diff --git a/server/src/fetchers/message-fetchers.js b/server/src/fetchers/message-fetchers.js
index f45c91722..852bf05e4 100644
--- a/server/src/fetchers/message-fetchers.js
+++ b/server/src/fetchers/message-fetchers.js
@@ -1,640 +1,705 @@
 // @flow
 
 import invariant from 'invariant';
 
 import {
   sortMessageInfoList,
   shimUnsupportedRawMessageInfos,
 } from 'lib/shared/message-utils';
 import { messageSpecs } from 'lib/shared/messages/message-specs';
 import { notifCollapseKeyForRawMessageInfo } from 'lib/shared/notif-utils';
 import { hasMinCodeVersion } from 'lib/shared/version-utils';
 import {
   type RawMessageInfo,
   type RawComposableMessageInfo,
   type RawRobotextMessageInfo,
   messageTypes,
   type MessageType,
   assertMessageType,
   type MessageSelectionCriteria,
   type MessageTruncationStatus,
   messageTruncationStatus,
   type FetchMessageInfosResult,
   defaultMaxMessageAge,
 } from 'lib/types/message-types';
 import { threadPermissions } from 'lib/types/thread-types';
 import { ServerError } from 'lib/utils/errors';
 
 import {
   dbQuery,
   SQL,
   mergeOrConditions,
   mergeAndConditions,
 } from '../database/database';
 import type { PushInfo } from '../push/send';
 import type { Viewer } from '../session/viewer';
 import { creationString, localIDFromCreationString } from '../utils/idempotent';
 import { mediaFromRow } from './upload-fetchers';
 
 export type CollapsableNotifInfo = {
   collapseKey: ?string,
   existingMessageInfos: RawMessageInfo[],
   newMessageInfos: RawMessageInfo[],
 };
 export type FetchCollapsableNotifsResult = {
   [userID: string]: CollapsableNotifInfo[],
 };
 
 const visibleExtractString = `$.${threadPermissions.VISIBLE}.value`;
 
 // This function doesn't filter RawMessageInfos based on what messageTypes the
 // client supports, since each user can have multiple clients. The caller must
 // handle this filtering.
 async function fetchCollapsableNotifs(
   pushInfo: PushInfo,
 ): Promise<FetchCollapsableNotifsResult> {
   // First, we need to fetch any notifications that should be collapsed
   const usersToCollapseKeysToInfo = {};
   const usersToCollapsableNotifInfo = {};
   for (const userID in pushInfo) {
     usersToCollapseKeysToInfo[userID] = {};
     usersToCollapsableNotifInfo[userID] = [];
     for (const rawMessageInfo of pushInfo[userID].messageInfos) {
       const collapseKey = notifCollapseKeyForRawMessageInfo(rawMessageInfo);
       if (!collapseKey) {
         const collapsableNotifInfo = {
           collapseKey,
           existingMessageInfos: [],
           newMessageInfos: [rawMessageInfo],
         };
         usersToCollapsableNotifInfo[userID].push(collapsableNotifInfo);
         continue;
       }
       if (!usersToCollapseKeysToInfo[userID][collapseKey]) {
         usersToCollapseKeysToInfo[userID][collapseKey] = {
           collapseKey,
           existingMessageInfos: [],
           newMessageInfos: [],
         };
       }
       usersToCollapseKeysToInfo[userID][collapseKey].newMessageInfos.push(
         rawMessageInfo,
       );
     }
   }
 
   const sqlTuples = [];
   for (const userID in usersToCollapseKeysToInfo) {
     const collapseKeysToInfo = usersToCollapseKeysToInfo[userID];
     for (const collapseKey in collapseKeysToInfo) {
       sqlTuples.push(
         SQL`(n.user = ${userID} AND n.collapse_key = ${collapseKey})`,
       );
     }
   }
 
