forEach(addReplyCallback => addReplyCallback(message));
   };
 
   addReplyListener = (callbackReply: (message: string) => void) => {
     this.replyCallbacks.push(callbackReply);
   };
 
   removeReplyListener = (callbackReply: (message: string) => void) => {
     this.replyCallbacks = this.replyCallbacks.filter(
       candidate => candidate !== callbackReply,
     );
   };
 
   render() {
     const { activeChatThreadID } = this.props;
     const inputState = activeChatThreadID
       ? this.inputStateSelector(activeChatThreadID)(this.state)
       : null;
     return (
       <InputStateContext.Provider value={inputState}>
         {this.props.children}
       </InputStateContext.Provider>
     );
   }
 }
 
 const ConnectedInputStateContainer: React.ComponentType<BaseProps> = React.memo<BaseProps>(
   function ConnectedInputStateContainer(props) {
     const exifRotate = useSelector(state => {
       const browser = detectBrowser(state.userAgent);
       return (
         !browser || (browser.name !== 'safari' && browser.name !== 'chrome')
       );
     });
     const activeChatThreadID = useSelector(
       state => state.navInfo.activeChatThreadID,
     );
     const viewerID = useSelector(
       state => state.currentUserInfo && state.currentUserInfo.id,
     );
     const messageStoreMessages = useSelector(
       state => state.messageStore.messages,
     );
-    const locallyUniqueToRealizedThreadIDs = useSelector(state =>
-      locallyUniqueToRealizedThreadIDsSelector(state.threadStore.threadInfos),
+    const pendingToRealizedThreadIDs = useSelector(state =>
+      pendingToRealizedThreadIDsSelector(state.threadStore.threadInfos),
     );
     const calendarQuery = useSelector(nonThreadCalendarQuery);
     const callUploadMultimedia = useServerCall(uploadMultimedia);
     const callDeleteUpload = useServerCall(deleteUpload);
     const callSendMultimediaMessage = useServerCall(sendMultimediaMessage);
     const callSendTextMessage = useServerCall(sendTextMessage);
     const callNewThread = useServerCall(newThread);
     const dispatch = useDispatch();
     const dispatchActionPromise = useDispatchActionPromise();
     const modalContext = useModalContext();
 
     const [sendCallbacks, setSendCallbacks] = React.useState<
       $ReadOnlyArray<() => mixed>,
     >([]);
     const registerSendCallback = React.useCallback((callback: () => mixed) => {
       setSendCallbacks(prevCallbacks => [...prevCallbacks, callback]);
     }, []);
     const unregisterSendCallback = React.useCallback(
       (callback: () => mixed) => {
         setSendCallbacks(prevCallbacks =>
           prevCallbacks.filter(candidate => candidate !== callback),
         );
       },
       [],
     );
 
     return (
       <InputStateContainer
         {...props}
         activeChatThreadID={activeChatThreadID}
         viewerID={viewerID}
         messageStoreMessages={messageStoreMessages}
         exifRotate={exifRotate}
-        locallyUniqueRealizedThreadIDs={locallyUniqueToRealizedThreadIDs}
+        pendingRealizedThreadIDs={pendingToRealizedThreadIDs}
         calendarQuery={calendarQuery}
         uploadMultimedia={callUploadMultimedia}
         deleteUpload={callDeleteUpload}
         sendMultimediaMessage={callSendMultimediaMessage}
         sendTextMessage={callSendTextMessage}
         newThread={callNewThread}
         dispatch={dispatch}
         dispatchActionPromise={dispatchActionPromise}
         pushModal={modalContext.pushModal}
         sendCallbacks={sendCallbacks}
         registerSendCallback={registerSendCallback}
         unregisterSendCallback={unregisterSendCallback}
       />
     );
   },
 );
 
 export default ConnectedInputStateContainer;
diff --git a/web/redux/nav-reducer.js b/web/redux/nav-reducer.js
index df88150cc..80fd83cba 100644
--- a/web/redux/nav-reducer.js
+++ b/web/redux/nav-reducer.js
@@ -1,45 +1,43 @@
 // @flow
 
-import { locallyUniqueToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
+import { pendingToRealizedThreadIDsSelector } from 'lib/selectors/thread-selectors';
 import { threadIsPending } from 'lib/shared/thread-utils';
 import type { RawThreadInfo } from 'lib/types/thread-types';
 
 import type { Action } from '../redux/redux-setup';
 import { type NavInfo, updateNavInfoActionType } from '../types/nav-types';
 
 export default function reduceNavInfo(
   oldState: NavInfo,
   action: Action,
   newThreadInfos: { +[id: string]: RawThreadInfo },
 ): NavInfo {
   let state = oldState;
   if (action.type === updateNavInfoActionType) {
     state = {
       ...state,
       ...action.payload,
     };
   }
 
   const { activeChatThreadID } = state;
   if (activeChatThreadID) {
-    const locallyUniqueToRealizedThreadIDs = locallyUniqueToRealizedThreadIDsSelector(
+    const pendingToRealizedThreadIDs = pendingToRealizedThreadIDsSelector(
       newThreadInfos,
     );
-    const realizedThreadID = locallyUniqueToRealizedThreadIDs.get(
-      activeChatThreadID,
-    );
+    const realizedThreadID = pendingToRealizedThreadIDs.get(activeChatThreadID);
     if (realizedThreadID) {
       state = {
         ...state,
         activeChatThreadID: realizedThreadID,
       };
     }
   }
 
   if (state.pendingThread && !threadIsPending(state.activeChatThreadID)) {
     const { pendingThread, ...stateWithoutPendingThread } = state;
     state = stateWithoutPendingThread;
   }
 
   return state;
 }