From a549f439384b4509b25639337ffea21c2e55d452 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Thu, 30 Jan 2025 01:02:31 +0100
Subject: [PATCH] gh-128779: Fix site venv() for system site-packages (#129184)

---
 Lib/site.py | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/Lib/site.py b/Lib/site.py
index 92bd1ccdadd9..9da8b6724e1c 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -633,12 +633,9 @@ def venv(known_paths):
         # Doing this here ensures venv takes precedence over user-site
         addsitepackages(known_paths, [sys.prefix])
 
-        # addsitepackages will process site_prefix again if its in PREFIXES,
-        # but that's ok; known_paths will prevent anything being added twice
         if system_site == "true":
-            PREFIXES.insert(0, sys.prefix)
+            PREFIXES += [sys.base_prefix, sys.base_exec_prefix]
         else:
-            PREFIXES = [sys.prefix]
             ENABLE_USER_SITE = False
 
     return known_paths
-- 
2.47.3