Preserve thread numbering in placeholders (#11616)

src/lib/api/feed-manip.test.ts

@@ -0,0 +1,54 @@
+import {type app} from '#/lexicons'
+import {createFeedViewPostsSlices} from './feed-manip'
+
+jest.mock('./feed/home', () => ({
+  FALLBACK_MARKER_POST: {post: {uri: 'at://did:plc:test/app.bsky.feed.post/1'}},
+}))
+
+const author = {
+  $type: 'app.bsky.actor.defs#profileViewBasic',
+  did: 'did:plc:alice',
+  handle: 'alice.test',
+} as app.bsky.actor.defs.ProfileViewBasic
+
+function post(id: string) {
+  return {
+    $type: 'app.bsky.feed.defs#postView',
+    uri: `at://did:plc:alice/app.bsky.feed.post/${id}`,
+    cid: id,
+    author,
+    record: {
+      $type: 'app.bsky.feed.post',
+      text: id,
+      createdAt: '2026-08-31T00:00:00.000Z',
+    },
+    indexedAt: '2026-08-31T00:00:00.000Z',
+  } as app.bsky.feed.defs.PostView
+}
+
+describe('createFeedViewPostsSlices', () => {
+  it('preserves selected numbering and infers hydrated parent and root numbering', () => {
+    const root = post('root')
+    const parent = post('parent')
+    const selected = post('selected')
+    const feedPost = {
+      post: selected,
+      reply: {root, parent},
+      opThreadPostIndex: 3,
+      opThreadPostCount: 4,
+    } as app.bsky.feed.defs.FeedViewPost & {
+      opThreadPostIndex: number
+      opThreadPostCount: number
+    }
+
+    const [slice] = createFeedViewPostsSlices([feedPost])
+
+    expect(
+      slice.items.map(item => [item.post.uri, item.postNumbering]),
+    ).toEqual([
+      [root.uri, {opThreadPostIndex: 1, opThreadPostCount: 4}],
+      [parent.uri, {opThreadPostIndex: 2, opThreadPostCount: 4}],
+      [selected.uri, {opThreadPostIndex: 3, opThreadPostCount: 4}],
+    ])
+  })
+})

src/lib/api/feed-manip.ts

@@ -9,7 +9,7 @@ export type FeedPostNumbering = Pick<
   'opThreadPostIndex' | 'opThreadPostCount'
 >
 
-type ValidFeedPostNumbering = Required<FeedPostNumbering>
+export type ValidFeedPostNumbering = Required<FeedPostNumbering>
 
 // AppView adds these fields to feed responses ahead of their feed lexicon.
 type FeedViewPost = app.bsky.feed.defs.FeedViewPost & FeedPostNumbering
@@ -62,7 +62,7 @@ export type FeedTunerFn = (
 type FeedSliceItem = {
   post: app.bsky.feed.defs.PostView
   record: app.bsky.feed.post.Main
-  postNumbering: FeedPostNumbering | undefined
+  postNumbering: ValidFeedPostNumbering | undefined
   parentAuthor: app.bsky.actor.defs.ProfileViewBasic | undefined
   isParentBlocked: boolean
   isParentNotFound: boolean
@@ -88,7 +88,7 @@ export class FeedViewPostsSlice {
 
   constructor(
     feedPost: FeedViewPost,
-    postNumberingByUri: Map<string, FeedPostNumbering>,
+    postNumberingByUri: Map<string, ValidFeedPostNumbering>,
   ) {
     const {post, reply, reason} = feedPost
     this.items = []
@@ -286,6 +286,22 @@ export class FeedViewPostsSlice {
   }
 }
 
+export function createFeedViewPostsSlices(
+  feed: FeedViewPost[],
+): FeedViewPostsSlice[] {
+  const postNumberingByUri = new Map<string, ValidFeedPostNumbering>()
+  for (const item of feed) {
+    const postNumbering = getPostNumbering(item)
+    if (postNumbering) {
+      postNumberingByUri.set(item.post.uri, postNumbering)
+    }
+  }
+
+  return feed
+    .map(item => new FeedViewPostsSlice(item, postNumberingByUri))
+    .filter(slice => slice.items.length > 0 || slice.isFallbackMarker)
+}
+
 export class FeedTuner {
   seenKeys: Set<string> = new Set()
   seenUris: Set<string> = new Set()
@@ -299,17 +315,7 @@ export class FeedTuner {
       dryRun: false,
     },
   ): FeedViewPostsSlice[] {
-    const postNumberingByUri = new Map<string, FeedPostNumbering>()
+    let slices = createFeedViewPostsSlices(feed)
-    for (const item of feed) {
-      const postNumbering = getPostNumbering(item)
-      if (postNumbering) {
-        postNumberingByUri.set(item.post.uri, postNumbering)
-      }
-    }
-
-    let slices: FeedViewPostsSlice[] = feed
-      .map(item => new FeedViewPostsSlice(item, postNumberingByUri))
-      .filter(s => s.items.length > 0 || s.isFallbackMarker)
 