   if (sqlTuples.length === 0) {
     return usersToCollapsableNotifInfo;
   }
 
   const collapseQuery = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type,
       m.user AS creatorID, stm.permissions AS subthread_permissions, n.user,
       n.collapse_key, up.id AS uploadID, up.type AS uploadType,
       up.secret AS uploadSecret, up.extra AS uploadExtra
     FROM notifications n
     LEFT JOIN messages m ON m.id = n.message
     LEFT JOIN uploads up
       ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
         AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = n.user
     LEFT JOIN memberships stm
       ON m.type = ${messageTypes.CREATE_SUB_THREAD}
         AND stm.thread = m.content AND stm.user = n.user
     WHERE n.rescinded = 0 AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
   collapseQuery.append(mergeOrConditions(sqlTuples));
   collapseQuery.append(SQL`ORDER BY m.time DESC`);
   const [collapseResult] = await dbQuery(collapseQuery);
 
   const rowsByUser = new Map();
   for (const row of collapseResult) {
     const user = row.user.toString();
     const currentRowsForUser = rowsByUser.get(user);
     if (currentRowsForUser) {
       currentRowsForUser.push(row);
     } else {
       rowsByUser.set(user, [row]);
     }
   }
 
   const derivedMessages = await fetchDerivedMessages(collapseResult);
   for (const userRows of rowsByUser.values()) {
     const messages = parseMessageSQLResult(userRows, derivedMessages);
     for (const message of messages) {
       const { rawMessageInfo, rows } = message;
       const [row] = rows;
       const info = usersToCollapseKeysToInfo[row.user][row.collapse_key];
       info.existingMessageInfos.push(rawMessageInfo);
     }
   }
 
   for (const userID in usersToCollapseKeysToInfo) {
     const collapseKeysToInfo = usersToCollapseKeysToInfo[userID];
     for (const collapseKey in collapseKeysToInfo) {
       const info = collapseKeysToInfo[collapseKey];
       usersToCollapsableNotifInfo[userID].push({
         collapseKey: info.collapseKey,
         existingMessageInfos: sortMessageInfoList(info.existingMessageInfos),
         newMessageInfos: sortMessageInfoList(info.newMessageInfos),
       });
     }
   }
 
   return usersToCollapsableNotifInfo;
 }
 
 type MessageSQLResult = $ReadOnlyArray<{
   rawMessageInfo: RawMessageInfo,
   rows: $ReadOnlyArray<Object>,
 }>;
 function parseMessageSQLResult(
   rows: $ReadOnlyArray<Object>,
   derivedMessages: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
   viewer?: Viewer,
 ): MessageSQLResult {
   const rowsByID = new Map();
   for (const row of rows) {
     const id = row.id.toString();
     const currentRowsForID = rowsByID.get(id);
     if (currentRowsForID) {
       currentRowsForID.push(row);
     } else {
       rowsByID.set(id, [row]);
     }
   }
 
   const messages = [];
   for (const messageRows of rowsByID.values()) {
     const rawMessageInfo = rawMessageInfoFromRows(
       messageRows,
       viewer,
       derivedMessages,
     );
     if (rawMessageInfo) {
       messages.push({ rawMessageInfo, rows: messageRows });
     }
   }
 
   return messages;
 }
 
 function assertSingleRow(rows: $ReadOnlyArray<Object>): Object {
   if (rows.length === 0) {
     throw new Error('expected single row, but none present!');
   } else if (rows.length !== 1) {
     const messageIDs = rows.map(row => row.id.toString());
     console.warn(
       `expected single row, but there are multiple! ${messageIDs.join(', ')}`,
     );
   }
   return rows[0];
 }
 
 function mostRecentRowType(rows: $ReadOnlyArray<Object>): MessageType {
   if (rows.length === 0) {
     throw new Error('expected row, but none present!');
   }
   return assertMessageType(rows[0].type);
 }
 
 function rawMessageInfoFromRows(
   rows: $ReadOnlyArray<Object>,
   viewer?: Viewer,
   derivedMessages: $ReadOnlyMap<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >,
 ): ?RawMessageInfo {
   const type = mostRecentRowType(rows);
   const messageSpec = messageSpecs[type];
 
