gh-50720: Set errno and strerror on URLError wrapping an OSError by vasiliyk · Pull Request #160938 · python/cpython

vasiliyk · 2026-10-30T01:44:18Z

URLError wrapping an OSError such as socket.gaierror always had errno and strerror set to None.

This PR copies errno and strerror from the reason when it is an OSError.
A string reason leaves both attributes None, as before.

Issue: errno and strerror attributes incorrectly set on socket errors wrapped by urllib #50720

read-the-docs-community · 2026-10-30T01:50:14Z

Documentation build overview

📚 cpython-previews | 🛠️ Build #35546919 | 📁 Comparing e10e451 against main (ef1fce0)

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30 files changed · ± 30 modified

± Modified

orsenthil · 2026-10-31T15:56:20Z

        self.reason = reason
        if filename is not None:
            self.filename = filename
+        if isinstance(reason, OSError):


The only question is winerror Should we handle that?
We don't have a great on windows and if winerror will be different than errno for the scenarios that URLError will capture.

Keeping this just as thought. Not a blocker.

Right, winerror stays None on Windows while the wrapped error carries the code. For socket errors it equals errno, but it differs for non-socket errors wrapped by FileHandler.

Should I open a separate improvement issue for it?

If you have a windows system, could you verify it with a some tests?
Exposing winerror gated by system check will be good.

I only have macOS and Linux.

The CI runs the test suite on Windows, so a Windows-only test would be verified there. I can open a follow-up PR that copies winerror behind a platform check, with the test skipped elsewhere.

What do you think?

Yes, sounds good to me.

bedevere-bot · 2026-10-31T17:12:10Z

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot x86 Debian Installed with X 3.x (tierless) has failed when building commit 2cf2dd6.

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Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1244/builds/10167) and take a look at the build logs.
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If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1244/builds/10167

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1575�[0m, in �[35mftp_open�[0m
    fp, retrlen = �[31mfw.retrfile�[0m�[1;31m(file, type)�[0m
                  �[31m~~~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1845�[0m, in �[35mretrfile�[0m
    conn, retrlen = �[31mself.ftp.ntransfercmd�[0m�[1;31m(cmd)�[0m
                    �[31m~~~~~~~~~~~~~~~~~~~~~�[0m�[1;31m^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m359�[0m, in �[35mntransfercmd�[0m
    resp = self.sendcmd(cmd)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m281�[0m, in �[35msendcmd�[0m
    return �[31mself.getresp�[0m�[1;31m()�[0m
           �[31m~~~~~~~~~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m252�[0m, in �[35mgetresp�[0m
    raise error_temp(resp)
�[1;35mftplib.error_temp�[0m: �[35m425 Security: Bad IP connecting.�[0m


Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m381�[0m, in �[35mtest_ftp_no_timeout�[0m
    u = _urlopen_with_retry(self.FTP_HOST, timeout=None)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m32�[0m, in �[35mwrapped�[0m
    return _retry_thrice(func, exc, *args, **kwargs)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m28�[0m, in �[35m_retry_thrice�[0m
    raise last_exc
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m24�[0m, in �[35m_retry_thrice�[0m
    return func(*args, **kwargs)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m187�[0m, in �[35murlopen�[0m
    return �[31mopener.open�[0m�[1;31m(url, data, timeout)�[0m
           �[31m~~~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m489�[0m, in �[35mopen�[0m
    response = self._open(req, data)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m506�[0m, in �[35m_open�[0m
    result = self._call_chain(self.handle_open, protocol, protocol +
                              '_open', req)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m466�[0m, in �[35m_call_chain�[0m
    result = func(*args)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1588�[0m, in �[35mftp_open�[0m
    raise URLError(f"ftp error: {exp}") from exp
�[1;35murllib.error.URLError�[0m: �[35m<urlopen error ftp error: 425 Security: Bad IP connecting.>�[0m


Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1575�[0m, in �[35mftp_open�[0m
    fp, retrlen = �[31mfw.retrfile�[0m�[1;31m(file, type)�[0m
                  �[31m~~~~~~~~~~~�[0m�[1;31m^^^^^^^^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1865�[0m, in �[35mretrfile�[0m
    conn, retrlen = �[31mself.ftp.ntransfercmd�[0m�[1;31m(cmd)�[0m
                    �[31m~~~~~~~~~~~~~~~~~~~~~�[0m�[1;31m^^^^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m359�[0m, in �[35mntransfercmd�[0m
    resp = self.sendcmd(cmd)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m281�[0m, in �[35msendcmd�[0m
    return �[31mself.getresp�[0m�[1;31m()�[0m
           �[31m~~~~~~~~~~~~�[0m�[1;31m^^�[0m
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/ftplib.py"�[0m, line �[35m252�[0m, in �[35mgetresp�[0m
    raise error_temp(resp)
�[1;35mftplib.error_temp�[0m: �[35m425 Security: Bad IP connecting.�[0m


Traceback (most recent call last):
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m286�[0m, in �[35m_test_urls�[0m
    f = urlopen(url, req, support.INTERNET_TIMEOUT)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m32�[0m, in �[35mwrapped�[0m
    return _retry_thrice(func, exc, *args, **kwargs)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m28�[0m, in �[35m_retry_thrice�[0m
    raise last_exc
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/test/test_urllib2net.py"�[0m, line �[35m24�[0m, in �[35m_retry_thrice�[0m
    return func(*args, **kwargs)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m489�[0m, in �[35mopen�[0m
    response = self._open(req, data)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m506�[0m, in �[35m_open�[0m
    result = self._call_chain(self.handle_open, protocol, protocol +
                              '_open', req)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m466�[0m, in �[35m_call_chain�[0m
    result = func(*args)
  File �[35m"/buildbot/buildarea/3.x.ware-debian-x86.installed/build/target/lib/python3.16/urllib/request.py"�[0m, line �[35m1588�[0m, in �[35mftp_open�[0m
    raise URLError(f"ftp error: {exp}") from exp
�[1;35murllib.error.URLError�[0m: �[35m<urlopen error ftp error: 425 Security: Bad IP connecting.>�[0m

orsenthil · 2026-10-31T19:45:57Z

You can take a look at the buildbot page here:
https://buildbot.python.org/#/builders/1244/builds/10167

The buildbot failures are not related.

pythongh-50720: Set errno and strerror on URLError wrapping an OSError

fd2a709

bedevere-app Bot added the awaiting review label Oct 30, 2026

bedevere-app Bot mentioned this pull request Oct 30, 2026

errno and strerror attributes incorrectly set on socket errors wrapped by urllib #50720

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orsenthil reviewed Oct 31, 2026

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Merge branch 'main' into pythongh-50720-urllib

e10e451

orsenthil approved these changes Oct 31, 2026

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bedevere-app Bot added awaiting merge and removed awaiting review labels Oct 31, 2026

orsenthil enabled auto-merge (squash) October 31, 2026 15:58

orsenthil merged commit 2cf2dd6 into python:main Oct 31, 2026
101 of 103 checks passed

bedevere-app Bot removed the awaiting merge label Oct 31, 2026

vasiliyk mentioned this pull request Oct 31, 2026

gh-50720: Copy winerror to URLError on Windows #161047

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gh-50720: Set errno and strerror on URLError wrapping an OSError - #160938

gh-50720: Set errno and strerror on URLError wrapping an OSError#160938
orsenthil merged 2 commits into
python:mainfrom
vasiliyk:gh-50720-urllib

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