view hgext/amend.py @ 45095:8e04607023e5

procutil: ensure that procutil.std{out,err}.write() writes all bytes

Python 3 offers different kind of streams and it’s not guaranteed for all of
them that calling write() writes all bytes.

When Python is started in unbuffered mode, sys.std{out,err}.buffer are
instances of io.FileIO, whose write() can write less bytes for
platform-specific reasons (e.g. Linux has a 0x7ffff000 bytes maximum and could
write less if interrupted by a signal; when writing to Windows consoles, it’s
limited to 32767 bytes to avoid the "not enough space" error). This can lead to
silent loss of data, both when using sys.std{out,err}.buffer (which may in fact
not be a buffered stream) and when using the text streams sys.std{out,err}
(I’ve created a CPython bug report for that:
https://bugs.python.org/issue41221).

Python may fix the problem at some point. For now, we implement our own wrapper
for procutil.std{out,err} that calls the raw stream’s write() method until all
bytes have been written. We don’t use sys.std{out,err} for larger writes, so I
think it’s not worth the effort to patch them.

# amend.py - provide the amend command
#
# Copyright 2017 Facebook, Inc.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
"""provide the amend command (EXPERIMENTAL)

This extension provides an ``amend`` command that is similar to
``commit --amend`` but does not prompt an editor.
"""

from __future__ import absolute_import

from mercurial.i18n import _
from mercurial import (
    cmdutil,
    commands,
    pycompat,
    registrar,
)

# Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
# extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
# be specifying the version(s) of Mercurial they are tested with, or
# leave the attribute unspecified.
testedwith = b'ships-with-hg-core'

cmdtable = {}
command = registrar.command(cmdtable)


@command(
    b'amend',
    [
        (
            b'A',
            b'addremove',
            None,
            _(b'mark new/missing files as added/removed before committing'),
        ),
        (b'e', b'edit', None, _(b'invoke editor on commit messages')),
        (b'i', b'interactive', None, _(b'use interactive mode')),
        (
            b'',
            b'close-branch',
            None,
            _(b'mark a branch as closed, hiding it from the branch list'),
        ),
        (b's', b'secret', None, _(b'use the secret phase for committing')),
        (b'n', b'note', b'', _(b'store a note on the amend')),
    ]
    + cmdutil.walkopts
    + cmdutil.commitopts
    + cmdutil.commitopts2
    + cmdutil.commitopts3,
    _(b'[OPTION]... [FILE]...'),
    helpcategory=command.CATEGORY_COMMITTING,
    inferrepo=True,
)
def amend(ui, repo, *pats, **opts):
    """amend the working copy parent with all or specified outstanding changes

    Similar to :hg:`commit --amend`, but reuse the commit message without
    invoking editor, unless ``--edit`` was set.

    See :hg:`help commit` for more details.
    """
    opts = pycompat.byteskwargs(opts)
    cmdutil.checknotesize(ui, opts)

    with repo.wlock(), repo.lock():
        if not opts.get(b'logfile'):
            opts[b'message'] = opts.get(b'message') or repo[b'.'].description()
        opts[b'amend'] = True
        return commands._docommit(ui, repo, *pats, **pycompat.strkwargs(opts))