   if (type === messageTypes.IMAGES || type === messageTypes.MULTIMEDIA) {
     const media = rows.filter(row => row.uploadID).map(mediaFromRow);
     const [row] = rows;
     const localID = localIDFromCreationString(viewer, row.creation);
     invariant(
       messageSpec.rawMessageInfoFromServerDBRow,
       `multimedia message spec should have rawMessageInfoFromServerDBRow`,
     );
     return messageSpec.rawMessageInfoFromServerDBRow(row, {
       media,
       derivedMessages,
       localID,
     });
   }
 
   const row = assertSingleRow(rows);
   const localID = localIDFromCreationString(viewer, row.creation);
   invariant(
     messageSpec.rawMessageInfoFromServerDBRow,
     `message spec ${type} should have rawMessageInfoFromServerDBRow`,
   );
   return messageSpec.rawMessageInfoFromServerDBRow(row, {
     derivedMessages,
     localID,
   });
 }
 
 async function fetchMessageInfos(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
   numberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
   const selectionClause = messageSelectionCriteriaToSQLClause(viewer, criteria);
   const truncationStatuses = {};
 
   const viewerID = viewer.id;
   const query = SQL`
     SELECT * FROM (
       SELECT x.id, x.content, x.time, x.type, x.user AS creatorID,
         x.creation, x.subthread_permissions, x.uploadID, x.uploadType,
         x.uploadSecret, x.uploadExtra,
         @num := if(
           @thread = x.thread,
           if(@message = x.id, @num, @num + 1),
           1
         ) AS number,
         @message := x.id AS messageID,
         @thread := x.thread AS threadID
       FROM (SELECT @num := 0, @thread := '', @message := '') init
       JOIN (
         SELECT m.id, m.thread, m.user, m.content, m.time, m.type,
           m.creation, stm.permissions AS subthread_permissions,
           up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
           up.extra AS uploadExtra
         FROM messages m
         LEFT JOIN uploads up
           ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
             AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
         LEFT JOIN memberships mm
           ON mm.thread = m.thread AND mm.user = ${viewerID}
         LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
           AND stm.thread = m.content AND stm.user = ${viewerID}
         WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
   query.append(selectionClause);
   query.append(SQL`
         ORDER BY m.thread, m.time DESC
       ) x
     ) y
     WHERE y.number <= ${numberPerThread}
   `);
   const [result] = await dbQuery(query);
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   const messages = parseMessageSQLResult(result, derivedMessages, viewer);
 
   const rawMessageInfos = [];
   const threadToMessageCount = new Map();
   for (const message of messages) {
     const { rawMessageInfo } = message;
     rawMessageInfos.push(rawMessageInfo);
     const { threadID } = rawMessageInfo;
     const currentCountValue = threadToMessageCount.get(threadID);
     const currentCount = currentCountValue ? currentCountValue : 0;
     threadToMessageCount.set(threadID, currentCount + 1);
   }
 
   for (const [threadID, messageCount] of threadToMessageCount) {
-    // If there are fewer messages returned than the max for a given thread,
-    // then our result set includes all messages in the query range for that
-    // thread
-    truncationStatuses[threadID] =
-      messageCount < numberPerThread
-        ? messageTruncationStatus.EXHAUSTIVE
-        : messageTruncationStatus.TRUNCATED;
+    if (messageCount >= numberPerThread) {
+      // If we matched the exact amount we limited to, we're probably truncating
+      // our result set. By setting TRUNCATED here, we tell the client that the
+      // result set might not be continguous with what's already in their
+      // MessageStore. Note that we may unset TRUNCATED below. More details
+      // about TRUNCATED can be found in lib/types/message-types.js
+      truncationStatuses[threadID] = messageTruncationStatus.TRUNCATED;
+      continue;
+    }
+    const hasTimeFilter = messageSelectionCriteriaHasTimeFilterForThread(
+      viewer,
+      criteria,
+      threadID,
+    );
+    if (!hasTimeFilter) {
+      // If there is no time filter for a given thread, and there are fewer
+      // messages returned than the max we queried for a given thread, we can
+      // conclude that our result set includes all messages for that thread
+      truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
+    }
   }
 
