Fix AP re-publish: use versioned object IDs after Delete

After Delete + re-Create, Mastodon tombstones the old object ID and
ignores new Creates with the same ID. Now appends /v2, /v3 etc. so
remote servers treat re-publishes as fresh posts.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

services/federation_impl.py

@@ -288,6 +288,20 @@ class SqlFederationService:
         ).scalars().first()
         return _activity_to_dto(a) if a else None
 
+    async def count_activities_for_source(
+        self, session: AsyncSession, source_type: str, source_id: int,
+        *, activity_type: str,
+    ) -> int:
+        from sqlalchemy import func
+        result = await session.execute(
+            select(func.count()).select_from(APActivity).where(
+                APActivity.source_type == source_type,
+                APActivity.source_id == source_id,
+                APActivity.activity_type == activity_type,
+            )
+        )
+        return result.scalar_one()
+
     # -- Followers ------------------------------------------------------------
 
     async def get_followers(

services/federation_publish.py

@@ -56,13 +56,25 @@ async def try_publish(
     elif activity_type in ("Delete", "Update"):
         return  # never published, nothing to delete/update
 
-    # Stable object ID: same source always gets the same object id so
-    # Mastodon treats Create/Update/Delete as the same post.
+    # Stable object ID within a publish cycle.  After Delete + re-Create
+    # we append a version suffix so remote servers (Mastodon) treat it as
+    # a brand-new post rather than ignoring the tombstoned ID.
     domain = os.getenv("AP_DOMAIN", "rose-ash.com")
-    object_data["id"] = (
+    base_object_id = (
         f"https://{domain}/users/{actor.preferred_username}"
         f"/objects/{source_type.lower()}/{source_id}"
     )
+    if activity_type == "Create" and existing and existing.activity_type == "Delete":
+        # Count prior Creates to derive a version number
+        create_count = await services.federation.count_activities_for_source(
+            session, source_type, source_id, activity_type="Create",
+        )
+        object_data["id"] = f"{base_object_id}/v{create_count + 1}"
+    elif activity_type in ("Update", "Delete") and existing and existing.object_data:
+        # Use the same object ID as the most recent activity
+        object_data["id"] = existing.object_data.get("id", base_object_id)
+    else:
+        object_data["id"] = base_object_id
 
     try:
         await services.federation.publish_activity(

services/stubs.py

@@ -217,6 +217,9 @@ class StubFederationService:
     async def get_activity_for_source(self, session, source_type, source_id):
         return None
 
+    async def count_activities_for_source(self, session, source_type, source_id, *, activity_type):
+        return 0
+
     async def get_followers(self, session, username):
         return []