fix: Add unit tests for resolveSubgraphInputLink (#9293)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/composables/useCurveEditor.ts

@@ -9,21 +9,6 @@ interface UseCurveEditorOptions {
   modelValue: Ref<CurvePoint[]>
 }
 
-function insertSorted(
-  points: CurvePoint[],
-  point: CurvePoint
-): [CurvePoint[], number] {
-  let lo = 0
-  let hi = points.length
-  while (lo < hi) {
-    const mid = (lo + hi) >>> 1
-    if (points[mid][0] < point[0]) lo = mid + 1
-    else hi = mid
-  }
-  const result = [...points.slice(0, lo), point, ...points.slice(lo)]
-  return [result, lo]
-}
-
 export function useCurveEditor({ svgRef, modelValue }: UseCurveEditorOptions) {
   const dragIndex = ref(-1)
   let cleanupDrag: (() => void) | null = null
@@ -92,10 +77,11 @@ export function useCurveEditor({ svgRef, modelValue }: UseCurveEditorOptions) {
     if (e.ctrlKey) return
 
     const newPoint: CurvePoint = [x, y]
-    const [newPoints, insertIndex] = insertSorted(modelValue.value, newPoint)
+    const newPoints: CurvePoint[] = [...modelValue.value, newPoint]
+    newPoints.sort((a, b) => a[0] - b[0])
     modelValue.value = newPoints
 
-    startDrag(insertIndex, e)
+    startDrag(newPoints.indexOf(newPoint), e)
   }
 
   function startDrag(index: number, e: PointerEvent) {
@@ -120,10 +106,11 @@ export function useCurveEditor({ svgRef, modelValue }: UseCurveEditorOptions) {
       if (dragIndex.value < 0) return
       const [x, y] = svgCoords(ev)
       const movedPoint: CurvePoint = [x, y]
-      const remaining = modelValue.value.filter((_, i) => i !== dragIndex.value)
-      const [newPoints, newIndex] = insertSorted(remaining, movedPoint)
+      const newPoints = [...modelValue.value]
+      newPoints[dragIndex.value] = movedPoint
+      newPoints.sort((a, b) => a[0] - b[0])
       modelValue.value = newPoints
-      dragIndex.value = newIndex
+      dragIndex.value = newPoints.indexOf(movedPoint)
     }
 
     const endDrag = () => {

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

@@ -121,6 +121,68 @@ describe('resolveSubgraphInputLink', () => {
     expect(result).toBe('seed_input')
   })
 
+  test('skips broken links where getLink returns undefined', () => {
+    const { subgraph, subgraphNode } = createSubgraphSetup('prompt')
+    addLinkedInteriorInput(subgraph, 'prompt', 'valid_input', 'valid')
+    const broken = addLinkedInteriorInput(
+      subgraph,
+      'prompt',
+      'broken_input',
+      'broken'
+    )
+
+    const originalGetLink = subgraph.getLink.bind(subgraph)
+    vi.spyOn(subgraph, 'getLink').mockImplementation((linkId) => {
+      if (typeof linkId !== 'number') return originalGetLink(linkId)
+      if (linkId === broken.linkId) return undefined
+      return originalGetLink(linkId)
+    })
+
+    const result = resolveSubgraphInputLink(
+      subgraphNode,
+      'prompt',
+      ({ targetInput }) => targetInput.name
+    )
+
+    expect(result).toBe('valid_input')
+  })
+
+  test('returns result from latest connection when multiple links resolve', () => {
+    const { subgraph, subgraphNode } = createSubgraphSetup('prompt')
+    addLinkedInteriorInput(subgraph, 'prompt', 'older_input', 'older')
+    addLinkedInteriorInput(subgraph, 'prompt', 'newer_input', 'newer')
+
+    const result = resolveSubgraphInputLink(
+      subgraphNode,
+      'prompt',
+      ({ targetInput }) => targetInput.name
+    )
+
+    expect(result).toBe('newer_input')
+  })
+
+  test('falls back to earlier link when latest resolve callback returns undefined', () => {
+    const { subgraph, subgraphNode } = createSubgraphSetup('prompt')
+    addLinkedInteriorInput(subgraph, 'prompt', 'fallback_input', 'fallback')
+    const newer = addLinkedInteriorInput(
+      subgraph,
+      'prompt',
+      'skipped_input',
+      'skipped'
+    )
+
+    const result = resolveSubgraphInputLink(
+      subgraphNode,
+      'prompt',
+      ({ targetInput }) => {
+        if (targetInput.link === newer.linkId) return undefined
+        return targetInput.name
+      }
+    )
+
+    expect(result).toBe('fallback_input')
+  })
+
   test('caches getTargetWidget result within the same callback evaluation', () => {
     const { subgraph, subgraphNode } = createSubgraphSetup('model')
     const linked = addLinkedInteriorInput(