gh-152586: Make tempfile.TemporaryFileWrapper public

Doc/library/tempfile.rst

@@ -14,10 +14,11 @@
 
 This module creates temporary files and directories.  It works on all
 supported platforms. :class:`TemporaryFile`, :class:`NamedTemporaryFile`,
-:class:`TemporaryDirectory`, and :class:`SpooledTemporaryFile` are high-level
-interfaces which provide automatic cleanup and can be used as
-:term:`context managers <context manager>`. :func:`mkstemp` and
-:func:`mkdtemp` are lower-level functions which require manual cleanup.
+:class:`TemporaryFileWrapper`, :class:`TemporaryDirectory`, and
+:class:`SpooledTemporaryFile` are high-level interfaces which provide
+automatic cleanup and can be used as :term:`context managers
+<context manager>`. :func:`mkstemp` and :func:`mkdtemp` are lower-level
+functions which require manual cleanup.
 
 All the user-callable functions and constructors take additional arguments which
 allow direct control over the location and name of temporary files and
@@ -140,6 +141,33 @@ The module defines the following user-callable items:
    .. versionchanged:: 3.12
       Added *delete_on_close* parameter.
 
+.. class:: TemporaryFileWrapper(file, name, delete=True, delete_on_close=True)
+
+   A mutable wrapper returned by :func:`NamedTemporaryFile`. It wraps the
+   underlying file object, delegating attribute access to it, and ensures
+   the temporary file is deleted when appropriate.
+
+   .. attribute:: file
+
+      The underlying :term:`file-like object`.
+
+   .. attribute:: name
+
+      The file name of the temporary file.
+
+   .. method:: close()
+
+      Close the temporary file, possibly deleting it depending on the
+      *delete* and *delete_on_close* arguments passed to
+      :func:`NamedTemporaryFile`.
+
+   .. note::
+
+      ``tempfile._TemporaryFileWrapper`` is kept as a backwards compatible
+      alias for this class.
+
+   .. versionadded:: next
+
 
 .. class:: SpooledTemporaryFile(max_size=0, mode='w+b', buffering=-1, encoding=None, newline=None, suffix=None, prefix=None, dir=None, *, errors=None)
 

Lib/tempfile.py

@@ -31,6 +31,7 @@
     "TMP_MAX", "gettempprefix",            # constants
     "tempdir", "gettempdir",
     "gettempprefixb", "gettempdirb",
+    "TemporaryFileWrapper",
    ]
 
 
@@ -484,7 +485,7 @@ def __del__(self):
             _warnings.warn(self.warn_message, ResourceWarning)
 
 
-class _TemporaryFileWrapper:
+class TemporaryFileWrapper:
     """Temporary file wrapper
 
     This class provides a wrapper around files opened for
@@ -555,6 +556,8 @@ def __iter__(self):
         for line in self.file:
             yield line
 
+_TemporaryFileWrapper = TemporaryFileWrapper
+
 def NamedTemporaryFile(mode='w+b', buffering=-1, encoding=None,
                        newline=None, suffix=None, prefix=None,
                        dir=None, delete=True, *, errors=None,
@@ -607,7 +610,7 @@ def opener(*args):
             raw = getattr(file, 'buffer', file)
             raw = getattr(raw, 'raw', raw)
             raw.name = name
-            return _TemporaryFileWrapper(file, name, delete, delete_on_close)
+            return TemporaryFileWrapper(file, name, delete, delete_on_close)
         except:
             file.close()
             raise

Lib/test/test_tempfile.py

@@ -148,6 +148,7 @@ def test_exports(self):
             "template" : 1,
             "SpooledTemporaryFile" : 1,
             "TemporaryDirectory" : 1,
+            "TemporaryFileWrapper" : 1,
         }
 
         unexp = []
@@ -1141,7 +1142,7 @@ def my_func(dir):
         try:
             with self.assertWarnsRegex(
                 expected_warning=ResourceWarning,
-                expected_regex=r"Implicitly cleaning up <_TemporaryFileWrapper file=.*>",
+                expected_regex=r"Implicitly cleaning up <TemporaryFileWrapper file=.*>",
             ):
                 tmp_name = my_func(dir)
                 support.gc_collect()
@@ -1195,6 +1196,19 @@ def test_unexpected_error(self):
 
     # How to test the mode and bufsize parameters?
 
+class TestTemporaryFileWrapper(BaseTestCase):
+    """Test TemporaryFileWrapper."""
+
+    def test_public_name(self):
+        self.assertIs(tempfile.TemporaryFileWrapper, tempfile._TemporaryFileWrapper)
+
+    def test_in_all(self):
+        self.assertIn("TemporaryFileWrapper", tempfile.__all__)
+
+    def test_is_return_type_of_named_temporary_file(self):
+        with tempfile.NamedTemporaryFile() as f:
+            self.assertIsInstance(f, tempfile.TemporaryFileWrapper)
+
 class TestSpooledTemporaryFile(BaseTestCase):
     """Test SpooledTemporaryFile()."""