From f5b0ce7d21c7a820fcce2bb902467cf2700006bf Mon Sep 17 00:00:00 2001
From: Xylar Asay-Davis <xylarstorm@gmail.com>
Date: Mon, 30 Mar 2026 18:40:54 +0200
Subject: [PATCH 1/2] Fix get_editable_install_dir for non-editable install

---
 mpas_analysis/__main__.py | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mpas_analysis/__main__.py b/mpas_analysis/__main__.py
index 155b5d824..1cd665b8d 100644
--- a/mpas_analysis/__main__.py
+++ b/mpas_analysis/__main__.py
@@ -943,6 +943,9 @@ def get_editable_install_dir(package_name):
 
     direct_url = Distribution.from_name(package_name).read_text(
         'direct_url.json')
+    if direct_url is None:
+            return None
+
     contents = json.loads(direct_url)
     pkg_is_editable = contents.get("dir_info", {}).get("editable", False)
     if pkg_is_editable and 'url' in contents:

From a910bf71b9383fad233a8099dd8b1d69e4ab258f Mon Sep 17 00:00:00 2001
From: Xylar Asay-Davis <xylarstorm@gmail.com>
Date: Mon, 30 Mar 2026 18:41:21 +0200
Subject: [PATCH 2/2] Add a unit test to make sure the fix works

---
 mpas_analysis/test/test_main.py | 36 +++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)
 create mode 100644 mpas_analysis/test/test_main.py

diff --git a/mpas_analysis/test/test_main.py b/mpas_analysis/test/test_main.py
new file mode 100644
index 000000000..5270ec47c
--- /dev/null
+++ b/mpas_analysis/test/test_main.py
@@ -0,0 +1,36 @@
+# This software is open source software available under the BSD-3 license.
+#
+# Copyright (c) 2022 Triad National Security, LLC. All rights reserved.
+# Copyright (c) 2022 Lawrence Livermore National Security, LLC. All rights
+# reserved.
+# Copyright (c) 2022 UT-Battelle, LLC. All rights reserved.
+#
+# Additional copyright and license information can be found in the LICENSE file
+# distributed with this code, or at
+# https://raw.githubusercontent.com/MPAS-Dev/MPAS-Analysis/main/LICENSE
+"""
+Regression tests for helpers in ``mpas_analysis.__main__``.
+"""
+
+import os
+from unittest.mock import Mock, patch
+
+from mpas_analysis.test import TestCase
+
+
+# Importing mpas_analysis.__main__ triggers matplotlib imports in some test
+# environments, so use a writable cache directory.
+os.environ.setdefault('MPLCONFIGDIR', '/tmp/matplotlib')
+
+import mpas_analysis.__main__ as main
+
+
+class TestMain(TestCase):
+    def test_get_editable_install_dir_without_direct_url(self):
+        distribution = Mock()
+        distribution.read_text.return_value = None
+
+        with patch.object(main.Distribution, 'from_name',
+                          return_value=distribution):
+            self.assertEqual(main.get_editable_install_dir('mpas_analysis'),
+                             None)