     // run the custom tuners
     for (const tunerFn of this.tunerFns) {

src/state/queries/explore-feed-previews.tsx

@@ -11,7 +11,11 @@ import {
 
 import {CustomFeedAPI} from '#/lib/api/feed/custom'
 import {aggregateUserInterests} from '#/lib/api/feed/utils'
-import {FeedTuner} from '#/lib/api/feed-manip'
+import {
+  createFeedViewPostsSlices,
+  FeedTuner,
+  type ValidFeedPostNumbering,
+} from '#/lib/api/feed-manip'
 import {cleanError} from '#/lib/strings/errors'
 import {useModerationOpts} from '#/state/preferences/moderation-opts'
 import {
@@ -403,6 +407,35 @@ export function* findAllPostsInQueryData(
   }
 }
 
+export function findPostNumberingInQueryData(
+  queryClient: QueryClient,
+  uri: string,
+): ValidFeedPostNumbering | undefined {
+  const atUri = new AtUri(uri)
+  const queryDatas = queryClient.getQueriesData<
+    InfiniteData<{
+      feed: app.bsky.feed.defs.GeneratorView
+      posts: app.bsky.feed.defs.FeedViewPost[]
+    }>
+  >({
+    queryKey: [RQKEY_ROOT],
+  })
+
+  for (const [_queryKey, queryData] of queryDatas) {
+    if (!queryData?.pages) continue
+
+    for (const page of queryData.pages) {
+      for (const slice of createFeedViewPostsSlices(page.posts)) {
+        for (const item of slice.items) {
+          if (item.postNumbering && didOrHandleUriMatches(atUri, item.post)) {
+            return item.postNumbering
+          }
+        }
+      }
+    }
+  }
+}
+
 export function* findAllProfilesInQueryData(
   queryClient: QueryClient,
   did: string,

src/state/queries/post-feed.ts

@@ -26,9 +26,11 @@ import {PostListFeedAPI} from '#/lib/api/feed/posts'
 import {type FeedAPI, type ReasonFeedSource} from '#/lib/api/feed/types'
 import {aggregateUserInterests} from '#/lib/api/feed/utils'
 import {
+  createFeedViewPostsSlices,
   type FeedPostNumbering,
   FeedTuner,
   type FeedTunerFn,
+  type ValidFeedPostNumbering,
 } from '#/lib/api/feed-manip'
 import {DISCOVER_FEED_URI} from '#/lib/constants'
 import {logger} from '#/logger'
@@ -527,6 +529,32 @@ export function* findAllPostsInQueryData(
   }
 }
 
+export function findPostNumberingInQueryData(
+  queryClient: QueryClient,
+  uri: string,
+): ValidFeedPostNumbering | undefined {
+  const atUri = new AtUri(uri)
+  const queryDatas = queryClient.getQueriesData<
+    InfiniteData<FeedPageUnselected>
+  >({
+    queryKey: [RQKEY_ROOT],
+  })
+
+  for (const [_queryKey, queryData] of queryDatas) {
+    if (!queryData?.pages) continue
+
+    for (const page of queryData.pages) {
+      for (const slice of createFeedViewPostsSlices(page.feed)) {
+        for (const item of slice.items) {
+          if (item.postNumbering && didOrHandleUriMatches(atUri, item.post)) {
+            return item.postNumbering
+          }
+        }
+      }
+    }
+  }
+}
+
 export function* findAllProfilesInQueryData(
   queryClient: QueryClient,
   did: string,

