refactor(subgraph): consolidate type guards and tighten review nits

- Extract canonical isWidgetValue helper to types/widgets.ts and dedupe
  copies in promotedWidgetView, promotionUtils, and SubgraphNode
- Replace cast in proxyWidgetMigration.pickHostValue with isWidgetValue
  narrowing; treat invalid host payloads as holes
- Replace 'getSlotFromWidget' duck-type guard in promoteWidget with
  instanceof LGraphNode narrowing
- Add DEV-only console.warn in SubgraphNode.serialize() when host widgets
  contain non-promoted entries (per ADR 0009)
- Extract LGraphTriggerActions tuple as single source of truth for the
  runtime Set and the LGraphTriggerAction type union
- Replace in-place tuple slot mutation in appModeStore.updateInputConfig
  with splice replacing the whole entry
- Drop dead setter on activeWidgets computed in SubgraphEditor.vue

Amp-Thread-ID: https://ampcode.com/threads/T-019e2812-d683-710e-946f-9ddb9018ff5a
Co-authored-by: Amp <amp@ampcode.com>

src/components/rightSidePanel/subgraph/SubgraphEditor.vue

@@ -41,16 +41,10 @@ const activeNode = computed(() => {
   return undefined
 })
 
-const activeWidgets = computed<WidgetItem[]>({
-  get() {
-    const node = activeNode.value
-    if (!node) return []
-
-    return [...getActivePromotedWidgets(node), ...getActivePreviewWidgets(node)]
-  },
-  set(value: WidgetItem[]) {
-    updateActiveWidgets(value, activeWidgets.value)
-  }
+const activeWidgets = computed<WidgetItem[]>(() => {
+  const node = activeNode.value
+  if (!node) return []
+  return [...getActivePromotedWidgets(node), ...getActivePreviewWidgets(node)]
 })
 
 const activePromotedWidgets = computed<WidgetItem[]>({

src/core/graph/subgraph/migration/proxyWidgetMigration.ts

@@ -24,6 +24,7 @@ import type {
   IBaseWidget,
   TWidgetValue
 } from '@/lib/litegraph/src/types/widgets'
+import { isWidgetValue } from '@/lib/litegraph/src/types/widgets'
 import { usePreviewExposureStore } from '@/stores/previewExposureStore'
 
 /**
@@ -206,7 +207,12 @@ function pickHostValue(
   ) {
     return { value: undefined, isHole: true }
   }
-  return { value: hostWidgetValues[index] as TWidgetValue, isHole: false }
+  // Narrow rather than cast: a slot whose payload isn't a `TWidgetValue`
+  // (e.g. a function or `null` from corrupted serialization) is treated as
+  // a hole so the migration falls back to seeding from the source widget.
+  const raw = hostWidgetValues[index]
+  if (!isWidgetValue(raw)) return { value: undefined, isHole: true }
+  return { value: raw, isHole: false }
 }
 
 function findHostInputForLinkedSource(

src/core/graph/subgraph/promotedWidgetView.ts

@@ -4,6 +4,7 @@ import type { CanvasPointer } from '@/lib/litegraph/src/CanvasPointer'
 import type { Point } from '@/lib/litegraph/src/interfaces'
 import type { CanvasPointerEvent } from '@/lib/litegraph/src/types/events'
 import type { IBaseWidget } from '@/lib/litegraph/src/types/widgets'
+import { isWidgetValue } from '@/lib/litegraph/src/types/widgets'
 import type { SubgraphNode } from '@/lib/litegraph/src/subgraph/SubgraphNode'
 import type { BaseWidget } from '@/lib/litegraph/src/widgets/BaseWidget'
 import { toConcreteWidget } from '@/lib/litegraph/src/widgets/widgetMap'
@@ -37,14 +38,6 @@ interface SubgraphSlotRef {
   displayName?: string
 }
 
-function isWidgetValue(value: unknown): value is IBaseWidget['value'] {
-  if (value === undefined) return true
-  if (typeof value === 'string') return true
-  if (typeof value === 'number') return true
-  if (typeof value === 'boolean') return true
-  return value !== null && typeof value === 'object'
-}
-
 function isValueControlWidget(widget: IBaseWidget): boolean {
   return (
     (widget as Record<symbol, unknown>)[IS_CONTROL_WIDGET] === true &&

