From 687b9e659c7393bee7093ea0c53945a61dc10ece Mon Sep 17 00:00:00 2001
From: filtered <176114999+webfiltered@users.noreply.github.com>
Date: Tue, 23 Sep 2025 04:13:38 +1000
Subject: [PATCH] Fix reroute ID 0 treated as invalid (#5723)
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## Summary

Fixes old logic bug from refactor
https://github.com/Comfy-Org/litegraph.js/pull/602/files

## Changes

- Fixes truthy refactor to explicitly check undefined

## Review Focus

No expectation that this will impact prod, however it may impact
extensions IF someone has explicitly been setting link parentId to 0.
This would be very strange, as it would cause unexpected behaviour in
other parts of the code (which all explicitly check `undefined`).

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5723-Fix-reroute-ID-0-treated-as-invalid-2766d73d365081568124ce1f85cdf84e)
by [Unito](https://www.unito.io)
---
 src/lib/litegraph/src/LLink.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/lib/litegraph/src/LLink.ts b/src/lib/litegraph/src/LLink.ts
index 58ae4e090..71b41f23d 100644
--- a/src/lib/litegraph/src/LLink.ts
+++ b/src/lib/litegraph/src/LLink.ts
@@ -205,7 +205,7 @@ export class LLink implements LinkSegment, Serialisable<SerialisableLLink> {
     network: Pick<ReadonlyLinkNetwork, 'reroutes'>,
     linkSegment: LinkSegment
   ): Reroute[] {
-    if (!linkSegment.parentId) return []
+    if (linkSegment.parentId === undefined) return []
     return network.reroutes.get(linkSegment.parentId)?.getReroutes() ?? []
   }
 
@@ -229,7 +229,7 @@ export class LLink implements LinkSegment, Serialisable<SerialisableLLink> {
     linkSegment: LinkSegment,
     rerouteId: RerouteId
   ): Reroute | null | undefined {
-    if (!linkSegment.parentId) return
+    if (linkSegment.parentId === undefined) return
     return network.reroutes
       .get(linkSegment.parentId)
       ?.findNextReroute(rerouteId)
@@ -498,7 +498,7 @@ export class LLink implements LinkSegment, Serialisable<SerialisableLLink> {
       target_slot: this.target_slot,
       type: this.type
     }
-    if (this.parentId) copy.parentId = this.parentId
+    if (this.parentId !== undefined) copy.parentId = this.parentId
     return copy
   }
 }