Change return value of SyncChaptersWithSource.await() (#7715)

* Change return value of `SyncChaptersWithSource.await()`

`updatedToAdd.subtract(reAdded).toList()` never worked as at this point `updatedToAdd` contained ids from db where `reAdded` had default one. Was the same case before the rewrite.

Removed `toDelete` from return value as it was not being used anywhere

* Add doc string

* Use HashSet

Co-authored-by: stevenyomi <95685115+stevenyomi@users.noreply.github.com>

Co-authored-by: stevenyomi <95685115+stevenyomi@users.noreply.github.com>
(cherry picked from commit 11f640cfee427b8912cdc43fc3efc61e0f774aa7)

# Conflicts:
#	app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

app/src/main/java/eu/kanade/domain/chapter/interactor/SyncChaptersWithSource.kt

@@ -29,11 +29,19 @@ class SyncChaptersWithSource(
     private val getChapterByMangaId: GetChapterByMangaId = Injekt.get(),
 ) {
 
+    /**
+     * Method to synchronize db chapters with source ones
+     *
+     * @param rawSourceChapters the chapters from the source.
+     * @param manga the manga the chapters belong to.
+     * @param source the source the manga belongs to.
+     * @return Newly added chapters
+     */
     suspend fun await(
         rawSourceChapters: List<SChapter>,
         manga: Manga,
         source: Source,
-    ): Pair<List<Chapter>, List<Chapter>> {
+    ): List<Chapter> {
         if (rawSourceChapters.isEmpty() && source.id != LocalSource.ID) {
             throw NoChaptersException()
         }
@@ -115,7 +123,7 @@ class SyncChaptersWithSource(
 
         // Return if there's nothing to add, delete or change, avoiding unnecessary db transactions.
         if (toAdd.isEmpty() && toDelete.isEmpty() && toChange.isEmpty()) {
-            return Pair(emptyList(), emptyList())
+            return emptyList()
         }
 
         val reAdded = mutableListOf<Chapter>()
@@ -191,7 +199,8 @@ class SyncChaptersWithSource(
         // Note that last_update actually represents last time the chapter list changed at all
         updateManga.awaitUpdateLastUpdate(manga.id)
 
-        @Suppress("ConvertArgumentToSet") // See tachiyomiorg/tachiyomi#6372.
+        val reAddedUrls = reAdded.map { it.url }.toHashSet()
-        return Pair(updatedToAdd.subtract(reAdded).toList(), toDelete.subtract(reAdded).toList())
+
+        return updatedToAdd.filterNot { it.url in reAddedUrls }
     }
 }

app/src/main/java/eu/kanade/tachiyomi/data/library/LibraryUpdateService.kt

@@ -438,7 +438,7 @@ class LibraryUpdateService(
                                             else -> {
                                                 // Convert to the manga that contains new chapters
                                                 mangaWithNotif.toDomainManga()?.let { domainManga ->
-                                                    val (newChapters, _) = updateManga(domainManga, loggedServices)
+                                                    val newChapters = updateManga(domainManga, loggedServices)
                                                     val newDbChapters = newChapters.map { it.toDbChapter() }
 
                                                     if (newChapters.isNotEmpty()) {
@@ -532,7 +532,7 @@ class LibraryUpdateService(
      * @param manga the manga to update.
      * @return a pair of the inserted and removed chapters.
      */
-    private suspend fun updateManga(manga: DomainManga, loggedServices: List<TrackService>): Pair<List<DomainChapter>, List<DomainChapter>> {
+    private suspend fun updateManga(manga: DomainManga, loggedServices: List<TrackService>): List<DomainChapter> {
         val source = sourceManager.getOrStub(manga.source)
 
         val mangaInfo: MangaInfo = manga.toMangaInfo()
@@ -567,7 +567,7 @@ class LibraryUpdateService(
 
         // Get manga from database to account for if it was removed during the update
         val dbManga = getManga.await(manga.id)
-            ?: return Pair(emptyList(), emptyList())
+            ?: return emptyList()
 
         // [dbmanga] was used so that manga data doesn't get overwritten
         // in case manga gets new chapter

app/src/main/java/eu/kanade/tachiyomi/source/online/all/MergedSource.kt

@@ -163,7 +163,7 @@ class MergedSource : HttpSource() {
         }
     }
 
-    suspend fun fetchChaptersAndSync(manga: Manga, downloadChapters: Boolean = true): Pair<List<Chapter>, List<Chapter>> {
+    suspend fun fetchChaptersAndSync(manga: Manga, downloadChapters: Boolean = true): List<Chapter> {
         val syncChaptersWithSource = Injekt.get<SyncChaptersWithSource>()
         val mangaReferences = getMergedReferencesById.await(manga.id)
         if (mangaReferences.isEmpty()) {
@@ -180,7 +180,7 @@ class MergedSource : HttpSource() {
                 .map { (_, values) ->
                     async {
                         semaphore.withPermit {
-                            values.map {
+                            values.flatMap {
                                 try {
                                     val (source, loadedManga, reference) =
                                         it.load(sourceManager, getManga, insertManga, updateManga)
@@ -192,17 +192,17 @@ class MergedSource : HttpSource() {
                                         if (ifDownloadNewChapters && reference.downloadChapters) {
                                             downloadManager.downloadChapters(
                                                 loadedManga,
-                                                results.first.map(Chapter::toDbChapter),
+                                                results.map(Chapter::toDbChapter),
                                             )
                                         }
                                         results
                                     } else {
-                                        null
+                                        emptyList()
                                     }
                                 } catch (e: Exception) {
                                     if (e is CancellationException) throw e
                                     exception = e
-                                    null
+                                    emptyList()
                                 }
                             }
                         }
@@ -210,9 +210,6 @@ class MergedSource : HttpSource() {
                 }
                 .awaitAll()
                 .flatten()
-                .let { pairs ->
-                    pairs.flatMap { it?.first.orEmpty() } to pairs.flatMap { it?.second.orEmpty() }
-                }
         }.also {
             exception?.let { throw it }
         }

app/src/main/java/eu/kanade/tachiyomi/ui/manga/MangaPresenter.kt

@@ -967,7 +967,7 @@ class MangaPresenter(
                         val chapters = successState.source.getChapterList(successState.manga.toMangaInfo())
                             .map { it.toSChapter() }
 
-                        val (newChapters, _) = syncChaptersWithSource.await(
+                        val newChapters = syncChaptersWithSource.await(
                             chapters,
                             successState.manga,
                             successState.source,

app/src/main/java/exh/eh/EHentaiUpdateWorker.kt

@@ -209,7 +209,7 @@ class EHentaiUpdateWorker(private val context: Context, workerParams: WorkerPara
             val newChapters = source.getChapterList(manga.toMangaInfo())
                 .map { it.toSChapter() }
 
-            val (new, _) = syncChaptersWithSource.await(newChapters, manga, source)
+            val new = syncChaptersWithSource.await(newChapters, manga, source)
             return new to getChapterByMangaId.await(manga.id)
         } catch (t: Throwable) {
             if (t is EHentai.GalleryNotFoundException) {