feat(post-api): get_post returns uncapped thumbnails — PostModal masonry needs full image list; feed query unchanged (still capped at 6 for previews). _thumbnails_for gains a limit kwarg; get_post passes limit=None.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/services/post_feed_service.py

@@ -109,7 +109,10 @@ class PostFeedService:
         if row is None:
             return None
         post, artist, source = row
-        thumbs_map = await self._thumbnails_for([post.id])
+        # Detail endpoint returns the FULL image list for PostModal's
+        # masonry grid — feed query still caps at THUMBNAIL_LIMIT via
+        # the default arg.
+        thumbs_map = await self._thumbnails_for([post.id], limit=None)
         atts_map = await self._attachments_for([post.id])
         item = self._to_dict(post, artist, source, thumbs_map, atts_map)
         item["description_full"] = html_to_plain(post.description)
@@ -117,15 +120,21 @@ class PostFeedService:
 
     # --- composition helpers ---------------------------------------------
 
-    async def _thumbnails_for(self, post_ids: list[int]) -> dict[int, dict]:
-        """post_id -> {"thumbs": [...up to 6], "more": int}.
+    async def _thumbnails_for(
+        self, post_ids: list[int], *, limit: int | None = THUMBNAIL_LIMIT,
+    ) -> dict[int, dict]:
+        """post_id -> {"thumbs": [...up to limit], "more": int}.
 
-        Selects THUMBNAIL_LIMIT+1 images per post via window function so we
-        can detect overflow in a single query.
+        Selects up to `limit` images per post via window function so we
+        can detect overflow in a single query. Pass `limit=None` to
+        return ALL thumbnails per post (used by `get_post` for PostModal's
+        masonry grid; the feed pass keeps the default cap so payloads
+        stay small).
         """
         if not post_ids:
             return {}
-        # Rank images within each post and fetch only the top THUMBNAIL_LIMIT+1.
+        # Rank images within each post; cap at `limit` rows per post when
+        # limit is set, return all when limit is None.
         ranked = (
             select(
                 ImageRecord.id,
@@ -143,12 +152,13 @@ class PostFeedService:
             .where(ImageRecord.primary_post_id.in_(post_ids))
             .subquery()
         )
-        rows = (await self.session.execute(
-            select(
-                ranked.c.id, ranked.c.primary_post_id,
-                ranked.c.sha256, ranked.c.mime, ranked.c.total,
-            ).where(ranked.c.rn <= THUMBNAIL_LIMIT)
-        )).all()
+        stmt = select(
+            ranked.c.id, ranked.c.primary_post_id,
+            ranked.c.sha256, ranked.c.mime, ranked.c.total,
+        )
+        if limit is not None:
+            stmt = stmt.where(ranked.c.rn <= limit)
+        rows = (await self.session.execute(stmt)).all()
 
         out: dict[int, dict] = {pid: {"thumbs": [], "more": 0} for pid in post_ids}
         for img_id, pid, sha, mime, total in rows:

tests/test_api_posts.py

@@ -117,3 +117,50 @@ async def test_detail_404_for_unknown(client):
     assert resp.status_code == 404
     body = await resp.get_json()
     assert body["error"] == "not_found"
+
+
+@pytest.mark.asyncio
+async def test_detail_returns_uncapped_thumbnails(client, db):
+    """Feed query caps thumbnails at 6 for previews; detail endpoint
+    returns the full list so PostModal can render the masonry grid."""
+    from backend.app.models import ImageRecord
+
+    a = Artist(name="yuki-api", slug="yuki-api")
+    db.add(a)
+    await db.flush()
+    s = Source(
+        artist_id=a.id, platform="patreon",
+        url="https://patreon.com/cw/yuki-api", enabled=True,
+    )
+    db.add(s)
+    await db.flush()
+    p = Post(
+        source_id=s.id, external_post_id="DETAIL10",
+        post_title="big post", description="<p>body</p>",
+    )
+    db.add(p)
+    await db.flush()
+    # Seed 10 ImageRecord rows linked to this post via primary_post_id.
+    for i in range(10):
+        sha = f"y{i:x}".ljust(64, "0")[:64]
+        rec = ImageRecord(
+            path=f"/images/test-yuki-{i}.jpg",
+            sha256=sha,
+            size_bytes=1,
+            mime="image/jpeg",
+            width=64,
+            height=64,
+            origin="downloaded",
+            integrity_status="unknown",
+            primary_post_id=p.id,
+            artist_id=a.id,
+        )
+        db.add(rec)
+    await db.commit()
+
+    resp = await client.get(f"/api/posts/{p.id}")
+    assert resp.status_code == 200
+    body = await resp.get_json()
+    # Detail returns ALL 10 thumbnails (feed would return 6 + thumbnails_more).
+    assert len(body["thumbnails"]) == 10
+    assert body["description_full"] == "body"