src/state/queries/usePostThread/queryCache.test.ts

@@ -0,0 +1,117 @@
+import {QueryClient} from '@tanstack/react-query'
+
+import {findAllPostsInQueryData as findAllPostsInBookmarksQueryData} from '#/state/queries/bookmarks/useBookmarksQuery'
+import {
+  findAllPostsInQueryData as findAllPostsInExploreFeedPreviewsQueryData,
+  findPostNumberingInQueryData as findPostNumberingInExploreFeedPreviewsQueryData,
+} from '#/state/queries/explore-feed-previews'
+import {findAllPostsInQueryData as findAllPostsInNotifsQueryData} from '#/state/queries/notifications/feed'
+import {
+  findAllPostsInQueryData as findAllPostsInFeedQueryData,
+  findPostNumberingInQueryData as findPostNumberingInFeedQueryData,
+} from '#/state/queries/post-feed'
+import {findAllPostsInQueryData as findAllPostsInQuoteQueryData} from '#/state/queries/post-quotes'
+import {findAllPostsInQueryData as findAllPostsInSearchQueryData} from '#/state/queries/search-posts-v2'
+import {type app} from '#/lexicons'
+import {getThreadPlaceholder} from './queryCache'
+
+jest.mock('#/state/cache/post-shadow', () => ({
+  dangerousGetPostShadow: jest.fn(),
+  updatePostShadow: jest.fn(),
+}))
+jest.mock('#/state/queries/bookmarks/useBookmarksQuery', () => ({
+  findAllPostsInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/explore-feed-previews', () => ({
+  findAllPostsInQueryData: jest.fn(),
+  findPostNumberingInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/notifications/feed', () => ({
+  findAllPostsInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/post-feed', () => ({
+  findAllPostsInQueryData: jest.fn(),
+  findPostNumberingInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/post-quotes', () => ({
+  findAllPostsInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/search-posts-v2', () => ({
+  findAllPostsInQueryData: jest.fn(),
+}))
+jest.mock('#/state/queries/usePostThread', () => ({
+  usePostThreadContext: jest.fn(),
+}))
+
+const finders = [
+  findAllPostsInBookmarksQueryData,
+  findAllPostsInExploreFeedPreviewsQueryData,
+  findAllPostsInNotifsQueryData,
+  findAllPostsInFeedQueryData,
+  findAllPostsInQuoteQueryData,
+  findAllPostsInSearchQueryData,
+]
+
+function post(uri: string, likeCount: number) {
+  return {
+    $type: 'app.bsky.feed.defs#postView',
+    uri,
+    likeCount,
+  } as app.bsky.feed.defs.PostView
+}
+
+describe('getThreadPlaceholder', () => {
+  const queryClient = new QueryClient()
+
+  beforeEach(() => {
+    jest.resetAllMocks()
+    for (const finder of finders) {
+      jest.mocked(finder).mockImplementation(function* () {})
+    }
+    jest.mocked(findPostNumberingInFeedQueryData).mockReturnValue(undefined)
+    jest
+      .mocked(findPostNumberingInExploreFeedPreviewsQueryData)
+      .mockReturnValue(undefined)
+  })
+
+  it('combines feed numbering with the preferred cached post', () => {
+    const uri = 'at://did:plc:alice/app.bsky.feed.post/1'
+    const notificationPost = post(uri, 4)
+    const feedPost = post(uri, 1)
+    jest.mocked(findPostNumberingInFeedQueryData).mockReturnValue({
+      opThreadPostIndex: 2,
+      opThreadPostCount: 4,
+    })
+    jest.mocked(findAllPostsInNotifsQueryData).mockImplementation(function* () {
+      yield notificationPost
+      return undefined
+    })
+    jest.mocked(findAllPostsInFeedQueryData).mockImplementation(function* () {
+      yield feedPost
+      return undefined
+    })
+
+    const placeholder = getThreadPlaceholder(queryClient, uri)
+
+    expect(placeholder?.value).toMatchObject({
+      post: notificationPost,
+      opThread: true,
+      opThreadPostIndex: 2,
+      opThreadPostCount: 4,
+    })
+  })
+
+  it('keeps non-numbered placeholders out of the OP thread', () => {
+    const uri = 'at://did:plc:alice/app.bsky.feed.post/1'
+    jest.mocked(findAllPostsInFeedQueryData).mockImplementation(function* () {
+      yield post(uri, 1)
+      return undefined
+    })
+
+    const placeholder = getThreadPlaceholder(queryClient, uri)
+
+    expect(placeholder?.value).toMatchObject({opThread: false})
+    expect(placeholder?.value).not.toHaveProperty('opThreadPostIndex')
+    expect(placeholder?.value).not.toHaveProperty('opThreadPostCount')
+  })
+})

src/state/queries/usePostThread/queryCache.ts

@@ -3,14 +3,21 @@ import {type $Typed} from '@atproto/lex'
 import {AtUri} from '@atproto/syntax'
 import {type QueryClient, useQueryClient} from '@tanstack/react-query'
 
