gh-120057: Add os.environ.refresh() method

Doc/library/os.rst

@@ -193,9 +193,9 @@ process and user.
    to the environment made after this time are not reflected in :data:`os.environ`,
    except for changes made by modifying :data:`os.environ` directly.
 
-   The :meth:`!os.environ.refresh()` method updates
-   :data:`os.environ` with changes to the environment made in the same process
-   outside Python or by :func:`os.putenv`.
+   The :meth:`!os.environ.refresh()` method updates :data:`os.environ` with
+   changes to the environment made by :func:`os.putenv`, by
+   :func:`os.unsetenv`, or made outside Python in the same process.
 
    This mapping may be used to modify the environment as well as query the
    environment.  :func:`putenv` will be called automatically when the mapping
@@ -568,6 +568,8 @@ process and user.
    of :data:`os.environ`. This also applies to :func:`getenv` and :func:`getenvb`, which
    respectively use :data:`os.environ` and :data:`os.environb` in their implementations.
 
+   See also the :data:`os.environ.refresh() <os.environ>` method.
+
    .. note::
 
       On some platforms, including FreeBSD and macOS, setting ``environ`` may
@@ -816,6 +818,8 @@ process and user.
    don't update :data:`os.environ`, so it is actually preferable to delete items of
    :data:`os.environ`.
 
+   See also the :data:`os.environ.refresh() <os.environ>` method.
+
    .. audit-event:: os.unsetenv key os.unsetenv
 
    .. versionchanged:: 3.9

Doc/whatsnew/3.14.rst

@@ -95,9 +95,9 @@ Added :func:`ast.compare` for comparing two ASTs.
 os
 --
 
-* Added the :meth:`os.environ.refresh() <os.environ>` method to update
-  :data:`os.environ` with environment changes made in the same process outside
-  Python or by :func:`os.putenv`.
+* Added the :data:`os.environ.refresh() <os.environ>` method to update
+  :data:`os.environ` with changes to the environment made by :func:`os.putenv`,
+  by :func:`os.unsetenv`, or made outside Python in the same process.
   (Contributed by Victor Stinner in :gh:`120057`.)
 
 

Lib/os.py

@@ -783,12 +783,10 @@ def __ror__(self, other):
 
     if _exists("_create_environ"):
         def refresh(self):
-            environ = _create_environ()
+            data = _create_environ()
             if name == 'nt':
                 data = {self.encodekey(key): value
-                        for key, value in environ.items()}
-            else:
-                data = environ
+                        for key, value in data.items()}
 
             # modify in-place to keep os.environb in sync
             self._data.clear()

Lib/test/test_os.py

@@ -1298,13 +1298,11 @@ def test_ror_operator(self):
         self._test_underlying_process_env('_A_', '')
         self._test_underlying_process_env(overridden_key, original_value)
 
-    @unittest.skipUnless(hasattr(os.environ, 'refresh'),
-                         'need os.environ.refresh()')
     def test_refresh(self):
-        # Test os.environ.refresh() with putenv() which doesn't update
-        # os.environ
+        # Test os.environ.refresh()
         has_environb = hasattr(os, 'environb')
 
+        # Test with putenv() which doesn't update os.environ
         os.environ['test_env'] = 'python_value'
         os.putenv("test_env", "new_value")
         self.assertEqual(os.environ['test_env'], 'python_value')
@@ -1316,6 +1314,17 @@ def test_refresh(self):
         if has_environb:
             self.assertEqual(os.environb[b'test_env'], b'new_value')
 
+        # Test with unsetenv() which doesn't update os.environ
+        os.unsetenv('test_env')
+        self.assertEqual(os.environ['test_env'], 'new_value')
+        if has_environb:
+            self.assertEqual(os.environb[b'test_env'], b'new_value')
+
+        os.environ.refresh()
+        self.assertNotIn('test_env', os.environ)
+        if has_environb:
+            self.assertNotIn(b'test_env', os.environb)
+
         if has_environb:
             # test os.environb.refresh()
             os.environb[b'test_env'] = b'python_value2'

Misc/NEWS.d/next/Library/2024-06-04-18-53-10.gh-issue-120057.RSD9_Z.rst

@@ -1,3 +1,4 @@
-Added the :meth:`os.environ.refresh() <os.environ>` method to update
-:data:`os.environ` with environment changes made in the same process outside
-Python or by :func:`os.putenv`. Patch by Victor Stinner.
+Added the :data:`os.environ.refresh() <os.environ>` method to update
+:data:`os.environ` with changes to the environment made by :func:`os.putenv`,
+by :func:`os.unsetenv`, or made outside Python in the same process.
+Patch by Victor Stinner.