view mercurial/helptext/hg.1.txt @ 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.

====
 hg
====

---------------------------------------
Mercurial source code management system
---------------------------------------

:Author:         Matt Mackall <[e-mail]>
:Organization:   Mercurial
:Manual section: 1
:Manual group:   Mercurial Manual

.. contents::
   :backlinks: top
   :class: htmlonly
   :depth: 1


Synopsis
""""""""
**hg** *command* [*option*]... [*argument*]...

Description
"""""""""""
The **hg** command provides a command line interface to the Mercurial
system.

Command Elements
""""""""""""""""

files...
    indicates one or more filename or relative path filenames; see
    `File Name Patterns`_ for information on pattern matching

path
    indicates a path on the local machine

revision
    indicates a changeset which can be specified as a changeset
    revision number, a tag, or a unique substring of the changeset
    hash value

repository path
    either the pathname of a local repository or the URI of a remote
    repository.

.. include:: hg.1.gendoc.txt

Files
"""""

``/etc/mercurial/hgrc``, ``$HOME/.hgrc``, ``.hg/hgrc``
    This file contains defaults and configuration. Values in
    ``.hg/hgrc`` override those in ``$HOME/.hgrc``, and these override
    settings made in the global ``/etc/mercurial/hgrc`` configuration.
    See |hgrc(5)|_ for details of the contents and format of these
    files.

``.hgignore``
    This file contains regular expressions (one per line) that
    describe file names that should be ignored by **hg**. For details,
    see |hgignore(5)|_.

``.hgsub``
    This file defines the locations of all subrepositories, and
    tells where the subrepository checkouts came from. For details, see
    :hg:`help subrepos`.

``.hgsubstate``
    This file is where Mercurial stores all nested repository states. *NB: This
    file should not be edited manually.*

``.hgtags``
    This file contains changeset hash values and text tag names (one
    of each separated by spaces) that correspond to tagged versions of
    the repository contents. The file content is encoded using UTF-8.

``.hg/last-message.txt``
    This file is used by :hg:`commit` to store a backup of the commit message
    in case the commit fails.

``.hg/localtags``
    This file can be used to define local tags which are not shared among
    repositories. The file format is the same as for ``.hgtags``, but it is
    encoded using the local system encoding.

Some commands (e.g. revert) produce backup files ending in ``.orig``,
if the ``.orig`` file already exists and is not tracked by Mercurial,
it will be overwritten.

Bugs
""""
Probably lots, please post them to the mailing list (see Resources_
below) when you find them.

See Also
""""""""
|hgignore(5)|_, |hgrc(5)|_

Author
""""""
Written by Matt Mackall <[e-mail]>

Resources
"""""""""
Main Web Site: https://mercurial-scm.org/

Source code repository: https://www.mercurial-scm.org/repo/hg

Mailing list: https://www.mercurial-scm.org/mailman/listinfo/mercurial/

Copying
"""""""
Copyright (C) 2005-2020 Matt Mackall.
Free use of this software is granted under the terms of the GNU General
Public License version 2 or any later version.

.. include:: common.txt