fix: harden subgraph disconnect cleanup for stale links

Amp-Thread-ID: https://ampcode.com/threads/T-019c9bb5-a77c-72ef-9b51-5394c20ee671
Co-authored-by: Amp <amp@ampcode.com>

Author: DrJKL

src/lib/litegraph/src/subgraph/SubgraphIO.test.ts

@@ -323,6 +323,35 @@ describe('SubgraphIO - Input Slot Dual-Nature Behavior', () => {
     expect(internalNode.onConnectionsChange).toHaveBeenCalled()
   })
 
+  subgraphTest(
+    'disconnects subgraph-input links even when link origin_slot points to a missing slot',
+    ({ subgraphWithNode }) => {
+      const { subgraph } = subgraphWithNode
+      const internalNode = new LGraphNode('Internal Target')
+      internalNode.addInput('in', '*')
+      subgraph.add(internalNode)
+
+      const subgraphInput = subgraph.inputNode.slots[0]
+      const link = subgraphInput.connect(internalNode.inputs[0], internalNode)
+      if (!link) throw new Error('Expected link')
+
+      // Simulate stale legacy/corrupt topology where the slot index no longer resolves.
+      link.origin_slot = 999
+
+      new ToInputFromIoNodeLink(
+        subgraph,
+        subgraph.inputNode,
+        subgraphInput,
+        undefined,
+        LinkDirection.CENTER,
+        link
+      ).disconnect()
+
+      expect(internalNode.inputs[0].link).toBeNull()
+      expect(subgraph.links.get(link.id)).toBeUndefined()
+    }
+  )
+
   subgraphTest(
     'handles slot renaming with active connections',
     ({ subgraphWithNode }) => {
@@ -509,6 +538,31 @@ describe('SubgraphIO - Output Slot Dual-Nature Behavior', () => {
       expect(subgraph.outputs[0].displayName).toBe('new_name')
     }
   )
+
+  subgraphTest(
+    'cleans stale subgraph-output linkIds while disconnecting active output links',
+    ({ subgraphWithNode }) => {
+      const { subgraph } = subgraphWithNode
+
+      const internalNode = new LGraphNode('Internal Source')
+      internalNode.addOutput('out', '*')
+      subgraph.add(internalNode)
+
+      const subgraphOutput = subgraph.outputNode.slots[0]
+      const link = subgraphOutput.connect(internalNode.outputs[0], internalNode)
+      if (!link) throw new Error('Expected link')
+
+      // Simulate stale/corrupt bookkeeping where a dead link id remains.
+      const staleLinkId = 999_999
+      subgraphOutput.linkIds.push(staleLinkId)
+
+      subgraphOutput.disconnect()
+
+      expect(subgraphOutput.linkIds).toEqual([])
+      expect(subgraph.links.get(link.id)).toBeUndefined()
+      expect(internalNode.outputs[0].links).toEqual([])
+    }
+  )
 })
 
 describe('SubgraphIO - Boundary Connection Management', () => {

src/lib/litegraph/src/subgraph/SubgraphInputNode.ts

@@ -171,19 +171,32 @@ export class SubgraphInputNode
   ): void {
     const { subgraph } = this
 
+    const slotIndex = node.inputs.findIndex((inp) => inp === input)
+    if (slotIndex === -1) {
+      console.warn('disconnectNodeInput: target input slot not found', this)
+      return
+    }
+
     const subgraphInput = link ? this.slots.at(link.origin_slot) : undefined
     if (!subgraphInput) {
       console.warn(
         'disconnectNodeInput: subgraphInput not found',
         this,
         link?.origin_slot
       )
-      return
-    }
 
-    const slotIndex = node.inputs.findIndex((inp) => inp === input)
-    if (slotIndex === -1) {
-      console.warn('disconnectNodeInput: target input slot not found', this)
+      if (input._floatingLinks?.size) {
+        for (const floatingLink of input._floatingLinks) {
+          subgraph.removeFloatingLink(floatingLink)
+        }
+      }
+
+      input.link = null
+      if (link) {
+        subgraph.disconnectLink(link, 'output')
+        subgraph._version++
+      }
+      subgraph.setDirtyCanvas(false, true)
       return
     }
 

src/lib/litegraph/src/subgraph/SubgraphOutput.ts

@@ -153,5 +153,7 @@ export class SubgraphOutput extends SubgraphSlot {
         slot: this
       })
     }
+
+    this.linkIds.length = 0
   }
 }