What causes "Node ${detail.id} not found" in windmill-labs/windmill?

Reload the flow/schema map so node ids match the current flow, then retry the mock update

Node ${detail.id} not found

Error message

Node ${detail.id} not found

What it means

In FlowModuleSchemaMap.svelte, the onUpdateMock handler receives an id from the map UI and looks up the corresponding flow module via findModuleById. If no module with that id exists in the flow, it throws 'Node ${id} not found'. This guards against stale or foreign node ids being applied to the flow store.

Source

Thrown at frontend/src/lib/components/flows/map/FlowModuleSchemaMap.svelte:937

				clone.id = copyId(original.id, flowStateStore.val, flowStore.val)
				flowStateStore.val[clone.id] = emptyFlowModuleState()

				dfs([clone], (mod) => {
					if (mod.id !== clone.id) {
						const newModId = nextId(flowStateStore.val, flowStore.val)
						mod.id = newModId
						flowStateStore.val[newModId] = emptyFlowModuleState()
					}
				})

				targetModules.splice(targetIndex + 1, 0, clone)
				refreshFlowStateStore(flowStore)
				selectionManager.selectId(clone.id, { openPanel: true })
			}}
			onUpdateMock={(detail) => {
				let module = findModuleById(detail.id)
				if (!module) {
					throw new Error(`Node ${detail.id} not found`)
				}
				module.mock = $state.snapshot(detail.mock)
				refreshFlowStateStore(flowStore)
			}}
			{onTestFlow}
			{isRunning}
			{onCancelTestFlow}
			{onOpenPreview}
			{onHideJobStatus}
			{controlsPosition}
			exitNoteMode={() => (noteMode = false)}
			onNotePositionUpdate={(noteId, position) => {
				// Update note position via NoteEditor context in edit mode
				if (noteEditorContext?.noteEditor) {
					noteEditorContext.noteEditor.updatePosition(noteId, position)
				}
			}}
			multiSelectEnabled

View on GitHub (pinned to e474e8803c)

Solutions

Reload the flow/schema map so node ids match the current flow, then retry the mock update
Verify the module id exists in the current flow (check value.modules in the YAML or the editor)
Avoid editing mocks on a stale tab — refresh before continuing concurrent edits
If it recurs, check for flow version mismatches (unsaved local copy vs server version)

Example fix

// before
onUpdateMock={(detail) => {
  const module = findModuleById(detail.id)
  module.mock = detail.mock
}}
// after
onUpdateMock={(detail) => {
  const module = findModuleById(detail.id)
  if (!module) {
    sendUserToast('Module no longer exists — reloading flow', true)
    return
  }
  module.mock = $state.snapshot(detail.mock)
}}

Defensive patterns

Strategy: try-catch

Validate before calling

const module = findModuleById(detail.id)
if (!module) { console.warn('module gone, reloading flow'); await reloadFlow(); return }

Type guard

function moduleExists(id: string): boolean {
  return flowStore.get().value.modules.some(m => m.id === id)
}

Try / catch

try {
  updateMock(detail)
} catch (e) {
  if (e.message.startsWith('Node ') && e.message.endsWith(' not found')) {
    sendUserToast('Module no longer exists — refresh the flow', true)
    await refreshFlow()
  }
}

Prevention

Refresh the flow after any external modification before editing mocks
Avoid multiple concurrent editors on the same flow
Re-read flow state after save/reload cycles instead of caching module ids
Handle delete events in the UI by clearing stale selections

When it happens

Trigger: Dispatching an update-mock event with a detail.id that no longer exists in the flow — e.g. the module was deleted in another tab/user session, the flow was reloaded and ids changed, or a stale selection was used.

Common situations: Two users editing the same flow concurrently (one deletes a module while another edits its mock); the schema map kept a cached node id across a flow reload; ids differ between draft and saved flow versions.

Related errors

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/5f4e0d894dc8e38f. Report an issue: GitHub.