Server: Fix delta API can return changes in wrong order (#14713)

packages/server/src/models/ChangeModel.test.ts

@@ -51,17 +51,17 @@ describe('ChangeModel', () => {
 		expect(allUncompressedChanges.length).toBe(8);
 
 		{
-			// When we get all the changes, we get DELETE 1, CREATE 2, and CREATE 3:
+			// When we get all the changes, we get CREATE 2, DELETE 1, and CREATE 3:
 			// - We don't get CREATE 1 since CREATE 1 -> DELETE 1 was compressed to
 			//   DELETE 1.
 			// - We don't get any UPDATE event since they've been compressed
 			//   down to the CREATE events.
 			const changes = (await changeModel.delta(user.id)).items;
 			expect(changes.length).toBe(3);
-			expect(changes[0].item_id).toBe(item1.id);
-			expect(changes[0].type).toBe(ChangeType.Delete);
-			expect(changes[1].item_id).toBe(item2.id);
-			expect(changes[1].type).toBe(ChangeType.Create);
+			expect(changes[0].item_id).toBe(item2.id);
+			expect(changes[0].type).toBe(ChangeType.Create);
+			expect(changes[1].item_id).toBe(item1.id);
+			expect(changes[1].type).toBe(ChangeType.Delete);
 			expect(changes[2].item_id).toBe(item3.id);
 			expect(changes[2].type).toBe(ChangeType.Create);
 		}

packages/server/src/models/ChangeModel.ts

@@ -282,10 +282,6 @@ export default class ChangeModel extends BaseModel<Change> {
 		// returns the rows directly;
 		const output: Change[] = results.rows ? results.rows : results;
 
-		// This property is present only for the purpose of ordering the results
-		// and can be removed afterwards.
-		for (const change of output) delete change.counter;
-
 		return output;
 	}
 
@@ -324,6 +320,10 @@ export default class ChangeModel extends BaseModel<Change> {
 			return deltaChange;
 		});
 
+		// This property is present only for the purpose of ordering the results
+		// and can be removed afterwards.
+		for (const change of finalChanges) delete change.counter;
+
 		return {
 			items: finalChanges,
 			// If we have changes, we return the ID of the latest changes from which delta sync can resume.