fix: invalid null comparison while inserting flow node (#4815)

backend/.sqlx/query-dc32e9e81eab9cda88875020acc414271b96d251bcf54c153c45370d917eea9d.json

@@ -0,0 +1,27 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "\n        WITH existing AS (\n            SELECT id FROM flow_node\n            WHERE hash = $1 AND path = $2 AND workspace_id = $3\n                AND (code IS NOT DISTINCT FROM $4)\n                AND (lock IS NOT DISTINCT FROM $5)\n                AND (flow IS NOT DISTINCT FROM $6)\n            LIMIT 1\n        ),\n        inserted AS (\n            INSERT INTO flow_node (hash, path, workspace_id, code, lock, flow)\n            VALUES ($1, $2, $3, $4, $5, $6)\n            ON CONFLICT DO NOTHING\n            RETURNING id\n        )\n        SELECT id FROM existing\n        UNION ALL\n        SELECT id FROM inserted\n        ",
+  "describe": {
+    "columns": [
+      {
+        "ordinal": 0,
+        "name": "id",
+        "type_info": "Int8"
+      }
+    ],
+    "parameters": {
+      "Left": [
+        "Int8",
+        "Text",
+        "Text",
+        "Text",
+        "Text",
+        "Jsonb"
+      ]
+    },
+    "nullable": [
+      null
+    ]
+  },
+  "hash": "dc32e9e81eab9cda88875020acc414271b96d251bcf54c153c45370d917eea9d"
+}

backend/windmill-worker/src/worker_lockfiles.rs

@@ -1023,7 +1023,10 @@ async fn insert_flow_node<'c>(
         r#"
         WITH existing AS (
             SELECT id FROM flow_node
-            WHERE hash = $1 AND path = $2 AND workspace_id = $3 AND code = $4 AND lock = $5 AND (flow IS NOT DISTINCT FROM $6)
+            WHERE hash = $1 AND path = $2 AND workspace_id = $3
+                AND (code IS NOT DISTINCT FROM $4)
+                AND (lock IS NOT DISTINCT FROM $5)
+                AND (flow IS NOT DISTINCT FROM $6)
             LIMIT 1
         ),
         inserted AS (