diff --git a/keyserver/src/deleters/thread-deleters.js b/keyserver/src/deleters/thread-deleters.js
index 6d5966b5e..6e52a6c4b 100644
--- a/keyserver/src/deleters/thread-deleters.js
+++ b/keyserver/src/deleters/thread-deleters.js
@@ -1,140 +1,140 @@
 // @flow
 
 import { permissionLookup } from 'lib/permissions/thread-permissions.js';
 import { threadPermissions } from 'lib/types/thread-permission-types.js';
 import {
   type ThreadDeletionRequest,
   type LeaveThreadResult,
 } from 'lib/types/thread-types.js';
 import { updateTypes } from 'lib/types/update-types-enum.js';
 import { ServerError } from 'lib/utils/errors.js';
 
 import { createUpdates } from '../creators/update-creator.js';
 import { dbQuery, SQL } from '../database/database.js';
 import {
   fetchServerThreadInfos,
   fetchContainedThreadIDs,
 } from '../fetchers/thread-fetchers.js';
 import { fetchThreadPermissionsBlob } from '../fetchers/thread-permission-fetchers.js';
 import { fetchUpdateInfoForThreadDeletion } from '../fetchers/update-fetchers.js';
 import { rescindPushNotifs } from '../push/rescind.js';
 import type { Viewer } from '../session/viewer.js';
 
 async function deleteThread(
   viewer: Viewer,
   threadDeletionRequest: ThreadDeletionRequest,
 ): Promise<LeaveThreadResult> {
   if (!viewer.loggedIn) {
     throw new ServerError('not_logged_in');
   }
   const { threadID } = threadDeletionRequest;
 
   const permissionsBlob = await fetchThreadPermissionsBlob(viewer, threadID);
 
   if (!permissionsBlob) {
     // This should only occur if the first request goes through but the client
     // never receives the response
     const { updateInfos } = await fetchUpdateInfoForThreadDeletion(
       viewer,
       threadID,
     );
     return { updatesResult: { newUpdates: updateInfos } };
   }
 
   const hasPermission = permissionLookup(
     permissionsBlob,
     threadPermissions.DELETE_THREAD,
   );
   if (!hasPermission) {
     throw new ServerError('invalid_credentials');
   }
 
   // TODO: handle descendant thread permission update correctly.
   //       thread-permission-updaters should be used for descendant threads.
   const threadIDs = await fetchContainedThreadIDs(threadID);
 
   const [{ threadInfos: serverThreadInfos }] = await Promise.all([
-    fetchServerThreadInfos({ threadIDs: new Set(threadID) }),
+    fetchServerThreadInfos({ threadIDs: new Set(threadIDs) }),
     rescindPushNotifs(
       SQL`n.thread IN (${threadIDs})`,
       SQL`IF(m.thread IN (${threadIDs}), NULL, m.thread)`,
     ),
   ]);
 
   const query = SQL`
     DELETE t, ic, d, id, e, ie, re, ire, mm, r, ir, ms, im, up, iu, f, n, ino
     FROM threads t
     LEFT JOIN ids ic ON ic.id = t.id
     LEFT JOIN days d ON d.thread = t.id
     LEFT JOIN ids id ON id.id = d.id
     LEFT JOIN entries e ON e.day = d.id
     LEFT JOIN ids ie ON ie.id = e.id
     LEFT JOIN revisions re ON re.entry = e.id
     LEFT JOIN ids ire ON ire.id = re.id
     LEFT JOIN memberships mm ON mm.thread = t.id
     LEFT JOIN roles r ON r.thread = t.id
     LEFT JOIN ids ir ON ir.id = r.id
     LEFT JOIN messages ms ON ms.thread = t.id
     LEFT JOIN ids im ON im.id = ms.id
     LEFT JOIN uploads up ON (up.container = ms.id OR up.container = t.id)
     LEFT JOIN ids iu ON iu.id = up.id
     LEFT JOIN focused f ON f.thread = t.id
     LEFT JOIN notifications n ON n.thread = t.id
     LEFT JOIN ids ino ON ino.id = n.id
     WHERE t.id IN (${threadIDs})
   `;
 
   const time = Date.now();
   const updateDatas = [];
   for (const containedThreadID of threadIDs) {
     for (const memberInfo of serverThreadInfos[containedThreadID].members) {
       updateDatas.push({
         type: updateTypes.DELETE_THREAD,
         userID: memberInfo.id,
         time,
         threadID: containedThreadID,
       });
     }
   }
 
   const [{ viewerUpdates }] = await Promise.all([
     createUpdates(updateDatas, { viewer, updatesForCurrentSession: 'return' }),
     dbQuery(query),
   ]);
 
   return { updatesResult: { newUpdates: viewerUpdates } };
 }
 
 async function deleteInaccessibleThreads(): Promise<void> {
   // A thread is considered "inaccessible" if it has no membership rows. Note
   // that membership rows exist whenever a user can see a thread, even if they
   // are not technically a member (in which case role=0). For now, we're also
   // excluding threads with children, since to properly delete those we would
   // need to update their parent_thread_id, and possibly change their type.
   await dbQuery(SQL`
     DELETE t, i, m2, d, id, e, ie, re, ire, r, ir, ms, im, up, iu, f, n, ino
     FROM threads t
     LEFT JOIN ids i ON i.id = t.id
     LEFT JOIN memberships m1 ON m1.thread = t.id AND m1.role > -1
     LEFT JOIN threads c ON c.parent_thread_id = t.id
     LEFT JOIN memberships m2 ON m2.thread = t.id
     LEFT JOIN days d ON d.thread = t.id
     LEFT JOIN ids id ON id.id = d.id
     LEFT JOIN entries e ON e.day = d.id
     LEFT JOIN ids ie ON ie.id = e.id
     LEFT JOIN revisions re ON re.entry = e.id
     LEFT JOIN ids ire ON ire.id = re.id
     LEFT JOIN roles r ON r.thread = t.id
     LEFT JOIN ids ir ON ir.id = r.id
     LEFT JOIN messages ms ON ms.thread = t.id
     LEFT JOIN ids im ON im.id = ms.id
     LEFT JOIN uploads up ON (up.container = ms.id OR up.container = t.id)
     LEFT JOIN ids iu ON iu.id = up.id
     LEFT JOIN focused f ON f.thread = t.id
     LEFT JOIN notifications n ON n.thread = t.id
     LEFT JOIN ids ino ON ino.id = n.id
     WHERE m1.thread IS NULL AND c.id IS NULL
   `);
 }
 
 export { deleteThread, deleteInaccessibleThreads };