Feb 28, 2025 · Feb 12, 2025 · Feb 28, 2025 · Feb 28, 2025 · Feb 12, 2025 · Feb 27, 2025
diff --git a/Lib/gzip.py b/Lib/gzip.py
 import builtins
 import io
 import _compression
 import weakref

 __all__ = ["BadGzipFile", "GzipFile", "open", "compress", "decompress"]

                                             0)
            self._write_mtime = mtime
            self._buffer_size = _WRITE_BUFFER_SIZE
            self._buffer = io.BufferedWriter(_WriteBufferStream(self),
            write_wrap = _WriteBufferStream(weakref.proxy(self))
            self._buffer = io.BufferedWriter(write_wrap,
                                             buffer_size=self._buffer_size)
        else:
            raise ValueError("Invalid mode: {!r}".format(mode))
diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py

 import array
 import functools
 import gc
 import io
 import os
 import struct
 import sys
 import unittest
 from subprocess import PIPE, Popen
 from test.support import catch_unraisable_exception
 from test.support import import_helper
 from test.support import os_helper
 from test.support import _4G, bigmemtest, requires_subprocess
        self.assertEqual(gzip.decompress(data), message * 2)


    def test_refloop_unraisable(self):
        # Ensure a GzipFile referring to a temporary fileobj deletes cleanly.
        # Previously an unraisable exception would occur on close because the
        # fileobj would be closed before the GzipFile as the result of a
        # reference loop. See issue gh-129726
        with catch_unraisable_exception() as cm:
            gzip.GzipFile(fileobj=io.BytesIO(), mode="w")
            gc.collect()
            self.assertIsNone(cm.unraisable)


 class TestOpen(BaseTest):
    def test_binary_modes(self):
        uncompressed = data1 * 50
diff --git a/Misc/NEWS.d/next/Library/2025-02-12-12-38-24.gh-issue-129726.jB0sxu.rst b/Misc/NEWS.d/next/Library/2025-02-12-12-38-24.gh-issue-129726.jB0sxu.rst
 Fix :class:`gzip.GzipFile` raising an unraisable exception during garbage
 collection when referring to a temporary object by breaking the reference
 loop with :mod:`weakref`.
Original file line number	Diff line number	Diff line change
Expand Up		@@ -10,6 +10,7 @@
		import builtins
		import io
		import _compression
		import weakref
Copy link ContributorAuthor cmaloneyFeb 12, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. the ordering of imports here is painful to me, but resisted bringing to PEP8 because this fix needs backporting. Copy link Member vstinnerFeb 27, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Please reformat these imports for PEP 8 :-) I will handle merge conflicts on backports if needed. cmaloney reacted with thumbs up emoji

		__all__ = ["BadGzipFile", "GzipFile", "open", "compress", "decompress"]

Expand DownExpand Up		@@ -226,7 +227,8 @@ def __init__(self, filename=None, mode=None,
		0)
		self._write_mtime = mtime
		self._buffer_size = _WRITE_BUFFER_SIZE
		self._buffer = io.BufferedWriter(_WriteBufferStream(self),
		write_wrap = _WriteBufferStream(weakref.proxy(self))
Copy link Member vstinnerFeb 27, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Would it be possible to modify _WriteBufferStream to use a simpler weakref.ref() to store gzip_file instead? This object is private so we can change its API. Something like: class_WriteBufferStream(io.RawIOBase):"""Minimal object to pass WriteBuffer flushes into GzipFile"""def__init__(self,gzip_file):self.gzip_file=weakref.ref(gzip_file)defwrite(self,data):gzip_file=self.gzip_file()ifgzip_fileisNone:raiseRuntimeError("lost gzip_file")returngzip_file._write_raw(data) cmaloney reacted with eyes emoji Copy link ContributorAuthor cmaloneyFeb 28, 2025 Choose a reason for hiding this comment The reason will be displayed to describe this comment to others.Learn more. Updated to your suggestion here. I Spent a bit of time trying to remove`_WriteBufferStream` andjust use`weakref.proxy`, but getting so`GzipFile.write` has a different`write` function from the underlying`self._buffer: BufferedWriter` (which needs to use`self._write_raw`) led me in a lot of circles. More understandable for things I tried to just keep`_WriteBufferStream`.
		self._buffer = io.BufferedWriter(write_wrap,
		buffer_size=self._buffer_size)
		else:
		raise ValueError("Invalid mode: {!r}".format(mode))
Expand Down
Original file line number	Diff line number	Diff line change
Expand Up		@@ -3,12 +3,14 @@

		import array
		import functools
		import gc
		import io
		import os
		import struct
		import sys
		import unittest
		from subprocess import PIPE, Popen
		from test.support import catch_unraisable_exception
		from test.support import import_helper
		from test.support import os_helper
		from test.support import _4G, bigmemtest, requires_subprocess
Expand DownExpand Up		@@ -859,6 +861,17 @@ def test_write_seek_write(self):
		self.assertEqual(gzip.decompress(data), message * 2)


		def test_refloop_unraisable(self):
		# Ensure a GzipFile referring to a temporary fileobj deletes cleanly.
		# Previously an unraisable exception would occur on close because the
		# fileobj would be closed before the GzipFile as the result of a
		# reference loop. See issue gh-129726
		with catch_unraisable_exception() as cm:
		gzip.GzipFile(fileobj=io.BytesIO(), mode="w")
		gc.collect()
		self.assertIsNone(cm.unraisable)


		class TestOpen(BaseTest):
		def test_binary_modes(self):
		uncompressed = data1 * 50
Expand Down
Original file line number	Diff line number	Diff line change
		@@ -0,0 +1,3 @@
		Fix :class:`gzip.GzipFile` raising an unraisable exception during garbage
		collection when referring to a temporary object by breaking the reference
		loop with :mod:`weakref`.