[bug] TypeError when loading workflows with promoted widgets - _listenerController.abort not a function

[christian-byrne]

Description

When loading a workflow that contains promoted widgets, the following error occurs:

TypeError: input._listenerController?.abort is not a function
    at #addSubgraphInputListeners (SubgraphNode.ts:104:32)
    at ComfyNode._internalConfigureAfterSlots (SubgraphNode.ts:169:12)
    at ComfyNode.configure (LGraphNode.ts:761:10)

Steps to Reproduce

1. Create a subgraph with DOM widgets
2. Connect a DOM widget to a subgraph input (promoting it)
3. Save the workflow
4. Reload the page or load the saved workflow
5. Error occurs during deserialization

Root Cause

The _listenerController property on input slots is not serialized/deserialized. When loading a workflow:

• Input slots are plain objects from JSON
• They don't have _listenerController property
• Code assumes optional chaining (?.) is enough, but abort might not be a function
• This happens in 3 places: #addSubgraphInputListeners, configure, and onRemoved

Expected Behavior

Workflows with promoted widgets should load without errors.

Actual Behavior

TypeError is thrown because the code tries to call abort() on a non-existent or non-AbortController object.

Solution

Add proper type checking before calling abort:

// Instead of:
input._listenerController?.abort()

// Use:
if (input._listenerController && typeof input._listenerController.abort === 'function') {
  input._listenerController.abort()
}

This needs to be fixed in:

1. SubgraphNode.#addSubgraphInputListeners (line 104)
2. SubgraphNode.configure (line 142)
3. SubgraphNode.onRemoved (line 356)

Environment

• litegraph.js version: 0.16.9
• Affects: All browsers
• Severity: High (breaks workflow loading)

[webfiltered]

This can be worked around in the Object.assign of NodeInputSlot. This is still a leak of concrete impl. into serialised objects, which I haven't found yet.

Created an issue to track the removal of the Object.assign workaround.

• Remove Object.assign in node input / output slot classes #1138

[webfiltered]

Direct impact of this issue is resolved by

• Add workaround for incorrect downstream patch #1139

• Fix for root cause requires more work: Fix i18n workaround breaks node configure & subgraphs ComfyUI_frontend#4481