fix: serialize subgraph instance widget values

src/core/graph/subgraph/subgraphNodePromotion.test.ts

@@ -253,7 +253,7 @@ describe('Subgraph proxyWidgets', () => {
     expect(subgraphNode.widgets).toHaveLength(0)
   })
 
-  test('serialize does not produce widgets_values for promoted views', () => {
+  test('serialize stores widgets_values for promoted views', () => {
     const [subgraphNode, innerNodes, innerIds] = setupSubgraph(1)
     innerNodes[0].addWidget('text', 'stringWidget', 'value', () => {})
     usePromotionStore().setPromotions(
@@ -265,9 +265,7 @@ describe('Subgraph proxyWidgets', () => {
 
     const serialized = subgraphNode.serialize()
 
-    // SubgraphNode doesn't set serialize_widgets, so widgets_values is absent.
-    // Even if it were set, views have serialize: false and would be skipped.
-    expect(serialized.widgets_values).toBeUndefined()
+    expect(serialized.widgets_values).toEqual(['value'])
   })
 
   test('serialize preserves proxyWidgets in properties', () => {

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

@@ -91,5 +91,45 @@ describe('SubgraphNode multi-instance widget isolation', () => {
     expect(widgets2[0].value).toBe(20)
     expect(widgets1[0].serializeValue!(instance1, 0)).toBe(10)
     expect(widgets2[0].serializeValue!(instance2, 0)).toBe(20)
+    expect(instance1.serialize().widgets_values).toEqual([10])
+    expect(instance2.serialize().widgets_values).toEqual([20])
+  })
+
+  it('round-trips per-instance widget values through serialize and configure', () => {
+    const subgraph = createTestSubgraph({
+      inputs: [{ name: 'value', type: 'number' }]
+    })
+
+    const { node } = createNodeWithWidget('TestNode', 0)
+    subgraph.add(node)
+    subgraph.inputNode.slots[0].connect(node.inputs[0], node)
+
+    const originalInstance = createTestSubgraphNode(subgraph, { id: 301 })
+    originalInstance.configure({
+      id: 301,
+      type: subgraph.id,
+      pos: [100, 100],
+      size: [200, 100],
+      inputs: [],
+      outputs: [],
+      mode: 0,
+      order: 0,
+      flags: {},
+      properties: { proxyWidgets: [['-1', 'widget']] },
+      widgets_values: [33]
+    })
+
+    const serialized = originalInstance.serialize()
+
+    const restoredInstance = createTestSubgraphNode(subgraph, { id: 302 })
+    restoredInstance.configure({
+      ...serialized,
+      id: 302,
+      type: subgraph.id
+    })
+
+    const restoredWidget = restoredInstance.widgets?.[0]
+    expect(restoredWidget?.value).toBe(33)
+    expect(restoredWidget?.serializeValue?.(restoredInstance, 0)).toBe(33)
   })
 })

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

@@ -1600,28 +1600,7 @@ export class SubgraphNode extends LGraphNode implements BaseLGraph {
     ctx.restore()
   }
 
-  /**
-   * Synchronizes widget values from this SubgraphNode instance to the
-   * corresponding widgets in the subgraph definition before serialization.
-   * This ensures nested subgraph widget values are preserved when saving.
-   */
   override serialize(): ISerialisedNode {
-    // Sync widget values to subgraph definition before serialization.
-    // Only sync for inputs that are linked to a promoted widget via _widget.
-    for (const input of this.inputs) {
-      if (!input._widget) continue
-
-      const subgraphInput =
-        input._subgraphSlot ??
-        this.subgraph.inputNode.slots.find((slot) => slot.name === input.name)
-      if (!subgraphInput) continue
-
-      const connectedWidgets = subgraphInput.getConnectedWidgets()
-      for (const connectedWidget of connectedWidgets) {
-        connectedWidget.value = input._widget.value
-      }
-    }
-
     // Write promotion store state back to properties for serialization
     const entries = usePromotionStore().getPromotions(
       this.rootGraph.id,
@@ -1629,7 +1608,21 @@ export class SubgraphNode extends LGraphNode implements BaseLGraph {
     )
     this.properties.proxyWidgets = this._serializeEntries(entries)
 
-    return super.serialize()
+    const serialized = super.serialize()
+    const views = this._getPromotedViews()
+
+    if (views.length > 0) {
+      serialized.widgets_values = views.map((view) => {
+        const value = view.serializeValue
+          ? view.serializeValue(this, -1)
+          : view.value
+        return value != null && typeof value === 'object'
+          ? JSON.parse(JSON.stringify(value))
+          : (value ?? null)
+      })
+    }
+
+    return serialized
   }
   override clone() {
     const clone = super.clone()