[Lldb-commits] [lldb] [lldb][Windows] Use extended path prefix for rmtree (PR #209409)

[Charles Zablit via lldb-commits]

https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/209409

Prepend the build dir path with the `\\?\` prefix (https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation?tabs=registry) to allow deleting directories that have paths longer than 260 characters.

This is a recurring problem in Swiftlang.

>From fa2a80b744944f03b760bb071cb659ebc98fa3b3 Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Tue, 14 Jul 2026 10:18:34 +0100
Subject: [PATCH] [lldb][Windows] Use extended path prefix for rmtree

---
 lldb/packages/Python/lldbsuite/test/lldbtest.py | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/lldb/packages/Python/lldbsuite/test/lldbtest.py b/lldb/packages/Python/lldbsuite/test/lldbtest.py
index a9c229be1a771..2fc8601f93974 100644
--- a/lldb/packages/Python/lldbsuite/test/lldbtest.py
+++ b/lldb/packages/Python/lldbsuite/test/lldbtest.py
@@ -846,7 +846,12 @@ def _ignore_enoent(func, path, exc_info):
                     return
                 raise exc_info[1]
 
-            shutil.rmtree(bdir, onerror=_ignore_enoent)
+            # Delete via the \\?\ extended length path prefix so rmtree can
+            # remove build artifacts whose full path exceeds MAX_PATH (260).
+            rmtree_target = bdir
+            if sys.platform == "win32":
+                rmtree_target = "\\\\?\\" + bdir
+            shutil.rmtree(rmtree_target, onerror=_ignore_enoent)
         lldbutil.mkdir_p(bdir)
 
     def getBuildArtifact(self, name="a.out"):