fix: resolve in_reply_to_account_id for Phanpy reply threading

Phanpy uses in_reply_to_account_id to show "Replying to @user" context.
Without it, replies appear as standalone posts in the timeline.

resolveReplyIds now returns both replyIdMap and replyAccountIdMap.
Account IDs computed via remoteActorId(author.url) — same deterministic
hash used by the account entity serializer.

lib/mastodon/entities/status.js

@@ -44,7 +44,7 @@ export function setLocalIdentity(publicationUrl, handle) {
  * @param {Set<string>} [options.pinnedIds] - UIDs the user has pinned
  * @returns {object} Mastodon Status entity
  */
-export function serializeStatus(item, { baseUrl, favouritedIds, rebloggedIds, bookmarkedIds, pinnedIds, replyIdMap } = {}) {
+export function serializeStatus(item, { baseUrl, favouritedIds, rebloggedIds, bookmarkedIds, pinnedIds, replyIdMap, replyAccountIdMap } = {}) {
   if (!item) return null;
 
   // Use published-based cursor as the status ID so pagination cursors
@@ -205,7 +205,7 @@ export function serializeStatus(item, { baseUrl, favouritedIds, rebloggedIds, bo
     id,
     created_at: published,
     in_reply_to_id: replyIdMap?.get(item.inReplyTo) ?? null,
-    in_reply_to_account_id: null,
+    in_reply_to_account_id: replyAccountIdMap?.get(item.inReplyTo) ?? null,
     sensitive,
     spoiler_text: spoilerText,
     visibility,

lib/mastodon/helpers/resolve-reply-ids.js

@@ -1,19 +1,23 @@
 /**
- * Batch-resolve inReplyTo URLs to Mastodon cursor IDs.
+ * Batch-resolve inReplyTo URLs to Mastodon cursor IDs and account IDs.
+ *
+ * Looks up parent posts in ap_timeline by uid/url and returns two Maps:
+ * - replyIdMap: inReplyTo URL → cursor ID (status ID)
+ * - replyAccountIdMap: inReplyTo URL → author account ID
  *
- * Looks up parent posts in ap_timeline by uid/url and returns a Map
- * of inReplyTo URL → cursor ID (milliseconds since epoch as string).
  * Used by route handlers before calling serializeStatus().
  *
  * @param {object} collection - ap_timeline MongoDB collection
  * @param {Array<object>} items - Timeline items with optional inReplyTo
- * @returns {Promise<Map<string, string>>} Map of URL → cursor ID
+ * @returns {Promise<{replyIdMap: Map<string, string>, replyAccountIdMap: Map<string, string>}>}
  */
 import { encodeCursor } from "./pagination.js";
+import { remoteActorId } from "./id-mapping.js";
 
 export async function resolveReplyIds(collection, items) {
-  const map = new Map();
-  if (!collection || !items?.length) return map;
+  const replyIdMap = new Map();
+  const replyAccountIdMap = new Map();
+  if (!collection || !items?.length) return { replyIdMap, replyAccountIdMap };
 
   // Collect unique inReplyTo URLs
   const urls = [
@@ -23,22 +27,27 @@ export async function resolveReplyIds(collection, items) {
         .filter(Boolean),
     ),
   ];
-  if (urls.length === 0) return map;
+  if (urls.length === 0) return { replyIdMap, replyAccountIdMap };
 
   // Batch lookup parents by uid or url
   const parents = await collection
     .find({ $or: [{ uid: { $in: urls } }, { url: { $in: urls } }] })
-    .project({ uid: 1, url: 1, published: 1 })
+    .project({ uid: 1, url: 1, published: 1, "author.url": 1 })
     .toArray();
 
   for (const parent of parents) {
     const cursorId = encodeCursor(parent.published);
-    if (cursorId && cursorId !== "0") {
-      // Map both uid and url to the cursor ID
-      if (parent.uid) map.set(parent.uid, cursorId);
-      if (parent.url && parent.url !== parent.uid) map.set(parent.url, cursorId);
-    }
+    const authorUrl = parent.author?.url;
+    const authorAccountId = authorUrl ? remoteActorId(authorUrl) : null;
+
+    const setMaps = (key) => {
+      if (cursorId && cursorId !== "0") replyIdMap.set(key, cursorId);
+      if (authorAccountId) replyAccountIdMap.set(key, authorAccountId);
+    };
+
+    if (parent.uid) setMaps(parent.uid);
+    if (parent.url && parent.url !== parent.uid) setMaps(parent.url);
   }
 
-  return map;
+  return { replyIdMap, replyAccountIdMap };
 }

lib/mastodon/routes/statuses.js

@@ -44,13 +44,14 @@ router.get("/api/v1/statuses/:id", tokenRequired, scopeRequired("read", "read:st
 
     // Load interaction state if authenticated
     const interactionState = await loadItemInteractions(collections, item);
-    const replyIdMap = await resolveReplyIds(collections.ap_timeline, [item]);
+    const { replyIdMap, replyAccountIdMap } = await resolveReplyIds(collections.ap_timeline, [item]);
 
     const status = serializeStatus(item, {
       baseUrl,
       ...interactionState,
       pinnedIds: new Set(),
       replyIdMap,
+      replyAccountIdMap,
     });
 
     res.json(status);
@@ -126,8 +127,8 @@ router.get("/api/v1/statuses/:id/context", tokenRequired, scopeRequired("read",
     };
 
     const allItems = [...ancestors, ...descendants];
-    const replyIdMap = await resolveReplyIds(collections.ap_timeline, allItems);
-    const serializeOpts = { baseUrl, ...emptyInteractions, replyIdMap };
+    const { replyIdMap, replyAccountIdMap } = await resolveReplyIds(collections.ap_timeline, allItems);
+    const serializeOpts = { baseUrl, ...emptyInteractions, replyIdMap, replyAccountIdMap };
 
     res.json({
       ancestors: ancestors.map((a) => serializeStatus(a, serializeOpts)),

lib/mastodon/routes/timelines.js

@@ -65,7 +65,7 @@ router.get("/api/v1/timelines/home", tokenRequired, scopeRequired("read", "read:
     );
 
     // Resolve reply parent IDs for threading
-    const replyIdMap = await resolveReplyIds(collections.ap_timeline, items);
+    const { replyIdMap, replyAccountIdMap } = await resolveReplyIds(collections.ap_timeline, items);
 
     // Serialize to Mastodon Status entities
     const statuses = items.map((item) =>
@@ -76,6 +76,7 @@ router.get("/api/v1/timelines/home", tokenRequired, scopeRequired("read", "read:
         bookmarkedIds,
         pinnedIds: new Set(),
         replyIdMap,
+        replyAccountIdMap,
       }),
     );
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@rmdes/indiekit-endpoint-activitypub",
-  "version": "3.11.6",
+  "version": "3.11.7",
   "description": "ActivityPub federation endpoint for Indiekit via Fedify. Adds full fediverse support: actor, inbox, outbox, followers, following, syndication, and Mastodon migration.",
   "keywords": [
     "indiekit",