n8n - 💡(How to fix) Fix Destination node not found" error caused by ghost connection remaining in JSON after node deletion [1 comments, 2 participants]

When executing a workflow, a node failed with the error Problem in node '[Node Name]': Destination node not found. Upon inspecting the workflow's underlying JSON, the output connections for the failing node still contained a reference to a previously deleted node (in my case, a Wait node named "30sec"). The node had been deleted from the visual canvas, but the connection data was left behind in the JSON structure. Because the engine was trying to pass data to a node that no longer existed, it threw the error and triggered my error-handling route. 5. The execution fails at Node A with the "Destination node not found" error because the JSON still thinks it needs to route to Node B.

TL;DR

Manually removing and redrawing the connection between nodes can resolve the "Destination node not found" error caused by ghost connections in the workflow JSON.

Guidance

• When deleting a node, verify that all connections to and from the node are also removed from the workflow JSON to prevent ghost connections.
• If a ghost connection is suspected, try deleting and redrawing the affected connections to force the canvas to update the JSON structure.
• Inspect the workflow JSON for any references to deleted nodes, such as the example provided, to identify potential ghost connections.
• Consider implementing a validation check after node deletion to ensure all connections are properly updated in the JSON.

Example

The provided JSON snippet shows a ghost connection:

"Jp Request NoteBook": {
  "main": [
    [
      {
        "node": "30sec", 
        "type": "main",
        "index": 0
      },
      {
        "node": "Eng Request NoteBook",
        "type": "main",
        "index": 0
      }
    ]
  ]
}

This should be updated to remove the reference to the deleted node "30sec".

Notes

This issue appears to be related to a UI state bug, and the provided workaround may not always be effective. Further investigation into the root cause of the bug may be necessary to implement a more robust solution.

Recommendation

Apply the workaround of manually removing and redrawing connections to resolve the issue, as the root cause of the UI state bug is not clear and a fixed version is not implied.