   for (const rawMessageInfo of rawMessageInfos) {
     if (messageSpecs[rawMessageInfo.type].startsThread) {
       truncationStatuses[rawMessageInfo.threadID] =
         messageTruncationStatus.EXHAUSTIVE;
     }
   }
 
   for (const threadID in criteria.threadCursors) {
     const truncationStatus = truncationStatuses[threadID];
     if (truncationStatus === null || truncationStatus === undefined) {
-      // If nothing was returned for a thread that was explicitly queried for,
-      // then our result set includes all messages in the query range for that
-      // thread
-      truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
+      const hasTimeFilter = messageSelectionCriteriaHasTimeFilterForThread(
+        viewer,
+        criteria,
+        threadID,
+      );
+      if (!hasTimeFilter) {
+        // If there is no time filter for a given thread, and zero messages were
+        // returned, we can conclude that this thread has zero messages. This is
+        // a case of database corruption that should not be possible, but likely
+        // we have some threads like this on prod (either due to some transient
+        // issues or due to old buggy code)
+        truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
+      } else {
+        // If this thread was explicitly queried for, and we got no results, but
+        // we can't conclude that it's EXHAUSTIVE, then we'll set to UNCHANGED.
+        truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
+      }
     } else if (truncationStatus === messageTruncationStatus.TRUNCATED) {
       // If a cursor was specified for a given thread, then the result is
       // guaranteed to be contiguous with what the client has, and as such the
       // result should never be TRUNCATED
       truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
     }
   }
 
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
 
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
+// This function is set up to track the behavior of
+// messageSelectionCriteriaToSQLClause, and any changes there must be kept in
+// sync here.
+function messageSelectionCriteriaHasTimeFilterForThread(
+  viewer: Viewer,
+  criteria: MessageSelectionCriteria,
+  threadID: string,
+) {
+  // If newerThan is set, then a global time filter is applied, no matter what
+  if (criteria.newerThan) {
+    return true;
+  }
+
+  // If newerThan isn't set, and threadID is present in threadCursors, then
+  // there definitely is no time filter for this thread, since:
+  // (1) There is no global time filter because newerThan isn't set and
+  //     threadCursors is
+  // (2) The threadCursors clause will not be time-filtered, even if
+  //     joinedThreads is (and those clauses are OR'd)
+  if (criteria.threadCursors && threadID in criteria.threadCursors) {
+    return false;
+  }
+
+  // If the above two conditions don't match, then we have to ask if there is a
+  // default global time filter applied. If we're not applying a default global
+  // time filter, then there's no time filter here
+  const shouldApplyTimeFilter = hasMinCodeVersion(viewer.platformDetails, 130);
+  if (!shouldApplyTimeFilter) {
+    return false;
+  }
+
+  // If threadCursors is set, we never apply a global time filter
+  return !criteria.threadCursors;
+}
+
+// The function defined above (messageSelectionCriteriaHasTimeFilterForThread)
+// is set up to track the behavior of this function
+// (messageSelectionCriteriaToSQLClause), and any changes here must be kept in
+// sync there.
 function messageSelectionCriteriaToSQLClause(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
 ) {
   const minMessageTime = Date.now() - defaultMaxMessageAge;
   const shouldApplyTimeFilter = hasMinCodeVersion(viewer.platformDetails, 130);
 
   let globalTimeFilter;
   if (criteria.newerThan) {
     globalTimeFilter = SQL`m.time > ${criteria.newerThan}`;
   } else if (!criteria.threadCursors && shouldApplyTimeFilter) {
     globalTimeFilter = SQL`m.time > ${minMessageTime}`;
   }
 
