8000 gh-120057: Add os.reload_environ() function (#126268) · python/cpython@4a0d574 · GitHub
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Commit 4a0d574

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vstinnerpicnixzAA-Turner
authored
gh-120057: Add os.reload_environ() function (#126268)
Replace the os.environ.refresh() method with a new os.reload_environ() function. Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com> Co-authored-by: Adam Turner <9087854+AA-Turner@users.noreply.github.com>
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‎Doc/library/os.rst

Lines changed: 24 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -193,10 +193,6 @@ process and user.
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to the environment made after this time are not reflected in :data:`os.environ`,
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except for changes made by modifying :data:`os.environ` directly.
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The :meth:`!os.environ.refresh` method updates :data:`os.environ` with
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changes to the environment made by :func:`os.putenv`, by
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:func:`os.unsetenv`, or made outside Python in the same process.
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This mapping may be used to modify the environment as well as query the
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environment. :func:`putenv` will be called automatically when the mapping
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is modified.
@@ -226,12 +222,13 @@ process and user.
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:data:`os.environ`, and when one of the :meth:`pop` or :meth:`clear` methods is
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called.
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.. seealso::
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The :func:`os.reload_environ` function.
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.. versionchanged:: 3.9
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Updated to support :pep:`584`'s merge (``|``) and update (``|=``) operators.
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.. versionchanged:: 3.14
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Added the :meth:`!os.environ.refresh` method.
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.. data:: environb
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@@ -249,6 +246,24 @@ process and user.
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Updated to support :pep:`584`'s merge (``|``) and update (``|=``) operators.
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.. function:: reload_environ()
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The :data:`os.environ` and :data:`os.environb` mappings are a cache of
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environment variables at the time that Python started.
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As such, changes to the current process environment are not reflected
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if made outside Python, or by :func:`os.putenv` or :func:`os.unsetenv`.
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Use :func:`!os.reload_environ` to update :data:`os.environ` and :data:`os.environb`
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with any such changes to the current process environment.
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.. warning::
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This function is not thread-safe. Calling it while the environment is
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being modified in an other thread is an undefined behavior. Reading from
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:data:`os.environ` or :data:`os.environb`, or calling :func:`os.getenv`
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while reloading, may return an empty result.
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.. versionadded:: next
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.. function:: chdir(path)
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fchdir(fd)
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getcwd()
@@ -568,7 +583,7 @@ process and user.
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of :data:`os.environ`. This also applies to :func:`getenv` and :func:`getenvb`, which
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respectively use :data:`os.environ` and :data:`os.environb` in their implementations.
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See also the :data:`os.environ.refresh() <os.environ>` method.
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See also the :func:`os.reload_environ` function.
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.. note::
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@@ -818,7 +833,7 @@ process and user.
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don't update :data:`os.environ`, so it is actually preferable to delete items of
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:data:`os.environ`.
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See also the :data:`os.environ.refresh() <os.environ>` method.
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See also the :func:`os.reload_environ` function.
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.. audit-event:: os.unsetenv key os.unsetenv
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‎Doc/whatsnew/3.14.rst

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -365,9 +365,10 @@ operator
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os
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--
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* Add the :data:`os.environ.refresh() <os.environ>` method to update
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:data:`os.environ` with changes to the environment made by :func:`os.putenv`,
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by :func:`os.unsetenv`, or made outside Python in the same process.
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* Add the :func:`os.reload_environ` function to update :data:`os.environ` and
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:data:`os.environb` with changes to the environment made by
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:func:`os.putenv`, by :func:`os.unsetenv`, or made outside Python in the
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same process.
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(Contributed by Victor Stinner in :gh:`120057`.)
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‎Lib/os.py

Lines changed: 14 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -765,17 +765,6 @@ def __ror__(self, other):
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new.update(self)
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return new
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if _exists("_create_environ"):
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def refresh(self):
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data = _create_environ()
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if name == 'nt':
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data = {self.encodekey(key): value
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for key, value in data.items()}
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# modify in-place to keep os.environb in sync
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self._data.clear()
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self._data.update(data)
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def _create_environ_mapping():
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if name == 'nt':
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# Where Env Var Names Must Be UPPERCASE
@@ -810,6 +799,20 @@ def decode(value):
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del _create_environ_mapping
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if _exists("_create_environ"):
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def reload_environ():
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data = _create_environ()
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if name == 'nt':
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encodekey = environ.encodekey
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data = {encodekey(key): value
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for key, value in data.items()}
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# modify in-place to keep os.environb in sync
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env_data = environ._data
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env_data.clear()
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env_data.update(data)
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def getenv(key, default=None):
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"""Get an environment variable, return None if it doesn't exist.
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The optional second argument can specify an alternate default.

‎Lib/test/test_os.py

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -1298,8 +1298,8 @@ def test_ror_operator(self):
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self._test_underlying_process_env('_A_', '')
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self._test_underlying_process_env(overridden_key, original_value)
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def test_refresh(self):
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# Test os.environ.refresh()
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def test_reload_environ(self):
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# Test os.reload_environ()
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has_environb = hasattr(os, 'environb')
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# Test with putenv() which doesn't update os.environ
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if has_environb:
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self.assertEqual(os.environb[b'test_env'], b'python_value')
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1312-
os.environ.refresh()
1312+
os.reload_environ()
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self.assertEqual(os.environ['test_env'], 'new_value')
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if has_environb:
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self.assertEqual(os.environb[b'test_env'], b'new_value')
@@ -1320,28 +1320,28 @@ def test_refresh(self):
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if has_environb:
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self.assertEqual(os.environb[b'test_env'], b'new_value')
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1323-
os.environ.refresh()
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os.reload_environ()
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self.assertNotIn('test_env', os.environ)
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if has_environb:
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self.assertNotIn(b'test_env', os.environb)
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13281328
if has_environb:
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# test os.environb.refresh() with putenv()
1329+
# test reload_environ() on os.environb with putenv()
13301330
os.environb[b'test_env'] = b'python_value2'
13311331
os.putenv("test_env", "new_value2")
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self.assertEqual(os.environb[b'test_env'], b'python_value2')
13331333
self.assertEqual(os.environ['test_env'], 'python_value2')
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1335-
os.environb.refresh()
1335+
os.reload_environ()
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self.assertEqual(os.environb[b'test_env'], b'new_value2')
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self.assertEqual(os.environ['test_env'], 'new_value2')
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1339-
# test os.environb.refresh() with unsetenv()
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# test reload_environ() on os.environb with unsetenv()
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os.unsetenv('test_env')
13411341
self.assertEqual(os.environb[b'test_env'], b'new_value2')
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self.assertEqual(os.environ['test_env'], 'new_value2')
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1344-
os.environb.refresh()
1344+
os.reload_environ()
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self.assertNotIn(b'test_env', os.environb)
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self.assertNotIn('test_env', os.environ)
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‎Misc/NEWS.d/next/Library/2024-11-01-10-35-49.gh-issue-120057.YWy81Q.rst

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Original file line numberDiff line numberDiff line change
@@ -0,0 +1,2 @@
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Replace the ``os.environ.refresh()`` method with a new
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:func:`os.reload_environ` function. Patch by Victor Stinner.

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