fix: subgraph promoted widget input label rename (#10195)

## Summary

Promoted primitive subgraph inputs (String, Int) render their link
anchor at the header position instead of the widget row. Renaming
subgraph input labels breaks the match entirely, causing connections to
detach from their widgets visually.

## Changes

- **What**: Fix widget-input slot positioning for promoted subgraph
inputs in both LiteGraph and Vue (Nodes 2.0) rendering modes
- `_arrangeWidgetInputSlots`: Removed Vue mode branch that skipped
setting `input.pos`. Promoted widget inputs aren't rendered as
`<InputSlot>` Vue components (NodeSlots filters them out), so
`input.pos` is the only position fallback
- `drawConnections`: Added pre-pass to arrange nodes with unpositioned
widget-input slots before link rendering. The background canvas renders
before the foreground canvas calls `arrange()`, so positions weren't set
on the first frame
- `SubgraphNode`: Sync `input.widget.name` with the display name on
label rename and initial setup. The `IWidgetLocator` name diverged from
`PromotedWidgetView.name` after rename, breaking all name-based
slot↔widget matching (`_arrangeWidgetInputSlots`, `getWidgetFromSlot`,
`getSlotFromWidget`)

## Review Focus

- The `_arrangeWidgetInputSlots` rewrite iterates `_concreteInputs`
directly instead of building a spread-copy map — simpler and avoids the
stale index issue
- `input.widget.name` is now kept in sync with the display name
(`input.label ?? subgraphInput.name`). This is a semantic shift from
using the raw internal name, but it's required for all name-based
matching to work after renames. The value is overwritten on deserialize
by `_setWidget` anyway
- The `_widget` fallback in `_arrangeWidgetInputSlots` is a safety net
for edge cases where the name still doesn't match (e.g., stale cache)

Fixes #9998

## Screenshots
<img width="847" height="476" alt="Screenshot 2026-03-17 at 3 05 32 PM"
src="https://github.com/user-attachments/assets/38f10563-f0bc-44dd-a1a5-f4a7832575d0"
/>
<img width="804" height="471" alt="Screenshot 2026-03-17 at 3 05 23 PM"
src="https://github.com/user-attachments/assets/3237a7ee-f3e5-4084-b330-371def3415bd"
/>
<img width="974" height="571" alt="Screenshot 2026-03-17 at 3 05 16 PM"
src="https://github.com/user-attachments/assets/cafdca46-8d9b-40e1-8561-02cbb25ee8f2"
/>
<img width="967" height="558" alt="Screenshot 2026-03-17 at 3 05 06 PM"
src="https://github.com/user-attachments/assets/fc03ce43-906c-474d-b3bc-ddf08eb37c75"
/>


┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10195-fix-subgraph-promoted-widget-input-slot-positions-after-label-rename-3266d73d365081dfa623dd94dd87c718)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Co-authored-by: jaeone94 <jaeone.prt@gmail.com>

src/lib/litegraph/src/LGraphNode.ts

@@ -295,6 +295,12 @@ export class LGraphNode
    */
   freeWidgetSpace?: number
 
+  /**
+   * Set to true when widget-backed input slot positions need recalculation.
+   * Cleared after arrange() runs. Avoids per-frame O(N) scans in drawConnections.
+   */
+  _widgetSlotsDirty = false
+
   locked?: boolean
 
   /** Execution order, automatically computed during run @see {@link LGraph.computeExecutionOrder} */
@@ -1992,6 +1998,7 @@ export class LGraphNode
     this.widgets ||= []
     const widget = toConcreteWidget(custom_widget, this, false) ?? custom_widget
     this.widgets.push(widget)
+    this._widgetSlotsDirty = true
 
     // Only register with store if node has a valid ID (is already in a graph).
     // If the node isn't in a graph yet (id === -1), registration happens
@@ -2031,9 +2038,11 @@ export class LGraphNode
         if (input._widget === widget) {
           input._widget = undefined
           input.widget = undefined
+          input.pos = undefined
         }
       }
     }
+    this._widgetSlotsDirty = true
 
     widget.onRemove?.()
     this.widgets.splice(widgetIndex, 1)
@@ -4206,40 +4215,29 @@ export class LGraphNode
    * Arranges the layout of the node's widget input slots.
    */
   private _arrangeWidgetInputSlots(): void {
-    if (!this.widgets) return
+    if (!this.widgets?.length) return
 
-    const slotByWidgetName = new Map<
-      string,
-      INodeInputSlot & { index: number }
-    >()
+    // Build a name→widget map for fast lookup.
+    const widgetByName = new Map<string, IBaseWidget>()
+    for (const w of this.widgets) widgetByName.set(w.name, w)
 
-    for (const [i, slot] of this.inputs.entries()) {
+    // Set widget-backed slot positions from widget Y coordinates.
+    // In Vue mode, promoted widget inputs are not rendered as <InputSlot>
+    // components (NodeSlots filters them out), so they have no DOM-registered
+    // position. input.pos serves as the fallback for getSlotPosition().
+    for (const [i, slot] of this._concreteInputs.entries()) {
       if (!isWidgetInputSlot(slot)) continue
 
-      slotByWidgetName.set(slot.widget.name, { ...slot, index: i })
-    }
-    if (!slotByWidgetName.size) return
+      // Prefer the slot's direct _widget binding (1:1 for promoted inputs).
+      // Fall back to name-map lookup for regular nodes without _widget set.
+      // Note: the name-map is ambiguous if two promoted inputs share a label;
+      // _widget avoids this since it is a direct reference.
+      const widget = slot._widget ?? widgetByName.get(slot.widget.name)
+      if (!widget) continue
 
-    // Only set custom pos if not using Vue positioning
-    // Vue positioning calculates widget slot positions dynamically
-    if (!LiteGraph.vueNodesMode) {
-      for (const widget of this.widgets) {
-        const slot = slotByWidgetName.get(widget.name)
-        if (!slot) continue
-
-        const actualSlot = this._concreteInputs[slot.index]
-        const offset = LiteGraph.NODE_SLOT_HEIGHT * 0.5
-        actualSlot.pos = [offset, widget.y + offset]
-        this._measureSlot(actualSlot, slot.index, true)
-      }
-    } else {
-      // For Vue positioning, just measure the slots without setting pos
-      for (const widget of this.widgets) {
-        const slot = slotByWidgetName.get(widget.name)
-        if (!slot) continue
-
-        this._measureSlot(this._concreteInputs[slot.index], slot.index, true)
-      }
+      const offset = LiteGraph.NODE_SLOT_HEIGHT * 0.5
+      slot.pos = [offset, widget.y + offset]
+      this._measureSlot(slot, i, true)
     }
   }
 
@@ -4269,6 +4267,7 @@ export class LGraphNode
       : 0
     this._arrangeWidgets(widgetStartY)
     this._arrangeWidgetInputSlots()
+    this._widgetSlotsDirty = false
   }
 
   /**