pythongh-100131: Add optional delete parameter to tempfile.TemporaryD…

…irectory() (python#100132)

Add optional delete parameter to tempfile.TemporaryDirectory().

Co-authored-by: Gregory P. Smith <greg@krypto.org>

Doc/library/tempfile.rst

@@ -173,7 +173,7 @@ The module defines the following user-callable items:
  or text *mode* was specified).
 
 
-.. class:: TemporaryDirectory(suffix=None, prefix=None, dir=None, ignore_cleanup_errors=False)
+.. class:: TemporaryDirectory(suffix=None, prefix=None, dir=None, ignore_cleanup_errors=False, *, delete=True)
 
  This class securely creates a temporary directory using the same rules as :func:`mkdtemp`.
  The resulting object can be used as a context manager (see
@@ -195,13 +195,22 @@ The module defines the following user-callable items:
  (the :func:`cleanup` call, exiting the context manager, when the object
  is garbage-collected or during interpreter shutdown).
 
+ The *delete* parameter can be used to disable cleanup of the directory tree
+ upon exiting the context. While it may seem unusual for a context manager
+ to disable the action taken when exiting the context, it can be useful during
+ debugging or when you need your cleanup behavior to be conditional based on
+ other logic.
+
  .. audit-event:: tempfile.mkdtemp fullpath tempfile.TemporaryDirectory
 
  .. versionadded:: 3.2
 
  .. versionchanged:: 3.10
  Added *ignore_cleanup_errors* parameter.
 
+ .. versionchanged:: 3.12
+ Added the *delete* parameter.
+
 
 .. function:: mkstemp(suffix=None, prefix=None, dir=None, text=False)
 

Lib/tempfile.py

@@ -850,17 +850,26 @@ class TemporaryDirectory:
  ...
 
  Upon exiting the context, the directory and everything contained
- in it are removed.
+ in it are removed (unless delete=False is passed or an exception
+ is raised during cleanup and ignore_cleanup_errors is not True).
+
+ Optional Arguments:
+ suffix - A str suffix for the directory name. (see mkdtemp)
+ prefix - A str prefix for the directory name. (see mkdtemp)
+ dir - A directory to create this temp dir in. (see mkdtemp)
+ ignore_cleanup_errors - False; ignore exceptions during cleanup?
+ delete - True; whether the directory is automatically deleted.
  """
 
  def __init__(self, suffix=None, prefix=None, dir=None,
- ignore_cleanup_errors=False):
+ ignore_cleanup_errors=False, *, delete=True):
  self.name = mkdtemp(suffix, prefix, dir)
  self._ignore_cleanup_errors = ignore_cleanup_errors
+ self._delete = delete
  self._finalizer = _weakref.finalize(
  self, self._cleanup, self.name,
  warn_message="Implicitly cleaning up {!r}".format(self),
- ignore_errors=self._ignore_cleanup_errors)
+ ignore_errors=self._ignore_cleanup_errors, delete=self._delete)
 
  @classmethod
  def _rmtree(cls, name, ignore_errors=False):
@@ -894,9 +903,10 @@ def resetperms(path):
  _shutil.rmtree(name, onexc=onexc)
 
  @classmethod
- def _cleanup(cls, name, warn_message, ignore_errors=False):
- cls._rmtree(name, ignore_errors=ignore_errors)
- _warnings.warn(warn_message, ResourceWarning)
+ def _cleanup(cls, name, warn_message, ignore_errors=False, delete=True):
+ if delete:
+ cls._rmtree(name, ignore_errors=ignore_errors)
+ _warnings.warn(warn_message, ResourceWarning)
 
  def __repr__(self):
  return "<{} {!r}>".format(self.__class__.__name__, self.name)
@@ -905,7 +915,8 @@ def __enter__(self):
  return self.name
 
  def __exit__(self, exc, value, tb):
- self.cleanup()
+ if self._delete:
+ self.cleanup()
 
  def cleanup(self):
  if self._finalizer.detach() or _os.path.exists(self.name):

Lib/test/test_tempfile.py

@@ -12,6 +12,7 @@
 import types
 import weakref
 import gc
+import shutil
 from unittest import mock
 
 import unittest
@@ -1837,6 +1838,11 @@ def test_flags(self):
  d.cleanup()
  self.assertFalse(os.path.exists(d.name))
 
+ def test_delete_false(self):
+ with tempfile.TemporaryDirectory(delete=False) as working_dir:
+ pass
+ self.assertTrue(os.path.exists(working_dir))
+ shutil.rmtree(working_dir)
 
 if __name__ == "__main__":
  unittest.main()

Misc/NEWS.d/next/Library/2022-12-09-11-21-38.gh-issue-100131.v863yR.rst

@@ -0,0 +1 @@
+Added an optional ``delete`` keyword argument to :class:`tempfile.TemporaryDirectory`.