Fix download chapter dir when scanlator is empty or changed (#7780)

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

@@ -103,8 +103,13 @@ class SyncChaptersWithSource(
                 toAdd.add(toAddChapter)
             } else {
                 if (shouldUpdateDbChapter.await(dbChapter, chapter)) {
-                    if (dbChapter.name != chapter.name && downloadManager.isChapterDownloaded(dbChapter.name, dbChapter.scanlator, manga.title, manga.source)) {
-                        downloadManager.renameChapter(source, manga, dbChapter.toDbChapter(), chapter.toDbChapter())
+                    downloadManager.run {
+                        val shouldRenameChapter = provider.isChapterDirNameChanged(dbChapter, chapter) &&
+                            isChapterDownloaded(dbChapter.name, dbChapter.scanlator, manga.title, manga.source)
+
+                        if (shouldRenameChapter) {
+                            renameChapter(source, manga, dbChapter.toDbChapter(), chapter.toDbChapter())
+                        }
                     }
                     var toChangeChapter = dbChapter.copy(
                         name = chapter.name,

app/src/main/java/eu/kanade/domain/chapter/model/Chapter.kt

@@ -37,7 +37,7 @@ data class Chapter(
             url = sChapter.url,
             dateUpload = sChapter.date_upload,
             chapterNumber = sChapter.chapter_number,
-            scanlator = sChapter.scanlator,
+            scanlator = sChapter.scanlator?.ifBlank { null },
         )
     }
 

app/src/main/java/eu/kanade/tachiyomi/data/download/DownloadProvider.kt

@@ -15,6 +15,7 @@ import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.onEach
 import logcat.LogPriority
 import uy.kohesive.injekt.injectLazy
+import eu.kanade.domain.chapter.model.Chapter as DomainChapter
 
 /**
  * This class is used to provide the directories where the downloads should be saved.
@@ -144,6 +145,10 @@ class DownloadProvider(private val context: Context) {
         )
     }
 
+    fun isChapterDirNameChanged(oldChapter: DomainChapter, newChapter: DomainChapter): Boolean {
+        return oldChapter.name != newChapter.name || oldChapter.scanlator != newChapter.scanlator
+    }
+
     /**
      * Returns valid downloaded chapter directory names.
      *
@@ -152,15 +157,21 @@ class DownloadProvider(private val context: Context) {
      */
     fun getValidChapterDirNames(chapterName: String, chapterScanlator: String?): List<String> {
         val chapterDirName = getChapterDirName(chapterName, chapterScanlator)
-        return listOf(
+        return buildList(5) {
             // Folder of images
-            chapterDirName,
+            add(chapterDirName)
 
             // Archived chapters
-            "$chapterDirName.cbz",
+            add("$chapterDirName.cbz")
+
+            if (chapterScanlator == null) {
+                // Previously null scanlator fields were converted to "" due to a bug
+                add("_$chapterDirName")
+                add("_$chapterDirName.cbz")
+            }
 
             // Legacy chapter directory name used in v0.9.2 and before
-            DiskUtil.buildValidFilename(chapterName),
-        )
+            add(DiskUtil.buildValidFilename(chapterName))
+        }
     }
 }