From 7e2118901eb77894ff3f57d35b9a7202462fcb01 Mon Sep 17 00:00:00 2001
From: Santo Shakil <shakil.mezbah@gmail.com>
Date: Mon, 13 Jul 2026 15:44:39 +0600
Subject: [PATCH] fix(mobile): back up files moved into a watched folder on
 android

---
 .../repositories/local_album.repository.dart  | 16 +++--
 .../local_album_repository_test.dart          | 72 +++++++++++++++++++
 2 files changed, 81 insertions(+), 7 deletions(-)

diff --git a/mobile/lib/infrastructure/repositories/local_album.repository.dart b/mobile/lib/infrastructure/repositories/local_album.repository.dart
index 2c80385c34..a443ffb975 100644
--- a/mobile/lib/infrastructure/repositories/local_album.repository.dart
+++ b/mobile/lib/infrastructure/repositories/local_album.repository.dart
@@ -210,17 +210,19 @@ class DriftLocalAlbumRepository extends DriftDatabaseRepository {
       await _deleteAssets(deletes);
 
       await _upsertAssets(updates);
+      // Drop every existing album link for each changed asset before re-adding the
+      // ones the native side reports. A moved asset only reports its new album here,
+      // so leaving the old link around makes the per-album delete sweep wipe the
+      // asset entirely (it is still linked to a bucket it no longer lives in).
+      await _db.batch((batch) async {
+        for (final assetId in assetAlbums.keys) {
+          batch.deleteWhere(_db.localAlbumAssetEntity, (f) => f.assetId.equals(assetId));
+        }
+      });
       // The ugly casting below is required for now because the generated code
       // casts the returned values from the platform during decoding them
       // and iterating over them causes the type to be List<Object?> instead of
       // List<String>
-      await _db.batch((batch) async {
-        assetAlbums.cast<String, List<Object?>>().forEach((assetId, albumIds) {
-          for (final albumId in albumIds.cast<String?>().nonNulls) {
-            batch.deleteWhere(_db.localAlbumAssetEntity, (f) => f.albumId.equals(albumId) & f.assetId.equals(assetId));
-          }
-        });
-      });
       await _db.batch((batch) async {
         assetAlbums.cast<String, List<Object?>>().forEach((assetId, albumIds) {
           batch.insertAll(
diff --git a/mobile/test/infrastructure/repositories/local_album_repository_test.dart b/mobile/test/infrastructure/repositories/local_album_repository_test.dart
index fae0e09171..bd4acca483 100644
--- a/mobile/test/infrastructure/repositories/local_album_repository_test.dart
+++ b/mobile/test/infrastructure/repositories/local_album_repository_test.dart
@@ -2,6 +2,7 @@ import 'package:drift/drift.dart';
 import 'package:drift/native.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:immich_mobile/domain/models/album/local_album.model.dart';
+import 'package:immich_mobile/domain/models/asset/base_asset.model.dart';
 import 'package:immich_mobile/infrastructure/repositories/db.repository.dart';
 import 'package:immich_mobile/infrastructure/repositories/local_album.repository.dart';
 
@@ -35,4 +36,75 @@ void main() {
       expect(albums[3].id, '2'); // excluded
     });
   });
+
+  group('processDelta', () {
+    // Regression for #22844: an asset moved (not copied) into a backup album on
+    // Android was dropped. The delta reports only the asset's new album, and the
+    // stale link to its old album made the per-album delete sweep wipe the asset.
+    test('keeps an asset moved to another album that still holds other assets', () async {
+      final localAlbumRepo = mediumFactory.getRepository<DriftLocalAlbumRepository>();
+
+      final moved = _localAsset('moved');
+      final other = _localAsset('other');
+      await localAlbumRepo.upsert(
+        mediumFactory.localAlbum(id: 'src', backupSelection: BackupSelection.none),
+        toUpsert: [moved, other],
+      );
+      final anchor = _localAsset('anchor');
+      await localAlbumRepo.upsert(
+        mediumFactory.localAlbum(id: 'dst', backupSelection: BackupSelection.selected),
+        toUpsert: [anchor],
+      );
+
+      // Delta reports the moved asset now living only in the destination album.
+      await localAlbumRepo.processDelta(
+        updates: [moved],
+        deletes: [],
+        assetAlbums: {
+          'moved': ['dst'],
+        },
+      );
+
+      // Per-album delete sweep, as sync() runs on Android. src now physically
+      // holds only `other`; dst holds `anchor` and the moved asset.
+      await localAlbumRepo.syncDeletes('src', ['other']);
+      await localAlbumRepo.syncDeletes('dst', ['anchor', 'moved']);
+
+      final dstIds = (await localAlbumRepo.getAssets('dst')).map((a) => a.id).toSet();
+      final srcIds = await localAlbumRepo.getAssetIds('src');
+
+      expect(dstIds, contains('moved')); // survived and linked to the backed-up album
+      expect(srcIds, isNot(contains('moved'))); // stale source link cleared
+      expect(srcIds, contains('other')); // untouched asset stays put
+    });
+
+    test('replaces album membership with exactly what the delta reports', () async {
+      final localAlbumRepo = mediumFactory.getRepository<DriftLocalAlbumRepository>();
+
+      final moved = _localAsset('moved');
+      await localAlbumRepo.upsert(mediumFactory.localAlbum(id: 'src'), toUpsert: [moved]);
+      await localAlbumRepo.upsert(mediumFactory.localAlbum(id: 'dst'));
+
+      await localAlbumRepo.processDelta(
+        updates: [moved],
+        deletes: [],
+        assetAlbums: {
+          'moved': ['dst'],
+        },
+      );
+
+      expect(await localAlbumRepo.getAssetIds('src'), isEmpty);
+      expect(await localAlbumRepo.getAssetIds('dst'), ['moved']);
+    });
+  });
 }
+
+LocalAsset _localAsset(String id) => LocalAsset(
+  id: id,
+  name: '$id.jpg',
+  type: AssetType.image,
+  createdAt: DateTime(2024),
+  updatedAt: DateTime(2024),
+  playbackStyle: AssetPlaybackStyle.image,
+  isEdited: false,
+);