   const threadConditions = [];
   if (
     criteria.joinedThreads === true &&
     shouldApplyTimeFilter &&
     !globalTimeFilter
   ) {
     threadConditions.push(SQL`(mm.role > 0 AND m.time > ${minMessageTime})`);
   } else if (criteria.joinedThreads === true) {
     threadConditions.push(SQL`mm.role > 0`);
   }
   if (criteria.threadCursors) {
     for (const threadID in criteria.threadCursors) {
       const cursor = criteria.threadCursors[threadID];
       if (cursor) {
         threadConditions.push(
           SQL`(m.thread = ${threadID} AND m.id < ${cursor})`,
         );
       } else {
         threadConditions.push(SQL`m.thread = ${threadID}`);
       }
     }
   }
   if (threadConditions.length === 0) {
     throw new ServerError('internal_error');
   }
   const threadClause = mergeOrConditions(threadConditions);
 
   const conditions = [globalTimeFilter, threadClause].filter(Boolean);
   return mergeAndConditions(conditions);
 }
 
 function messageSelectionCriteriaToInitialTruncationStatuses(
   criteria: MessageSelectionCriteria,
   defaultTruncationStatus: MessageTruncationStatus,
 ) {
   const truncationStatuses = {};
   if (criteria.threadCursors) {
     for (const threadID in criteria.threadCursors) {
       truncationStatuses[threadID] = defaultTruncationStatus;
     }
   }
   return truncationStatuses;
 }
 
 async function fetchMessageInfosSince(
   viewer: Viewer,
   criteria: MessageSelectionCriteria,
   maxNumberPerThread: number,
 ): Promise<FetchMessageInfosResult> {
   const selectionClause = messageSelectionCriteriaToSQLClause(viewer, criteria);
   const truncationStatuses = messageSelectionCriteriaToInitialTruncationStatuses(
     criteria,
     messageTruncationStatus.UNCHANGED,
   );
 
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type,
       m.creation, m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up
       ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
         AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = ${viewerID}
     WHERE JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE AND
   `;
   query.append(selectionClause);
   query.append(SQL`
     ORDER BY m.thread, m.time DESC
   `);
   const [result] = await dbQuery(query);
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   const messages = parseMessageSQLResult(result, derivedMessages, viewer);
 
   const rawMessageInfos = [];
   let currentThreadID = null;
   let numMessagesForCurrentThreadID = 0;
   for (const message of messages) {
     const { rawMessageInfo } = message;
     const { threadID } = rawMessageInfo;
     if (threadID !== currentThreadID) {
       currentThreadID = threadID;
       numMessagesForCurrentThreadID = 1;
       truncationStatuses[threadID] = messageTruncationStatus.UNCHANGED;
     } else {
       numMessagesForCurrentThreadID++;
     }
     if (numMessagesForCurrentThreadID <= maxNumberPerThread) {
       if (messageSpecs[rawMessageInfo.type].startsThread) {
         truncationStatuses[threadID] = messageTruncationStatus.EXHAUSTIVE;
       }
       rawMessageInfos.push(rawMessageInfo);
     } else if (numMessagesForCurrentThreadID === maxNumberPerThread + 1) {
       truncationStatuses[threadID] = messageTruncationStatus.TRUNCATED;
     }
   }
 
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
 
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
 function getMessageFetchResultFromRedisMessages(
   viewer: Viewer,
   rawMessageInfos: $ReadOnlyArray<RawMessageInfo>,
 ): FetchMessageInfosResult {
   const truncationStatuses = {};
   for (const rawMessageInfo of rawMessageInfos) {
     truncationStatuses[rawMessageInfo.threadID] =
       messageTruncationStatus.UNCHANGED;
   }
   const shimmedRawMessageInfos = shimUnsupportedRawMessageInfos(
     rawMessageInfos,
     viewer.platformDetails,
   );
   return {
     rawMessageInfos: shimmedRawMessageInfos,
     truncationStatuses,
   };
 }
 
 async function fetchMessageInfoForLocalID(
   viewer: Viewer,
   localID: ?string,
 ): Promise<?RawMessageInfo> {
   if (!localID || !viewer.hasSessionInfo) {
     return null;
   }
   const creation = creationString(viewer, localID);
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation,
       m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret,
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up
       ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
         AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = ${viewerID}
     WHERE m.user = ${viewerID} AND m.creation = ${creation} AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE
   `;
 
