From b0ea8acce4cc2e6444c42f6e8359377b1aca0f61 Mon Sep 17 00:00:00 2001
From: Ralf Kistner <ralf@journeyapps.com>
Date: Fri, 29 Dec 2023 14:09:39 +0200
Subject: [PATCH 1/2] Add failing test.

---
 .../powersync/test/bucket_storage_test.dart   | 113 ++++++++++++++++++
 1 file changed, 113 insertions(+)

diff --git a/packages/powersync/test/bucket_storage_test.dart b/packages/powersync/test/bucket_storage_test.dart
index 8d4f6e79..aad21265 100644
--- a/packages/powersync/test/bucket_storage_test.dart
+++ b/packages/powersync/test/bucket_storage_test.dart
@@ -674,5 +674,118 @@ void main() {
             {'description': 'server updated'}
           ]));
     });
+
+    test('should revert a failing update', () async {
+      await bucketStorage.saveSyncData(SyncDataBatch([
+        SyncBucketData(
+          bucket: 'bucket1',
+          data: [putAsset1_1, putAsset2_2, putAsset1_3],
+        ),
+      ]));
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '3',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      // Local save
+      db.execute('INSERT INTO assets(id, description) VALUES(?, ?)',
+          ['O3', 'inserted']);
+      final batch = bucketStorage.getCrudBatch();
+      await batch!.complete();
+      await bucketStorage.updateLocalTarget(() async {
+        return '4';
+      });
+
+      expect(
+          db.select('SELECT description FROM assets WHERE id = \'O3\''),
+          equals([
+            {'description': 'inserted'}
+          ]));
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '4',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      expect(db.select('SELECT description FROM assets WHERE id = \'O3\''),
+          equals([]));
+    });
+
+    test('should revert a failing delete', () async {
+      await bucketStorage.saveSyncData(SyncDataBatch([
+        SyncBucketData(
+          bucket: 'bucket1',
+          data: [putAsset1_1, putAsset2_2, putAsset1_3],
+        ),
+      ]));
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '3',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      // Local save
+      db.execute('DELETE FROM assets WHERE id = ?', ['O2']);
+
+      expect(db.select('SELECT description FROM assets WHERE id = \'O2\''),
+          equals([]));
+      // Simulate a permissions error when uploading - data should be preserved.
+      final batch = bucketStorage.getCrudBatch();
+      await batch!.complete();
+
+      await bucketStorage.updateLocalTarget(() async {
+        return '4';
+      });
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '4',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      expect(
+          db.select('SELECT description FROM assets WHERE id = \'O2\''),
+          equals([
+            {'description': 'bar'}
+          ]));
+    });
+
+    test('should revert a failing insert', () async {
+      await bucketStorage.saveSyncData(SyncDataBatch([
+        SyncBucketData(
+          bucket: 'bucket1',
+          data: [putAsset1_1, putAsset2_2, putAsset1_3],
+        ),
+      ]));
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '3',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      // Local save
+      db.execute('DELETE FROM assets WHERE id = ?', ['O2']);
+
+      expect(db.select('SELECT description FROM assets WHERE id = \'O2\''),
+          equals([]));
+      // Simulate a permissions error when uploading - data should be preserved.
+      final batch = bucketStorage.getCrudBatch();
+      await batch!.complete();
+
+      await bucketStorage.updateLocalTarget(() async {
+        return '4';
+      });
+
+      await syncLocalChecked(Checkpoint(
+          lastOpId: '3',
+          writeCheckpoint: '4',
+          checksums: [BucketChecksum(bucket: 'bucket1', checksum: 6)]));
+
+      expect(
+          db.select('SELECT description FROM assets WHERE id = \'O2\''),
+          equals([
+            {'description': 'bar'}
+          ]));
+    });
   });
 }

From 71613af90fb52ed423abe1a4b9d60124b58beb8d Mon Sep 17 00:00:00 2001
From: Ralf Kistner <ralf@journeyapps.com>
Date: Fri, 29 Dec 2023 14:13:16 +0200
Subject: [PATCH 2/2] Fix reverting deletes.

---
 packages/powersync/lib/src/schema_logic.dart | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/packages/powersync/lib/src/schema_logic.dart b/packages/powersync/lib/src/schema_logic.dart
index d8b9b8b0..af4a4d4d 100644
--- a/packages/powersync/lib/src/schema_logic.dart
+++ b/packages/powersync/lib/src/schema_logic.dart
@@ -53,6 +53,15 @@ FOR EACH ROW
 BEGIN
   DELETE FROM $internalNameE WHERE id = OLD.id;
   INSERT INTO ps_crud(tx_id, data) SELECT current_tx, json_object('op', 'DELETE', 'type', ${quoteString(type)}, 'id', OLD.id) FROM ps_tx WHERE id = 1;
+  INSERT INTO ps_oplog(bucket, op_id, op, row_type, row_id, hash, superseded)
+    SELECT '\$local',
+           1,
+           'REMOVE',
+           ${quoteString(type)},
+           OLD.id,
+           0,
+           0;
+  INSERT OR REPLACE INTO ps_buckets(name, pending_delete, last_op, target_op) VALUES('\$local', 1, 0, $maxOpId);
 END""",
     """
 CREATE TRIGGER ${quoteIdentifier('ps_view_insert_$viewName')}