Mercurial > hg
changeset 44123:52f8b07ad2f9
debugcommands: move away from line buffered output on binary stream
Line buffering on binary file objects is apparently undefined behavior
in Python and emits a RuntimeWarning on Python 3.8. See
https://bugs.python.org/issue32236.
This commit changes the I/O logging file descriptor from line
buffered to unbuffered to work around this. I'm no fan of
unbuffered I/O for performance reasons. But I don't think it
is an issue here given the nature of the code.
With this change, test-ssh-proto.t now passes on Python 3.8.
Differential Revision: https://phab.mercurial-scm.org/D7948
| author | Gregory Szorc <gregory.szorc@gmail.com> |
|---|---|
| date | Sat, 18 Jan 2020 10:37:14 -0800 |
| parents | bf5a73243cd5 |
| children | d56a2d6f34f0 |
| files | mercurial/debugcommands.py |
| diffstat | 1 files changed, 7 insertions(+), 4 deletions(-) [+] |
line wrap: on
line diff
--- a/mercurial/debugcommands.py Sat Jan 18 10:43:52 2020 -0800 +++ b/mercurial/debugcommands.py Sat Jan 18 10:37:14 2020 -0800 @@ -3218,16 +3218,19 @@ raise error.Abort(_(b'cannot use both --logiofd and --logiofile')) if opts[b'logiofd']: - # Line buffered because output is line based. + # Ideally we would be line buffered. But line buffering in binary + # mode isn't supported and emits a warning in Python 3.8+. Disabling + # buffering could have performance impacts. But since this isn't + # performance critical code, it should be fine. try: - logfh = os.fdopen(int(opts[b'logiofd']), 'ab', 1) + logfh = os.fdopen(int(opts[b'logiofd']), 'ab', 0) except OSError as e: if e.errno != errno.ESPIPE: raise # can't seek a pipe, so `ab` mode fails on py3 - logfh = os.fdopen(int(opts[b'logiofd']), 'wb', 1) + logfh = os.fdopen(int(opts[b'logiofd']), 'wb', 0) elif opts[b'logiofile']: - logfh = open(opts[b'logiofile'], b'ab', 1) + logfh = open(opts[b'logiofile'], b'ab', 0) s = wireprotoserver.sshserver(ui, repo, logfh=logfh) s.serve_forever()