From 35376658061cc35aaf9316eca3100af6d0445357 Mon Sep 17 00:00:00 2001
From: Tianyi Cui <53024+tianyicui@users.noreply.github.com>
Date: Wed, 29 Jul 2026 04:19:04 +0800
Subject: [PATCH] fix(subprocess): honor Windows environment key casing

---
 packages/subprocess/subprocess-local/src/index.ts    | 12 ++++++++++--
 .../subprocess/subprocess-local/tests/local.spec.ts  |  4 +++-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/packages/subprocess/subprocess-local/src/index.ts b/packages/subprocess/subprocess-local/src/index.ts
index 03755cd9ea..4c5cad8018 100644
--- a/packages/subprocess/subprocess-local/src/index.ts
+++ b/packages/subprocess/subprocess-local/src/index.ts
@@ -102,9 +102,9 @@ export class LocalSubprocessService extends SubprocessService {
   }
 
   private executableCandidates(command: string, env: NodeJS.ProcessEnv): string[] {
-    const path = env.PATH ?? ''
+    const path = environmentValue(env, 'PATH') ?? ''
     const extensions = process.platform === 'win32' && extname(command) === ''
-      ? (env.PATHEXT ?? '.COM;.EXE;.BAT;.CMD').split(';')
+      ? (environmentValue(env, 'PATHEXT') ?? '.COM;.EXE;.BAT;.CMD').split(';')
       : ['']
     return path.split(delimiter).flatMap(directory =>
       directory === '' ? [] : extensions.map(extension => resolve(this.cwd, directory, command + extension)))
@@ -156,4 +156,12 @@ export class LocalSubprocessService extends SubprocessService {
   }
 }
 
+/** Read a Windows environment key using the platform's case-insensitive semantics. */
+function environmentValue(env: NodeJS.ProcessEnv, name: 'PATH' | 'PATHEXT'): string | undefined {
+  const exact = env[name]
+  if (exact !== undefined || process.platform !== 'win32') return exact
+  const normalized = name.toUpperCase()
+  return Object.entries(env).find(([key]) => key.toUpperCase() === normalized)?.[1]
+}
+
 export default LocalSubprocessService
diff --git a/packages/subprocess/subprocess-local/tests/local.spec.ts b/packages/subprocess/subprocess-local/tests/local.spec.ts
index 6ce3d06b8e..4662283aad 100644
--- a/packages/subprocess/subprocess-local/tests/local.spec.ts
+++ b/packages/subprocess/subprocess-local/tests/local.spec.ts
@@ -62,8 +62,10 @@ describe('LocalSubprocessService', () => {
     }).executableCandidates.bind(service)
     const platform = vi.spyOn(process, 'platform', 'get').mockReturnValue('win32')
     try {
-      expect(candidates('tool', { PATH: `${delimiter}/bin`, PATHEXT: '.EXE;.CMD' }))
+      expect(candidates('tool', { Path: `${delimiter}/bin`, PathExt: '.EXE;.CMD' }))
         .toEqual(['/bin/tool.EXE', '/bin/tool.CMD'])
+      expect(candidates('tool', { Path: '/ambient', PATH: '/explicit', PATHEXT: '.EXE' }))
+        .toEqual(['/explicit/tool.EXE'])
       expect(candidates('tool.exe', {})).toEqual([])
       expect(candidates('tool', { PATH: '/bin' })).toHaveLength(4)
     } finally {