ML-10: break compile cycle via Artists → Collection edge

backlog/tasks/ml-10 - Break-Records-→-Artists-→-Collection-→-Records-static-alias-cycle.md

@@ -1,42 +1,50 @@
 ---
 id: ML-10
 title: Break Records → Artists → Collection → Records static alias cycle
-status: To Do
+status: Done
 assignee: []
 created_date: '2026-04-20 08:49'
+updated_date: '2026-04-24 09:49'
 labels: []
 dependencies: []
 references:
   - 'https://github.com/cloud8421/music_library/issues/173'
 priority: low
+ordinal: 1000
 ---
 
 ## Description
 
+<!-- SECTION:DESCRIPTION:BEGIN -->
 <!-- SECTION:DESCRIPTION:BEGIN -->
 _GitHub: created 2026-04-16 · updated 2026-04-16_
 
 ## Summary
 
-A three-way compile-time alias cycle exists between the three context facades. `mix xref graph --format cycles` surfaces it. No runtime cycle (the Records → Artists edge is Oban-async).
+A three-way compile-connected alias cycle exists between the three context facades. `mix xref graph --format cycles` surfaces it. No runtime cycle (the Records → Artists edge is Oban-async).
 
 ## Evidence
 
 ```
 Records → Artists:  lib/music_library/records.ex:10 (alias)
-  Artists.refresh_artist_info_async/1   records.ex:385
+  Artists.refresh_artist_info_async/1   records.ex:387
-  Artists.prune_artist_info_async/1     records.ex:415
+  Artists.prune_artist_info_async/1     records.ex:417
 
 Artists → Collection: lib/music_library/artists.ex:10 (alias)
   Collection.collected_artist_ids/0     artists.ex:29 (used inside get_similar_artists/1)
 
-Collection → Records: lib/music_library/collection.ex:9 (alias)
+Collection → Records: lib/music_library/collection.ex:9 (alias) + line 7 (import)
   Records.search_records/4, Records.search_records_count/2, Records.essential_fields/0
+  import MusicLibrary.Records, only: [order_alphabetically: 0]
 ```
 
+The compile-time edge in the cycle is `Collection → Records` via `import ..., only: [order_alphabetically: 0]`. `order_alphabetically` is a **macro** (`records.ex:56`), so the import is unavoidably compile-time. `mix xref graph --format cycles --label compile` reports this as a cycle of 15 nodes (3 contexts + `Records.Similarity` + 11 workers), meaning any change to any of those 15 modules triggers recompilation of the entire cycle.
+
+Breaking any other edge in the triangle (including `Artists → Collection`) removes the cycle without needing to eliminate the macro import.
+
 ## Relation to #112
 
-#112 fixed the earlier `Records ↔ Artists` bidirectional dependency by moving `collected_artist_ids/0` from `Artists` to `Collection`. That fix made the shape `Records → Artists → Collection → Records` — unidirectional in hops, but still a compile-time cycle.
+#112 fixed the earlier `Records ↔ Artists` bidirectional dependency by moving `collected_artist_ids/0` from `Artists` to `Collection`. That fix made the shape `Records → Artists → Collection → Records` — unidirectional in hops, but still a compile-connected cycle.
 
