From 9f02e12414f7f53279f1474ed12bc835fc18b5c9 Mon Sep 17 00:00:00 2001 From: Claudio Ortolina Date: Fri, 22 May 2026 15:37:09 +0100 Subject: [PATCH] ML-169.10: refine implementation plan --- ...ing-optimistic-UI-for-delete-operations.md | 43 +++++++++++-------- 1 file changed, 25 insertions(+), 18 deletions(-) diff --git a/backlog/tasks/ml-169.10 - Fix-Missing-optimistic-UI-for-delete-operations.md b/backlog/tasks/ml-169.10 - Fix-Missing-optimistic-UI-for-delete-operations.md index ef366bd4..ffdd52fb 100644 --- a/backlog/tasks/ml-169.10 - Fix-Missing-optimistic-UI-for-delete-operations.md +++ b/backlog/tasks/ml-169.10 - Fix-Missing-optimistic-UI-for-delete-operations.md @@ -4,7 +4,7 @@ title: "Fix: Async optimistic UI for index/list delete streams" status: To Do assignee: [] created_date: "2026-05-19 11:48" -updated_date: "2026-05-20 10:12" +updated_date: "2026-05-22 14:33" labels: - perf - fix @@ -102,7 +102,7 @@ Per project conventions, `handle_async` always handles three cases: ### 1. `IndexActions.handle_delete/2` — shared path (collection + wishlist) -Replace the synchronous delete with optimistic stream_delete + start_async: +Replace the synchronous delete with optimistic `stream_delete` + `start_async`: ```elixir def handle_delete(socket, id) do @@ -114,7 +114,7 @@ def handle_delete(socket, id) do end ``` -Key: `{:delete_record, id}` as async key ensures uniqueness. The async closure captures `record` — the LiveView task supervisor holds the reference. Do NOT call `load_and_assign_records` — `stream_delete` already removes the item from the stream; a full reload would negate the performance benefit. +Key: `{:delete_record, id}` as async key ensures uniqueness. Do NOT call `load_and_assign_records` — `stream_delete` already removes the item from the stream; a full reload would negate the performance benefit. ### 2. `CollectionLive.Index` — handle_async callbacks @@ -143,12 +143,14 @@ def handle_async({:delete_record, id}, {:exit, _reason}, socket) do end ``` -Note: Both error cases re-fetch via `Records.get_record!(id)`. For `{:error, reason}`, the record was NOT deleted so re-fetch succeeds. For `{:exit, _reason}`, the task crashed — if the record was deleted before the crash, `get_record!` raises `Ecto.NoResultsError` which crashes the LiveView (acceptable: better than silently showing wrong state). +Add `alias MusicLibraryWeb.ErrorMessages` to the module. ### 3. `WishlistLive.Index` — identical handle_async callbacks Duplicate the same three `handle_async` clauses from `CollectionLive.Index`. Per project conventions, extraction at 2 callers is premature; extract to `IndexActions` only when a third index page needs it. +Add `alias MusicLibraryWeb.ErrorMessages` to the module. + ### 4. `ScrobbledTracksLive.Index` — separate async path Replace the synchronous delete handler: @@ -185,6 +187,8 @@ def handle_async({:delete_track, _uts}, {:exit, _reason}, socket) do end ``` +Add `alias MusicLibraryWeb.ErrorMessages` to the module. + Key differences from records path: - Passes `stream_element` through async tuple so rollback uses the exact same map shape without re-running correlated subqueries (audit Finding 7) @@ -192,24 +196,27 @@ Key differences from records path: ### 5. Tests -Currently **zero delete test coverage** across all three index test files. Add: +**Existing coverage to update:** + +Three integration tests exist that test the old synchronous delete path. These must be updated to verify the new async-optimistic behavior (stream_delete + start_async): + +- `collection_live/index_test.exs` — "deletes a record from the listing" +- `wishlist_live/index_test.exs` — "deletes a record from the listing" +- `scrobbled_tracks_live/index_test.exs` — "deletes a scrobbled track from the listing" + +**New tests to add:** | # | Test | File | | --- | ------------------------------------------------------ | --------------------------------------------------- | -| 1 | Delete record from collection grid (success) | `collection_live/index_test.exs` | -| 2 | Delete record from wishlist (success) | `wishlist_live/index_test.exs` | -| 3 | Delete scrobbled track (success) | `scrobbled_tracks_live/index_test.exs` | -| 4 | handle_async `{:ok, {:ok, ...}}` is no-op | `collection_live/index_test.exs` (unit test) | -| 5 | handle_async `{:ok, {:error, ...}}` reinserts + toasts | `collection_live/index_test.exs` (unit test) | -| 6 | handle_async `{:exit, ...}` reinserts + toasts | `collection_live/index_test.exs` (unit test) | -| 7 | handle_async exit uses generic message (not reason) | `collection_live/index_test.exs` (unit test) | -| 8 | `data-confirm` attribute present on delete buttons | `collection_live/index_test.exs` (AC #4 regression) | -| 9 | Show page delete unchanged (still synchronous) | `collection_live/show_test.exs` (AC #5 regression) | +| 1 | handle_async `{:ok, {:ok, ...}}` is no-op | `collection_live/index_test.exs` (unit test) | +| 2 | handle_async `{:ok, {:error, ...}}` reinserts + toasts | `collection_live/index_test.exs` (unit test) | +| 3 | handle_async `{:exit, ...}` reinserts + toasts | `collection_live/index_test.exs` (unit test) | +| 4 | handle_async exit uses generic message (not reason) | `collection_live/index_test.exs` (unit test) | +| 5 | `data-confirm` attribute present on delete buttons | `collection_live/index_test.exs` (AC #4 regression) | +| 6 | Show page delete unchanged (still synchronous) | `collection_live/show_test.exs` (AC #5 regression) | -Integration tests (tests 1-3): click delete button inside dropdown, verify `refute_has` for the record/track ID, verify record is actually deleted from DB via context module. +Unit tests (tests 1-4): import the LiveView module, call `handle_async/3` directly with simulated results, assert socket state (stream contents, toast message). This is the preferred approach for testing failure paths since mocking `Repo.delete` is invasive. -Unit tests (tests 4-7): import the LiveView module, call `handle_async/3` directly with simulated results, assert socket state (stream contents, toast message). This is the preferred approach for testing failure paths since mocking `Repo.delete` is invasive. - -Test 7 specifically asserts that `{:exit, :killed}` produces a generic gettext string, not the raw exit reason — this prevents accidental stacktrace leakage to users. +Test 4 specifically asserts that `{:exit, :killed}` produces a generic gettext string, not the raw exit reason — this prevents accidental stacktrace leakage to users.