From: Nice Zombies <nineteendo19d0@gmail.com>
Date: Thu, 18 Apr 2024 07:26:34 +0000 (+0200)
Subject: gh-117641: Improve the perfornance of posixpath.commonpath() (#117652)
X-Git-Tag: v3.13.0b1~363
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=b848b944bb4730ab4dcaeb15b0b1713c3f68ec7d;p=thirdparty%2FPython%2Fcpython.git

gh-117641: Improve the perfornance of posixpath.commonpath() (#117652)
---

diff --git a/Lib/posixpath.py b/Lib/posixpath.py
index 79cda50753e0..f1960ddb88e5 100644
--- a/Lib/posixpath.py
+++ b/Lib/posixpath.py
@@ -550,7 +550,7 @@ def commonpath(paths):
         split_paths = [path.split(sep) for path in paths]
 
         try:
-            isabs, = set(p[:1] == sep for p in paths)
+            isabs, = {p.startswith(sep) for p in paths}
         except ValueError:
             raise ValueError("Can't mix absolute and relative paths") from None
 
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-04-08-19-30-38.gh-issue-117641.oaBGSJ.rst b/Misc/NEWS.d/next/Core and Builtins/2024-04-08-19-30-38.gh-issue-117641.oaBGSJ.rst
new file mode 100644
index 000000000000..e313c133b721
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2024-04-08-19-30-38.gh-issue-117641.oaBGSJ.rst	
@@ -0,0 +1 @@
+Speedup :func:`os.path.commonpath` on Unix.