From 5330b2cfade28e48e608beb0a286c8646305f137 Mon Sep 17 00:00:00 2001
From: Teknium <127238744+teknium1@users.noreply.github.com>
Date: Thu, 16 Jul 2026 01:00:57 -0700
Subject: [PATCH] fix: use Windows-aware isabs for native paths under patched
 _IS_WINDOWS

Follow-up for salvaged PR #26790: on a POSIX host with _IS_WINDOWS
patched (test simulation), os.path.isabs rejects C:\Users\x and the
new relative-cwd recovery would mangle a perfectly absolute native
Windows path. Check ntpath.isabs first on the Windows branch.
---
 tools/environments/local.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/environments/local.py b/tools/environments/local.py
index acb390df4d9b..e18d1a7bd1f5 100644
--- a/tools/environments/local.py
+++ b/tools/environments/local.py
@@ -63,6 +63,12 @@ def _resolve_local_initial_cwd(cwd: str) -> str:
     expanded = os.path.expanduser(cwd) if cwd else os.getcwd()
     if _IS_WINDOWS:
         expanded = _msys_to_windows_path(expanded)
+        # Use the Windows-aware check explicitly: when _IS_WINDOWS is
+        # patched in tests on a POSIX host, os.path.isabs would reject
+        # ``C:\Users\x`` and mangle it through the relative branch.
+        import ntpath
+        if ntpath.isabs(expanded):
+            return expanded
     if os.path.isabs(expanded):
         return expanded