[bugfix] Allow removeInput/removeOutput on nodes without graph reference (#5053)

- Modified removeInput/removeOutput to skip disconnect operations when node has no graph
- Both methods now safely handle nodes that aren't part of a graph
- Added comprehensive tests for the new behavior
- Fixes #5037

src/lib/litegraph/src/LGraphNode.ts

@@ -1574,7 +1574,10 @@ export class LGraphNode
    * remove an existing output slot
    */
   removeOutput(slot: number): void {
-    this.disconnectOutput(slot)
+    // Only disconnect if node is part of a graph
+    if (this.graph) {
+      this.disconnectOutput(slot)
+    }
     const { outputs } = this
     outputs.splice(slot, 1)
 
@@ -1582,11 +1585,12 @@ export class LGraphNode
       const output = outputs[i]
       if (!output || !output.links) continue
 
-      for (const linkId of output.links) {
-        if (!this.graph) throw new NullGraphError()
-
-        const link = this.graph._links.get(linkId)
-        if (link) link.origin_slot--
+      // Only update link indices if node is part of a graph
+      if (this.graph) {
+        for (const linkId of output.links) {
+          const link = this.graph._links.get(linkId)
+          if (link) link.origin_slot--
+        }
       }
     }
 
@@ -1626,7 +1630,10 @@ export class LGraphNode
    * remove an existing input slot
    */
   removeInput(slot: number): void {
-    this.disconnectInput(slot, true)
+    // Only disconnect if node is part of a graph
+    if (this.graph) {
+      this.disconnectInput(slot, true)
+    }
     const { inputs } = this
     const slot_info = inputs.splice(slot, 1)
 
@@ -1634,9 +1641,11 @@ export class LGraphNode
       const input = inputs[i]
       if (!input?.link) continue
 
-      if (!this.graph) throw new NullGraphError()
-      const link = this.graph._links.get(input.link)
-      if (link) link.target_slot--
+      // Only update link indices if node is part of a graph
+      if (this.graph) {
+        const link = this.graph._links.get(input.link)
+        if (link) link.target_slot--
+      }
     }
     this.onInputRemoved?.(slot, slot_info[0])
     this.setDirtyCanvas(true, true)

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

@@ -656,4 +656,119 @@ describe('LGraphNode', () => {
       spy.mockRestore()
     })
   })
+
+  describe('removeInput/removeOutput on copied nodes', () => {
+    beforeEach(() => {
+      // Register a test node type so clone() can work
+      LiteGraph.registerNodeType('TestNode', LGraphNode)
+    })
+
+    test('should NOT throw error when calling removeInput on a copied node without graph', () => {
+      // Create a node with an input
+      const originalNode = new LGraphNode('Test Node')
+      originalNode.type = 'TestNode'
+      originalNode.addInput('input1', 'number')
+
+      // Clone the node (which creates a node without graph reference)
+      const copiedNode = originalNode.clone()
+
+      // This should NOT throw anymore - we can remove inputs on nodes without graph
+      expect(() => copiedNode!.removeInput(0)).not.toThrow()
+      expect(copiedNode!.inputs).toHaveLength(0)
+    })
+
+    test('should NOT throw error when calling removeOutput on a copied node without graph', () => {
+      // Create a node with an output
+      const originalNode = new LGraphNode('Test Node')
+      originalNode.type = 'TestNode'
+      originalNode.addOutput('output1', 'number')
+
+      // Clone the node (which creates a node without graph reference)
+      const copiedNode = originalNode.clone()
+
+      // This should NOT throw anymore - we can remove outputs on nodes without graph
+      expect(() => copiedNode!.removeOutput(0)).not.toThrow()
+      expect(copiedNode!.outputs).toHaveLength(0)
+    })
+
+    test('should skip disconnectInput/disconnectOutput when node has no graph', () => {
+      // Create nodes with input/output
+      const nodeWithInput = new LGraphNode('Test Node')
+      nodeWithInput.type = 'TestNode'
+      nodeWithInput.addInput('input1', 'number')
+
+      const nodeWithOutput = new LGraphNode('Test Node')
+      nodeWithOutput.type = 'TestNode'
+      nodeWithOutput.addOutput('output1', 'number')
+
+      // Clone nodes (no graph reference)
+      const clonedInput = nodeWithInput.clone()
+      const clonedOutput = nodeWithOutput.clone()
+
+      // Mock disconnect methods to verify they're not called
+      clonedInput!.disconnectInput = vi.fn()
+      clonedOutput!.disconnectOutput = vi.fn()
+
+      // Remove input/output - disconnect methods should NOT be called
+      clonedInput!.removeInput(0)
+      clonedOutput!.removeOutput(0)
+
+      expect(clonedInput!.disconnectInput).not.toHaveBeenCalled()
+      expect(clonedOutput!.disconnectOutput).not.toHaveBeenCalled()
+    })
+
+    test('should be able to removeInput on a copied node after adding to graph', () => {
+      // Create a graph and a node with an input
+      const graph = new LGraph()
+      const originalNode = new LGraphNode('Test Node')
+      originalNode.type = 'TestNode'
+      originalNode.addInput('input1', 'number')
+
+      // Clone the node and add to graph
+      const copiedNode = originalNode.clone()
+      expect(copiedNode).not.toBeNull()
+      graph.add(copiedNode!)
+
+      // This should work now that the node has a graph reference
+      expect(() => copiedNode!.removeInput(0)).not.toThrow()
+      expect(copiedNode!.inputs).toHaveLength(0)
+    })
+
+    test('should be able to removeOutput on a copied node after adding to graph', () => {
+      // Create a graph and a node with an output
+      const graph = new LGraph()
+      const originalNode = new LGraphNode('Test Node')
+      originalNode.type = 'TestNode'
+      originalNode.addOutput('output1', 'number')
+
+      // Clone the node and add to graph
+      const copiedNode = originalNode.clone()
+      expect(copiedNode).not.toBeNull()
+      graph.add(copiedNode!)
+
+      // This should work now that the node has a graph reference
+      expect(() => copiedNode!.removeOutput(0)).not.toThrow()
+      expect(copiedNode!.outputs).toHaveLength(0)
+    })
+
+    test('RerouteNode clone scenario - should be able to removeOutput and addOutput on cloned node', () => {
+      // This simulates the RerouteNode clone method behavior
+      const originalNode = new LGraphNode('Reroute')
+      originalNode.type = 'TestNode'
+      originalNode.addOutput('*', '*')
+
+      // Clone the node (simulating RerouteNode.clone)
+      const clonedNode = originalNode.clone()
+      expect(clonedNode).not.toBeNull()
+
+      // This should not throw - we should be able to modify outputs on a cloned node
+      expect(() => {
+        clonedNode!.removeOutput(0)
+        clonedNode!.addOutput('renamed', '*')
+      }).not.toThrow()
+
+      expect(clonedNode!.outputs).toHaveLength(1)
+      expect(clonedNode!.outputs[0].name).toBe('renamed')
+    })
+  })
 })