src/core/graph/subgraph/promotionUtils.ts

@@ -2,12 +2,11 @@ import * as Sentry from '@sentry/vue'
 import type { PromotedWidgetSource } from '@/core/graph/subgraph/promotedWidgetTypes'
 import { isPromotedWidgetView } from '@/core/graph/subgraph/promotedWidgetTypes'
 import { t } from '@/i18n'
-import type {
-  IContextMenuValue,
-  LGraphNode
-} from '@/lib/litegraph/src/litegraph'
+import type { IContextMenuValue } from '@/lib/litegraph/src/litegraph'
+import { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import type { SubgraphNode } from '@/lib/litegraph/src/subgraph/SubgraphNode'
-import type { IBaseWidget } from '@/lib/litegraph/src/types/widgets.ts'
+import type { IBaseWidget } from '@/lib/litegraph/src/types/widgets'
+import { isWidgetValue } from '@/lib/litegraph/src/types/widgets'
 import { nextUniqueName } from '@/lib/litegraph/src/strings'
 import { useToastStore } from '@/platform/updates/common/toastStore'
 import {
@@ -25,14 +24,6 @@ type PartialNode = Pick<LGraphNode, 'title' | 'id' | 'type'>
 export type WidgetItem = [LGraphNode, IBaseWidget]
 export { CANVAS_IMAGE_PREVIEW_WIDGET }
 
-function isWidgetValue(value: unknown): value is IBaseWidget['value'] {
-  if (value === undefined) return true
-  if (typeof value === 'string') return true
-  if (typeof value === 'number') return true
-  if (typeof value === 'boolean') return true
-  return value !== null && typeof value === 'object'
-}
-
 export function getWidgetName(w: IBaseWidget): string {
   return isPromotedWidgetView(w) ? w.sourceWidgetName : w.name
 }
@@ -335,28 +326,23 @@ export function promoteWidget(
   parents: SubgraphNode[]
 ) {
   const source = toPromotionSource(node, widget)
+  // Both downstream helpers (`promotePreviewViaExposure`,
+  // `promoteValueWidgetViaSubgraphInput`) require the full `LGraphNode`
+  // shape — a `Pick<...>` won't do. Narrow once with `instanceof` rather
+  // than re-checking each call site with property guards + casts.
+  if (!(node instanceof LGraphNode)) return
   for (const parent of parents) {
     if (isPreviewPseudoWidget(widget)) {
-      promotePreviewViaExposure(
-        parent,
-        node as LGraphNode,
-        source.sourceWidgetName
-      )
+      promotePreviewViaExposure(parent, node, source.sourceWidgetName)
       continue
     }
-    if ('getSlotFromWidget' in node) {
-      const result = promoteValueWidgetViaSubgraphInput(
-        parent,
-        node as LGraphNode,
-        widget
-      )
-      if (!result.ok) {
-        Sentry.addBreadcrumb({
-          category: 'subgraph',
-          level: 'warning',
-          message: `Failed to promote widget "${source.sourceWidgetName}" on node ${node.id}: ${result.reason}`
-        })
-      }
+    const result = promoteValueWidgetViaSubgraphInput(parent, node, widget)
+    if (!result.ok) {
+      Sentry.addBreadcrumb({
+        category: 'subgraph',
+        level: 'warning',
+        message: `Failed to promote widget "${source.sourceWidgetName}" on node ${node.id}: ${result.reason}`
+      })
     }
   }
   refreshPromotedWidgetRendering(parents)

src/lib/litegraph/src/LGraph.ts

@@ -76,6 +76,7 @@ import type {
   LGraphTriggerHandler,
   LGraphTriggerParam
 } from './types/graphTriggers'
+import { LGraphTriggerActions } from './types/graphTriggers'
 import type {
   ExportedSubgraph,
   ExposedWidget,
@@ -96,6 +97,9 @@ export type {
   LGraphTriggerParam
 } from './types/graphTriggers'
 
+/** Runtime allowlist for {@link LGraph.trigger}, derived from {@link LGraphTriggerActions}. */
+const validTriggerActions = new Set<LGraphTriggerAction>(LGraphTriggerActions)
+
 export type RendererType = 'LG' | 'Vue' | 'Vue-corrected'
 
 /**
@@ -1362,13 +1366,7 @@ export class LGraph
   ): void
   trigger(action: string, param: unknown): void
   trigger(action: string, param: unknown) {
-    const validEventTypes = new Set<LGraphTriggerAction>([
-      'node:slot-links:changed',
-      'node:slot-errors:changed',
-      'node:property:changed',
-      'node:slot-label:changed'
-    ])
-    if (!validEventTypes.has(action as LGraphTriggerAction)) return
+    if (!validTriggerActions.has(action as LGraphTriggerAction)) return
     if (!param || typeof param !== 'object') return
 
     this.onTrigger?.({ type: action, ...param } as LGraphTriggerEvent)

src/lib/litegraph/src/subgraph/SubgraphNode.ts

@@ -28,10 +28,8 @@ import type {
   ISerialisedNode
 } from '@/lib/litegraph/src/types/serialisation'
 import { NodeSlotType } from '@/lib/litegraph/src/types/globalEnums'
-import type {
-  IBaseWidget,
-  TWidgetValue
-} from '@/lib/litegraph/src/types/widgets'
+import type { IBaseWidget } from '@/lib/litegraph/src/types/widgets'
+import { isWidgetValue } from '@/lib/litegraph/src/types/widgets'
 import {
   createPromotedWidgetView,
   isPromotedWidgetView
@@ -66,14 +64,6 @@ type LinkedPromotionEntry = PromotedWidgetSource & {
 // the SVG's internal stylesheet on every ctx.drawImage() call per frame.
 const workflowBitmapCache = createBitmapCache(workflowSvg, 32)
 