   const [result] = await dbQuery(query);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 const entryIDExtractString = '$.entryID';
 async function fetchMessageInfoForEntryAction(
   viewer: Viewer,
   messageType: MessageType,
   entryID: string,
   threadID: string,
 ): Promise<?RawMessageInfo> {
   const viewerID = viewer.id;
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation,
       m.user AS creatorID, up.id AS uploadID, up.type AS uploadType,
       up.secret AS uploadSecret, up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up
       ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
         AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
     LEFT JOIN memberships mm ON mm.thread = m.thread AND mm.user = ${viewerID}
     WHERE m.user = ${viewerID} AND m.thread = ${threadID} AND
       m.type = ${messageType} AND
       JSON_EXTRACT(m.content, ${entryIDExtractString}) = ${entryID} AND
       JSON_EXTRACT(mm.permissions, ${visibleExtractString}) IS TRUE
   `;
 
   const [result] = await dbQuery(query);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 async function fetchMessageRowsByIDs(messageIDs: $ReadOnlyArray<string>) {
   const query = SQL`
     SELECT m.id, m.thread AS threadID, m.content, m.time, m.type, m.creation, 
       m.user AS creatorID, stm.permissions AS subthread_permissions,
       up.id AS uploadID, up.type AS uploadType, up.secret AS uploadSecret, 
       up.extra AS uploadExtra
     FROM messages m
     LEFT JOIN uploads up
       ON m.type IN (${[messageTypes.IMAGES, messageTypes.MULTIMEDIA]})
         AND JSON_CONTAINS(m.content, CAST(up.id as JSON), '$')
     LEFT JOIN memberships stm ON m.type = ${messageTypes.CREATE_SUB_THREAD}
       AND stm.thread = m.content AND stm.user = m.user
     WHERE m.id IN (${messageIDs})
   `;
   const [result] = await dbQuery(query);
   return result;
 }
 
 async function fetchDerivedMessages(
   rows: $ReadOnlyArray<Object>,
   viewer?: Viewer,
 ): Promise<
   $ReadOnlyMap<string, RawComposableMessageInfo | RawRobotextMessageInfo>,
 > {
   const requiredIDs = new Set<string>();
   for (const row of rows) {
     if (row.type === messageTypes.SIDEBAR_SOURCE) {
       const content = JSON.parse(row.content);
       requiredIDs.add(content.sourceMessageID);
     }
   }
 
   const messagesByID = new Map<
     string,
     RawComposableMessageInfo | RawRobotextMessageInfo,
   >();
   if (requiredIDs.size === 0) {
     return messagesByID;
   }
 
   const result = await fetchMessageRowsByIDs([...requiredIDs]);
   const messages = parseMessageSQLResult(result, new Map(), viewer);
 
   for (const message of messages) {
     const { rawMessageInfo } = message;
     if (rawMessageInfo.id) {
       invariant(
         rawMessageInfo.type !== messageTypes.SIDEBAR_SOURCE,
         'SIDEBAR_SOURCE should not point to a SIDEBAR_SOURCE',
       );
       messagesByID.set(rawMessageInfo.id, rawMessageInfo);
     }
   }
   return messagesByID;
 }
 
 async function fetchMessageInfoByID(
   viewer?: Viewer,
   messageID: string,
 ): Promise<?RawMessageInfo> {
   const result = await fetchMessageRowsByIDs([messageID]);
   if (result.length === 0) {
     return null;
   }
   const derivedMessages = await fetchDerivedMessages(result, viewer);
   return rawMessageInfoFromRows(result, viewer, derivedMessages);
 }
 
 export {
   fetchCollapsableNotifs,
   fetchMessageInfos,
   fetchMessageInfosSince,
   getMessageFetchResultFromRedisMessages,
   fetchMessageInfoForLocalID,
   fetchMessageInfoForEntryAction,
   fetchMessageInfoByID,
 };