Apply the write checkpoint after draining the CRUD queue

powersync/src/db/internal.rs

@@ -112,7 +112,7 @@ impl InnerPowerSyncState {
         if let Some(write_checkpoint) = write_checkpoint {
             // If there are no remaining crud items we can set the target op to the checkpoint.
             let stmt = writer.inner.prepare("SELECT 1 FROM ps_crud LIMIT 1")?;
-            if let ResultCode::OK = stmt.step()? {
+            if let ResultCode::DONE = stmt.step()? {
                 target_op = write_checkpoint;
             }
         }

powersync/tests/crud_test.rs

@@ -222,6 +222,36 @@ fn insert() {
     });
 }
 
+#[test]
+fn applies_checkpoint_after_draining_crud_queue() {
+    future::block_on(async move {
+        let test = DatabaseTest::new();
+        let db = test.in_memory_database();
+
+        execute(
+            &db,
+            "INSERT INTO users (id, name) VALUES (?, ?)",
+            params!["test", "name"],
+        )
+        .await;
+
+        let transaction = db.next_crud_transaction().await.unwrap().unwrap();
+        transaction.complete_with_checkpoint(42).await.unwrap();
+
+        let mut reader = db.reader().await.unwrap();
+        let reader = reader.transaction().unwrap();
+        let checkpoint: i64 = reader
+            .query_one(
+                "SELECT powersync_control('target_checkpoint_request_id', NULL)",
+                params![],
+                |row| row.get(0),
+            )
+            .unwrap();
+
+        assert_eq!(checkpoint, 42);
+    });
+}
+
 #[test]
 fn crud_transactions() {
     async fn create_transaction(db: &PowerSyncDatabase, amount: usize) {