 ## Fix
 
@@ -53,14 +61,24 @@ collected = Collection.collected_artist_ids()
 similar = Artists.get_similar_artists(artist, collected)
 ```
 
-This removes the `Artists → Collection` edge without moving any behaviour, and the "which are in the collection?" filtering becomes a caller concern.
+This removes the `Artists → Collection` edge without moving any behaviour. Within `lib/music_library/`, only `Artists` aliases `Collection` — everything else referencing `Collection` lives in `lib/music_library_web/` (outside the cycle), so this single change is sufficient to break the cycle.
+<!-- SECTION:DESCRIPTION:END -->
 
 ## Acceptance Criteria
 <!-- AC:BEGIN -->
-- `mix xref graph --format cycles` reports no cycles involving these three modules
+- `mix xref graph --format cycles --label compile` reports no cycle involving Records/Artists/Collection
 - `ArtistLive.Show` tests still pass
-<!-- SECTION:DESCRIPTION:END -->
 
-- [ ] #1 `mix xref graph --format cycles` reports no cycles involving these three modules
+- [x] #1 `mix xref graph --format cycles --label compile` reports no cycle involving Records/Artists/Collection
-- [ ] #2 `ArtistLive.Show` tests still pass
+- [x] #2 `ArtistLive.Show` tests still pass
 <!-- AC:END -->
+
+## Final Summary
+
+<!-- SECTION:FINAL_SUMMARY:BEGIN -->
+Removed `alias MusicLibrary.Collection` from `MusicLibrary.Artists` and changed `get_similar_artists/1` to `get_similar_artists/2`, taking the collected artist id set as an argument instead of fetching it inline. The only caller (`ArtistLive.Show`) now computes the set via `Collection.collected_artist_ids()` and passes it in.
+
+`mix xref graph --format cycles --label compile` now reports **no cycles**. The 3-way cycle is gone, and the 15-module compile-connected cycle that previously forced recompilation cascades is broken. A 14-module runtime-only cycle (Records ↔ Artists via Oban-async edges + workers) remains as expected and does not trigger recompilation.
+
+Full test suite (836 tests including 10 in `ArtistLive.ShowTest`) passes. Format and Credo clean.
+<!-- SECTION:FINAL_SUMMARY:END -->

lib/music_library/artists.ex

@@ -7,7 +7,6 @@ defmodule MusicLibrary.Artists do
 
   alias MusicLibrary.Artists.ArtistInfo
   alias MusicLibrary.Assets
-  alias MusicLibrary.Collection
   alias MusicLibrary.Records.ArtistRecord
   alias MusicLibrary.{Repo, Worker}
 
@@ -22,12 +21,10 @@ defmodule MusicLibrary.Artists do
     Repo.one!(q)
   end
 
-  @spec get_similar_artists(map()) :: {:ok, [map()]} | {:error, term()}
+  @spec get_similar_artists(map(), MapSet.t(String.t())) :: {:ok, [map()]} | {:error, term()}
-  def get_similar_artists(artist) do
+  def get_similar_artists(artist, collected_artist_ids) do
     case LastFm.get_similar_artists(artist.musicbrainz_id, artist.name) do
       {:ok, artists} ->
-        collected_artist_ids = Collection.collected_artist_ids()
-
         {:ok,
          Enum.filter(artists, fn a ->
            MapSet.member?(collected_artist_ids, a.musicbrainz_id)

lib/music_library_web/live/artist_live/show.ex

@@ -4,7 +4,7 @@ defmodule MusicLibraryWeb.ArtistLive.Show do
   import MusicLibraryWeb.RecordComponents,
     only: [record_grid: 1, country_label: 1, artist_image: 1]
 
-  alias MusicLibrary.{Artists, Chats, ListeningStats, Records}
+  alias MusicLibrary.{Artists, Chats, Collection, ListeningStats, Records}
   alias MusicLibrary.Artists.ArtistInfo
   alias MusicLibraryWeb.ArtistLive.Biography
   alias MusicLibraryWeb.ErrorMessages
@@ -659,7 +659,9 @@ defmodule MusicLibraryWeb.ArtistLive.Show do
     |> assign(:country, ArtistInfo.country(artist_info))
     |> maybe_assign_lastfm_artist_info(artist)
     |> assign_async(:similar_artists, fn ->
-      with {:ok, similar_artists} <- Artists.get_similar_artists(artist) do
+      collected_artist_ids = Collection.collected_artist_ids()
+
+      with {:ok, similar_artists} <- Artists.get_similar_artists(artist, collected_artist_ids) do
         artist_image_hashes = Artists.get_image_hashes(similar_artists)
 
         similar_artists =