music_library/backlog/tasks/ml-174 - Add-menu-action-to-empty-a-set.md

id, title, status, assignee, created_date, updated_date, labels, dependencies, references

id	title	status	assignee	created_date	updated_date	labels	dependencies	references
ML-174	Add menu action to empty a set	To Do		2026-05-09 17:57	2026-05-09 18:05			backlog/docs/doc-16 - Research-Add-menu-action-to-empty-a-set.md

Description

For record sets, it would be useful to empty the set, which means removing all items in the set in one single operation. The action should be available in the dropdown menu already available in each set (both in the index and show views).

Acceptance Criteria

• #1 Clicking "Empty" in the set dropdown (index view) removes all records from that set and the card updates to show 0/0 records
• #2 Clicking "Empty" in the set dropdown (show view) removes all records and the grid clears
• #3 A confirmation prompt appears before emptying the set
• #4 Emptying a set does not delete the set itself (name, description, and metadata are preserved)
• #5 The context function RecordSets.empty_record_set/1 returns {:ok, record_set} with an empty items list

Implementation Plan

Implementation Plan

1. Add empty_record_set/1 to MusicLibrary.RecordSets

Add a new public function that bulk-deletes all RecordSetItem rows for a given set in a single query, then reloads the set.

File: lib/music_library/record_sets.ex

@spec empty_record_set(RecordSet.t()) :: {:ok, RecordSet.t()}
def empty_record_set(%RecordSet{} = record_set) do
  from(i in RecordSetItem, where: i.record_set_id == ^record_set.id)
  |> Repo.delete_all()

  {:ok, get_record_set!(record_set.id)}
end

Rationale: Repo.delete_all issues a single DELETE FROM record_set_items WHERE record_set_id = ? — no N+1 regardless of item count. Only the id field is needed from the struct. Not wrapped in a transaction — consistent with remove_record_from_set/2 and reorder_records_in_set/2.

2. Add "Empty" button and handler to index view

File: lib/music_library_web/live/record_set_live/index.ex

Add a dropdown_button below the separator, grouped with "Delete" (since emptying is a destructive action). Place it between the separator and the existing "Delete" button:

<.dropdown_separator />
<.dropdown_button
  phx-click="empty_set"
  phx-value-id={@record_set.id}
  data-confirm={gettext("Remove all records from this set?")}
>
  {gettext("Empty")}
</.dropdown_button>
<.dropdown_button
  phx-click="delete_set"
  ...
>
  {gettext("Delete")}
</.dropdown_button>

Add handle_event. Pass only the ID via a minimal struct to avoid a redundant get_record_set! call (the function itself does the reload):

def handle_event("empty_set", %{"id" => id}, socket) do
  {:ok, updated_set} = RecordSets.empty_record_set(%RecordSet{id: id})
  {:noreply, update_record_set_in_list(socket, updated_set)}
end

3. Add "Empty" button and handler to show view

File: lib/music_library_web/live/record_set_live/show.ex

Add the same dropdown_button below the separator, before "Delete" (same placement as index). Add handle_event with a success toast for consistency with delete_set:

def handle_event("empty_set", _params, socket) do
  {:ok, updated_set} = RecordSets.empty_record_set(socket.assigns.record_set)
  {:noreply,
   socket
   |> assign(:record_set, updated_set)
   |> put_toast(:info, gettext("Set emptied"))}
end

4. Add tests

File: test/music_library/record_sets_test.exs

Add a new describe "empty_record_set/1" block with two tests:

describe "empty_record_set/1" do
  test "removes all items and returns the empty set" do
    {set, [_r1, _r2, r3]} = record_set_with_records(3)

    {:ok, updated} = RecordSets.empty_record_set(set)
    assert updated.items == []
    # Set metadata preserved
    assert updated.name == set.name
    assert updated.description == set.description
    # Items are actually deleted from DB
    assert [] =
             from(i in RecordSetItem, where: i.record_set_id == ^set.id)
             |> Repo.all()
  end

  test "is a no-op on already-empty sets" do
    set = record_set()
    assert set.items == []

    {:ok, updated} = RecordSets.empty_record_set(set)
    assert updated.items == []
  end
end

No LiveView tests are planned. The project does not currently have LiveView test files for RecordSetLive.Index or RecordSetLive.Show. UI acceptance criteria (#1–#4 from the acceptance criteria list) will be verified manually using the steps below. The context-level tests above cover acceptance criterion #5.

Verification

Step	Verification
1. Context function	Run mix test test/music_library/record_sets_test.exs — both tests pass
2. Edge case: already-empty set	Run mix test test/music_library/record_sets_test.exs:NNN (line of the no-op test)
3. Index UI	Manual: open record sets index, click dropdown → Empty, confirm prompt appears, confirm → card updates to show 0/0 records
4. Show UI	Manual: open a set show page, click dropdown → Empty, confirm prompt appears, confirm → grid clears, toast "Set emptied" appears
5. Set preserved	After emptying, verify set name and description are still visible on both index card and show page
6. Full test suite	Run mix test — all existing tests still pass

Definition of Done

• #1 RecordSets.empty_record_set/1 added and tested
• #2 "Empty" dropdown button present in both index and show views
• #3 Confirmation prompt shown before emptying
• #4 Set metadata preserved after emptying
• #5 All existing tests still pass