-function isWidgetValue(value: unknown): value is TWidgetValue {
-  if (value === undefined) return true
-  if (typeof value === 'string') return true
-  if (typeof value === 'number') return true
-  if (typeof value === 'boolean') return true
-  return value !== null && typeof value === 'object'
-}
-
 /**
  * An instance of a {@link Subgraph}, displayed as a node on the containing (parent) graph.
  */
@@ -1154,6 +1144,24 @@ export class SubgraphNode extends LGraphNode implements BaseLGraph {
 
     serialized.properties = serializedProperties
 
+    // Per ADR 0009, host SubgraphNodes only carry promoted widgets — non-
+    // promoted host widgets would be silently dropped here. Surface the
+    // unexpected case in dev so a future custom subclass that adds bare
+    // widgets isn't ignored without a trace.
+    if (
+      import.meta.env?.DEV &&
+      this.widgets.some((w) => !isPromotedWidgetView(w))
+    ) {
+      console.warn(
+        `SubgraphNode ${this.id}: serialize() drops non-promoted host widgets ` +
+          `(${this.widgets
+            .filter((w) => !isPromotedWidgetView(w))
+            .map((w) => w.name)
+            .join(', ')}); ` +
+          'expected only PromotedWidgetView instances per ADR 0009.'
+      )
+    }
+
     const widgetValues = this.inputs.flatMap((input) => {
       const widget = input._widget
       if (!widget || !isPromotedWidgetView(widget)) return []

src/lib/litegraph/src/types/graphTriggers.ts

@@ -35,7 +35,20 @@ export type LGraphTriggerEvent =
   | NodeSlotLinksChangedEvent
   | NodeSlotLabelChangedEvent
 
-export type LGraphTriggerAction = LGraphTriggerEvent['type']
+/**
+ * Single source of truth for actions accepted by `LGraph.trigger()`.
+ * Both the runtime allowlist (`LGraphTriggerActions`) and the static type
+ * (`LGraphTriggerAction`) derive from this tuple — adding a new action is
+ * a one-place change. Keep in lockstep with {@link LGraphTriggerEvent}.
+ */
+export const LGraphTriggerActions = [
+  'node:property:changed',
+  'node:slot-errors:changed',
+  'node:slot-links:changed',
+  'node:slot-label:changed'
+] as const satisfies readonly LGraphTriggerEvent['type'][]
+
+export type LGraphTriggerAction = (typeof LGraphTriggerActions)[number]
 
 export type LGraphTriggerParam<A extends LGraphTriggerAction> = Extract<
   LGraphTriggerEvent,

src/lib/litegraph/src/types/widgets.ts

@@ -375,6 +375,21 @@ export interface IRangeWidget extends IBaseWidget<
 export type TWidgetType = IWidget['type']
 export type TWidgetValue = IWidget['value']
 
+/**
+ * Runtime type guard for {@link TWidgetValue}. Accepts any value shape that a
+ * widget can legally hold: primitives (`string`, `number`, `boolean`),
+ * non-null objects (arrays, plain objects), or `undefined`. Rejects `null` and
+ * functions. Used at serialization / migration boundaries that consume
+ * `unknown` payloads (e.g. `widgets_values`).
+ */
+export function isWidgetValue(value: unknown): value is TWidgetValue {
+  if (value === undefined) return true
+  if (typeof value === 'string') return true
+  if (typeof value === 'number') return true
+  if (typeof value === 'boolean') return true
+  return value !== null && typeof value === 'object'
+}
+
 /**
  * The base type for all widgets.  Should not be implemented directly.
  * @template TValue The type of value this widget holds.

src/stores/appModeStore.ts

@@ -267,9 +267,14 @@ export const useAppModeStore = defineStore('appMode', () => {
   function updateInputConfig(widget: IBaseWidget, config: InputWidgetConfig) {
     const targetEntityId = widget.entityId
     if (!targetEntityId) return
-    const entry = selectedInputs.value.find(([id]) => id === targetEntityId)
-    if (!entry) return
-    entry[2] = { ...entry[2], ...config }
+    const index = selectedInputs.value.findIndex(
+      ([id]) => id === targetEntityId
+    )
+    if (index === -1) return
+    // Replace the tuple rather than mutating its `[2]` slot in place so
+    // reactive consumers that key off entry identity see the change.
+    const [id, type, options] = selectedInputs.value[index]
+    selectedInputs.value.splice(index, 1, [id, type, { ...options, ...config }])
   }
 
   return {