feat(web): copy source tracks when duplicating a playlist

Promotes the duplicate-playlist flow from metadata-only to a true
duplicate that also copies every track from the source.

- New DUPLICATE_PLAYLIST action carries the source playlist id, the
  composed form fields, the full source track id list, and an isAlbum
  flag.
- New duplicatePlaylistSaga drives the full sequence: it dispatches the
  existing createPlaylist / createAlbum saga with the first source
  track as initTrackId, takes() the resulting CREATE_PLAYLIST_REQUESTED
  to learn the new playlist id, then sequentially dispatches
  addTrackToPlaylist({ silent: true }) for every remaining track with
  a small inter-dispatch delay so each saga sees the previous
  optimistic update. Closes with a single summary toast.
- DuplicatePlaylistModal now dispatches DUPLICATE_PLAYLIST and exposes
  the actual track count to the user ("All N tracks will be copied")
  instead of the previous "tracks not copied" note.

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

Author: dylanjeffers

packages/common/src/store/cache/collections/actions.ts

@@ -24,6 +24,8 @@ export const ORDER_PLAYLIST_FAILED = 'ORDER_PLAYLIST_FAILED'
 export const PUBLISH_PLAYLIST = 'PUBLISH_PLAYLIST'
 export const PUBLISH_PLAYLIST_FAILED = 'PUBLISH_PLAYLIST_FAILED'
 
+export const DUPLICATE_PLAYLIST = 'DUPLICATE_PLAYLIST'
+
 /**
  * @param initTrackId optional track id to pull artwork from.
  */
@@ -175,3 +177,26 @@ export function publishPlaylistFailed(
 ) {
   return { type: PUBLISH_PLAYLIST_FAILED, error, params, metadata }
 }
+
+export function duplicatePlaylist({
+  sourcePlaylistId,
+  formFields,
+  trackIds,
+  source,
+  isAlbum
+}: {
+  sourcePlaylistId: ID
+  formFields: Partial<Collection>
+  trackIds: ID[]
+  source: string
+  isAlbum?: boolean
+}) {
+  return {
+    type: DUPLICATE_PLAYLIST,
+    sourcePlaylistId,
+    formFields,
+    trackIds,
+    source,
+    isAlbum: !!isAlbum
+  }
+}

packages/web/src/common/store/cache/collections/duplicatePlaylistSaga.ts

@@ -0,0 +1,65 @@
+import { cacheCollectionsActions, toastActions } from '@audius/common/store'
+import { call, delay, put, take, takeEvery } from 'typed-redux-saga'
+
+const { toast } = toastActions
+
+const INTER_DISPATCH_DELAY_MS = 30
+
+const messages = {
+  duplicated: (count: number, isAlbum: boolean) =>
+    `Duplicated ${isAlbum ? 'album' : 'playlist'} with ${count} ${
+      count === 1 ? 'track' : 'tracks'
+    }`,
+  duplicatedNoTracks: (isAlbum: boolean) =>
+    `Duplicated ${isAlbum ? 'album' : 'playlist'}`
+}
+
+export function* duplicatePlaylistSaga() {
+  yield* takeEvery(
+    cacheCollectionsActions.DUPLICATE_PLAYLIST,
+    duplicatePlaylistWorker
+  )
+}
+
+function* duplicatePlaylistWorker(
+  action: ReturnType<typeof cacheCollectionsActions.duplicatePlaylist>
+) {
+  const { formFields, trackIds, source, isAlbum } = action
+  const initTrackId = trackIds.length > 0 ? trackIds[0] : null
+
+  const createAction = isAlbum
+    ? cacheCollectionsActions.createAlbum
+    : cacheCollectionsActions.createPlaylist
+
+  yield* put(createAction(formFields, source, initTrackId, 'route'))
+
+  if (trackIds.length <= 1) {
+    if (trackIds.length === 0) {
+      yield* put(toast({ content: messages.duplicatedNoTracks(isAlbum) }))
+    } else {
+      yield* put(toast({ content: messages.duplicated(1, isAlbum) }))
+    }
+    return
+  }
+
+  const requestedAction = yield* take(
+    cacheCollectionsActions.CREATE_PLAYLIST_REQUESTED
+  )
+  const newPlaylistId = (requestedAction as unknown as { playlistId: number })
+    .playlistId
+
+  for (let i = 1; i < trackIds.length; i += 1) {
+    yield* put(
+      cacheCollectionsActions.addTrackToPlaylist(trackIds[i], newPlaylistId, {
+        silent: true
+      })
+    )
+    yield* delay(INTER_DISPATCH_DELAY_MS)
+  }
+
+  yield* call(function* () {
+    yield* put(
+      toast({ content: messages.duplicated(trackIds.length, isAlbum) })
+    )
+  })
+}

packages/web/src/common/store/cache/collections/webSagas.ts

@@ -1,6 +1,7 @@
 import commonSagas from './commonSagas'
 import { createPlaylistRequestedSaga } from './createPlaylistRequestedSaga'
+import { duplicatePlaylistSaga } from './duplicatePlaylistSaga'
 
 export default function sagas() {
-  return [...commonSagas(), createPlaylistRequestedSaga]
+  return [...commonSagas(), createPlaylistRequestedSaga, duplicatePlaylistSaga]
 }

packages/web/src/components/duplicate-playlist-modal/DuplicatePlaylistModal.tsx

@@ -28,7 +28,7 @@ import UploadArtwork from 'components/upload/UploadArtwork'
 import { useCollectionCoverArt } from 'hooks/useCollectionCoverArt'
 import { resizeImage } from 'utils/imageProcessingUtil'
 
-const { createPlaylist, createAlbum } = cacheCollectionsActions
+const { duplicatePlaylist } = cacheCollectionsActions
 
 const messages = {
   title: 'Duplicate Playlist',
@@ -53,8 +53,10 @@ const messages = {
   newDescriptionPlaceholder: 'Describe what makes this special',
   cancel: 'Cancel',
   duplicate: 'Duplicate',
-  trackCopyNote:
-    'Tracks are not copied automatically — you can add them after duplicating.',
+  trackCopyNote: (count: number) =>
+    count === 0
+      ? 'No tracks to copy from this playlist.'
+      : `All ${count} ${count === 1 ? 'track' : 'tracks'} will be copied to the new playlist.`,
   copySuffix: ' (Copy)'
 }
 
@@ -179,8 +181,18 @@ export const DuplicatePlaylistModal = () => {
         sourceCollection.is_image_autogenerated ?? false
     }
 
-    const action = isAlbum ? createAlbum : createPlaylist
-    dispatch(action(formFields, CreatePlaylistSource.NAV, undefined, 'route'))
+    const sourceTrackIds =
+      sourceCollection.playlist_contents?.track_ids.map((t) => t.track) ?? []
+
+    dispatch(
+      duplicatePlaylist({
+        sourcePlaylistId: sourceCollection.playlist_id,
+        formFields,
+        trackIds: sourceTrackIds,
+        source: CreatePlaylistSource.NAV,
+        isAlbum
+      })
+    )
     onClose()
   }, [
     customArtwork,
@@ -321,7 +333,9 @@ export const DuplicatePlaylistModal = () => {
                 ) : null}
               </Flex>
               <Text variant='body' size='s' color='subdued'>
-                {messages.trackCopyNote}
+                {messages.trackCopyNote(
+                  sourceCollection.playlist_contents?.track_ids.length ?? 0
+                )}
               </Text>
             </Flex>
           ) : null}