From 777cd60420b2d2a674e7dc186dd4f661c4f9f3f9 Mon Sep 17 00:00:00 2001
From: Alex Domingo <alex.domingo.toro@vub.be>
Date: Fri, 20 Sep 2024 13:32:26 +0200
Subject: [PATCH] avoid breaking Python environment by prepending CIME paths to
 PYTHONPATH

---
 CIME/utils.py | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/CIME/utils.py b/CIME/utils.py
index 85fa30017b0..e84d614b12b 100644
--- a/CIME/utils.py
+++ b/CIME/utils.py
@@ -820,12 +820,10 @@ def run_cmd(
     # or build a relative path and append `sys.path` to import
     # `standard_script_setup`. Providing `PYTHONPATH` fixes protential
     # broken paths in external python.
-    env.update(
-        {
-            "CIMEROOT": f"{get_cime_root()}",
-            "PYTHONPATH": f"{get_cime_root()}:{get_tools_path()}",
-        }
-    )
+    env_pythonpath = os.environ.get("PYTHONPATH", "").split(":")
+    cime_pythonpath = [f"{get_cime_root()}", f"{get_tools_path()}"] + env_pythonpath
+    env["PYTHONPATH"] = ":".join(filter(None, cime_pythonpath))
+    env["CIMEROOT"] = f"{get_cime_root()}"
 
     if timeout:
         with Timeout(timeout):