v4: a playlist's dump count is of the dumps the viewer may see — it counted every dump in the playlist, so a card said "3 dumps" over a page listing two, and told everyone how many private dumps a playlist held. The lists (/playlists, a profile's playlists and followed ones, the search, a dump's playlists, the add-to-playlist panel) now count by isMemberVisibleTo's rule, in SQL as VISIBLE_DUMP_COUNT (lib/playlist-members.ts): the public dumps, and for the owner their own private ones. GET /api/playlists and /api/users/:key/follow/playlists read the optional sign-in for it. The community page and the digests count the public dumps, their figures being the same for every reader. Live, playlist_created and playlist_updated carry each socket's own count: broadcastChange builds the owner's message and the others' apart. playlist_dumps_updated loses its dumpCount, a client counting the dumps it is sent.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/test/routes/playlists.test.ts

@@ -146,6 +146,72 @@ test("a public playlist hides its private dumps from everyone but their owner",
   );
 });
 
+test("a playlist's dumpCount is of the dumps the viewer may see", async () => {
+  const owner = await createUser();
+  const author = await createUser();
+  const pl = insertPlaylist({ userId: owner.id, title: "Counted banana" });
+  const pub = insertDump({ userId: owner.id });
+  const mine = insertDump({ userId: owner.id, isPrivate: true });
+  // Someone else's, gone private after it was added: its owner no longer
+  // sees it there, and neither does its poster.
+  const theirs = insertDump({ userId: author.id, isPrivate: true });
+  for (const [i, d] of [pub, mine, theirs].entries()) {
+    db.prepare(
+      `INSERT INTO playlist_dumps (playlist_id, dump_id, position, added_at)
+       VALUES (?, ?, ?, ?);`,
+    ).run(pl.id, d.id, i, new Date().toISOString());
+  }
+  await put(`/api/me/follow/playlists/${pl.id}`, { auth: author.auth });
+
+  const lists = [
+    "/api/playlists",
+    `/api/users/@${owner.username}/playlists`,
+    `/api/users/@${author.username}/follow/playlists`,
+  ];
+  for (
+    const [auth, expected] of [
+      [owner.auth, 2],
+      [author.auth, 1],
+      [undefined, 1],
+    ] as const
+  ) {
+    for (const url of lists) {
+      const { items } = (await get<PaginatedData<Playlist>>(url, { auth }))
+        .data;
+      assertEquals(items.map((p) => p.dumpCount), [expected], url);
+    }
+    assertEquals(
+      (await get<{ playlists: Playlist[] }>("/api/search?q=banana", { auth }))
+        .data.playlists.map((p) => p.dumpCount),
+      [expected],
+    );
+    assertEquals(
+      (await get<Playlist[]>(`/api/dumps/${pub.id}/playlists`, { auth })).data
+        .map((p) => p.dumpCount),
+      [expected],
+    );
+    const page = await get<PlaylistWithDumps>(`/api/playlists/${pl.id}`, {
+      auth,
+    });
+    assertEquals(page.data.dumpCount, expected);
+    assertEquals(ids(page).length, expected);
+  }
+  assertEquals(
+    (await get<PlaylistMembership[]>(`/api/me/playlists?contains=${pub.id}`, {
+      auth: owner.auth,
+    })).data.map((m) => [m.hasDump, m.playlist.dumpCount]),
+    [[true, 2]],
+  );
+  // An edit answers with the editor's count.
+  assertEquals(
+    (await put<Playlist>(`/api/playlists/${pl.id}`, {
+      auth: owner.auth,
+      json: { title: "Counted" },
+    })).data.dumpCount,
+    2,
+  );
+});
+
 test("reorder: must name exactly the current members", async () => {
   const owner = await createUser();
   const { id } = insertPlaylist({ userId: owner.id });