+import {type ValidFeedPostNumbering} from '#/lib/api/feed-manip'
 import {
   dangerousGetPostShadow,
   updatePostShadow,
 } from '#/state/cache/post-shadow'
 import {findAllPostsInQueryData as findAllPostsInBookmarksQueryData} from '#/state/queries/bookmarks/useBookmarksQuery'
-import {findAllPostsInQueryData as findAllPostsInExploreFeedPreviewsQueryData} from '#/state/queries/explore-feed-previews'
+import {
+  findAllPostsInQueryData as findAllPostsInExploreFeedPreviewsQueryData,
+  findPostNumberingInQueryData as findPostNumberingInExploreFeedPreviewsQueryData,
+} from '#/state/queries/explore-feed-previews'
 import {findAllPostsInQueryData as findAllPostsInNotifsQueryData} from '#/state/queries/notifications/feed'
-import {findAllPostsInQueryData as findAllPostsInFeedQueryData} from '#/state/queries/post-feed'
+import {
+  findAllPostsInQueryData as findAllPostsInFeedQueryData,
+  findPostNumberingInQueryData as findPostNumberingInFeedQueryData,
+} from '#/state/queries/post-feed'
 import {findAllPostsInQueryData as findAllPostsInQuoteQueryData} from '#/state/queries/post-quotes'
 import {findAllPostsInQueryData as findAllPostsInSearchQueryData} from '#/state/queries/search-posts-v2'
 import {usePostThreadContext} from '#/state/queries/usePostThread'
@@ -207,8 +214,15 @@ export function getThreadPlaceholder(
   queryClient: QueryClient,
   uri: string,
 ): $Typed<app.bsky.unspecced.getPostThreadV2.ThreadItem> | void {
+  const postNumbering =
+    findPostNumberingInFeedQueryData(queryClient, uri) ??
+    findPostNumberingInExploreFeedPreviewsQueryData(queryClient, uri)
   let partial
-  for (let item of getThreadPlaceholderCandidates(queryClient, uri)) {
+  for (let item of getThreadPlaceholderCandidates(
+    queryClient,
+    uri,
+    postNumbering,
+  )) {
     /*
      * Currently, the backend doesn't send full post info in some cases (for
      * example, for quoted posts). We use missing `likeCount` as a way to
@@ -231,6 +245,7 @@ export function getThreadPlaceholder(
 export function* getThreadPlaceholderCandidates(
   queryClient: QueryClient,
   uri: string,
+  postNumbering?: ValidFeedPostNumbering,
 ): Generator<
   $Typed<
     Omit<app.bsky.unspecced.getPostThreadV2.ThreadItem, 'value'> & {
@@ -243,7 +258,7 @@ export function* getThreadPlaceholderCandidates(
    * Check post thread queries first
    */
   for (const post of findAllPostsInQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
 
   /*
@@ -253,25 +268,25 @@ export function* getThreadPlaceholderCandidates(
    * avoid a notification->post scroll jump.
    */
   for (let post of findAllPostsInNotifsQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
   for (let post of findAllPostsInFeedQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
   for (let post of findAllPostsInQuoteQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
   for (let post of findAllPostsInSearchQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
   for (let post of findAllPostsInBookmarksQueryData(queryClient, uri)) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
   for (let post of findAllPostsInExploreFeedPreviewsQueryData(
     queryClient,
     uri,
   )) {
-    yield postViewToThreadPlaceholder(post)
+    yield postViewToThreadPlaceholder(post, postNumbering)
   }
 }
 

src/state/queries/usePostThread/views.ts

@@ -2,6 +2,7 @@ import {type $Typed} from '@atproto/lex'
 import {AtUri} from '@atproto/syntax'
 import {moderatePost, type ModerationOpts} from '@bsky/sdk/moderation'
 
+import {type ValidFeedPostNumbering} from '#/lib/api/feed-manip'
 import {makeProfileLink} from '#/lib/routes/links'
 import {
   type ApiThreadItem,
@@ -156,6 +157,7 @@ export function skeleton({
 
 export function postViewToThreadPlaceholder(
   post: app.bsky.feed.defs.PostView,
+  postNumbering?: ValidFeedPostNumbering,
 ): $Typed<
   Omit<app.bsky.unspecced.getPostThreadV2.ThreadItem, 'value'> & {
     value: $Typed<app.bsky.unspecced.defs.ThreadItemPost>
@@ -168,7 +170,8 @@ export function postViewToThreadPlaceholder(
     value: {
       $type: 'app.bsky.unspecced.defs#threadItemPost',
       post,
-      opThread: false,
+      opThread: !!postNumbering,
+      ...postNumbering,
       moreParents: false,
       moreReplies: 0,
       hiddenByThreadgate: false,