fix: refresh a placeholder's recorded size when it is collapsed

src/lib/litegraph/src/LGraphNode.test.ts

@@ -162,6 +162,63 @@ describe('LGraphNode', () => {
       expect(serialized.flags).toEqual({ collapsed: true })
     })
 
+    test('records the size it was collapsed from, so a resize survives collapsing', () => {
+      const placeholder = createPlaceholder({ flags: { collapsed: false } })
+      new LGraph().add(placeholder)
+      placeholder.setSize([777, 666])
+      placeholder.collapse()
+
+      const serialized = placeholder.serialize()
+
+      expect(serialized.size).toEqual([777, 666])
+      expect(serialized.flags).toEqual({ collapsed: true })
+    })
+
+    test('does not invent a recorded size on collapse when the file recorded none', () => {
+      const placeholder = createPlaceholder()
+      delete (placeholder.last_serialization as Partial<ISerialisedNode>).size
+      new LGraph().add(placeholder)
+      placeholder.setSize([777, 666])
+      placeholder.collapse()
+
+      expect(placeholder.serialize()).not.toHaveProperty('size')
+    })
+
+    test('restores the recorded size when expanding, rather than serializing the collapsed card measurement', () => {
+      const placeholder = createPlaceholder({ flags: { collapsed: false } })
+      new LGraph().add(placeholder)
+      placeholder.setSize([777, 666])
+      placeholder.collapse()
+      placeholder.setSize([80, 30])
+      placeholder.collapse()
+
+      expect(placeholder.last_serialization?.size).toEqual([777, 666])
+      expect(placeholder.serialize().size).toEqual([777, 666])
+    })
+
+    test('keeps the recorded size through an expand/collapse pair made before the card is re-measured', () => {
+      const placeholder = createPlaceholder({ flags: { collapsed: false } })
+      new LGraph().add(placeholder)
+      placeholder.setSize([777, 666])
+      placeholder.collapse()
+      placeholder.setSize([80, 30])
+      placeholder.collapse()
+      placeholder.collapse()
+
+      expect(placeholder.serialize().size).toEqual([777, 666])
+    })
+
+    test('replaces the recorded serialization rather than mutating the object it was configured from', () => {
+      const placeholder = createPlaceholder({ flags: { collapsed: false } })
+      const configuredFrom = placeholder.last_serialization!
+      new LGraph().add(placeholder)
+      placeholder.setSize([777, 666])
+      placeholder.collapse()
+
+      expect(configuredFrom.size).toEqual([140, 60])
+      expect(placeholder.last_serialization?.size).toEqual([777, 666])
+    })
+
     test('carries a live pin through', () => {
       const placeholder = createPlaceholder()
       new LGraph().add(placeholder)

src/lib/litegraph/src/LGraphNode.ts

@@ -3695,6 +3695,37 @@ export class LGraphNode
     if (!this.collapsible && !force) return
     if (!this.graph) throw new NullGraphError()
     this.graph.incrementVersion()
+
+    // A missing-node placeholder has no definition to re-derive an expanded
+    // size from, so `last_serialization.size` is the sole record of it and has
+    // to track the live node in BOTH directions. Both halves run before the
+    // flag flips, because in Vue nodes mode `size` is a DOM measurement of
+    // whichever card is currently rendered and the other card's measurement
+    // only lands a frame later:
+    //   collapsing captures `size` while it still measures the expanded card;
+    //   expanding restores `size`, which still measures the collapsed card, so
+    //   that neither a serialize() inside that window nor an immediate second
+    //   collapse can substitute the collapsed dimensions for the recorded ones.
+    // A recorded serialization without a size still gets none, matching
+    // `serialize()`.
+    const recordedSerialization = this.last_serialization
+    if (
+      this.constructor === LGraphNode &&
+      recordedSerialization?.size != null
+    ) {
+      if (this.flags.collapsed) {
+        this.size = recordedSerialization.size
+      } else {
+        // Replaced rather than mutated in place: `LGraph.configure()` assigns
+        // `last_serialization` by reference straight out of the caller's
+        // workflow data, which this node does not own.
+        this.last_serialization = {
+          ...recordedSerialization,
+          size: [this.size[0], this.size[1]]
+        }
+      }
+    }
+
     this.flags.collapsed = !this.flags.collapsed
     this.setDirtyCanvas(true, true)
   }