In case when removed rank > 0 deltas, we still had a file diff - unhandled case when filediff exists in DB

Author: MarcelGeo

server/mergin/sync/files.py

@@ -287,7 +287,7 @@ def to_data_delta(self):
             version=self.version,
         )
         if self.diffs:
-            result.diff = self.diffs[0].id
+            result.diff = None
         return result
 
 

server/mergin/sync/models.py

@@ -1359,6 +1359,11 @@ def create_checkpoint(
                     # Patch the delta with the path to the new diff checkpoint
                     item.diff = checkpoint_diff.path
                     db.session.add(checkpoint_diff)
+                else:
+                    # checkpoint already exists, just patch the delta with the path to the existing diff checkpoint
+                    # this could happen when file diff exists but dela was missing
+                    # this allowing us to remove rank > 0 delta checkpoints in case of inconsistencies
+                    item.diff = existing_diff_checkpoint.path
 
         checkpoint_delta = ProjectVersionDelta(
             project_id=project_id,