From df97d03fd01b4b7f55985144e85ce640a9125e94 Mon Sep 17 00:00:00 2001
From: Victor Stinner <vstinner@python.org>
Date: Wed, 5 Jun 2024 09:39:30 +0200
Subject: [PATCH] Fix os.environb

---
 Lib/os.py           | 5 ++++-
 Lib/test/test_os.py | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/Lib/os.py b/Lib/os.py
index df212c06d985f98..9804136aa4bac42 100644
--- a/Lib/os.py
+++ b/Lib/os.py
@@ -790,7 +790,10 @@ def refresh(self):
                     data[encodekey(key)] = value
             else:
                 data = environ
-            self._data = data
+
+            # modify in-place to keep os.environb in sync
+            self._data.clear()
+            self._data.update(data)
 
 def _create_environ_mapping():
     if name == 'nt':
diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 38a327038fc1d15..74df151747f64be 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -1310,9 +1310,13 @@ def test_refresh(self):
         os.environ['test_env'] = 'python_value'
         putenv("test_env", "new_value")
         self.assertEqual(os.environ['test_env'], 'python_value')
+        if hasattr(os, 'environb'):
+            self.assertEqual(os.environb[b'test_env'], b'python_value')
 
         os.environ.refresh()
         self.assertEqual(os.environ['test_env'], 'new_value')
+        if hasattr(os, 'environb'):
+            self.assertEqual(os.environb[b'test_env'], b'new_value')
 
 
 class WalkTests(unittest.TestCase):