view contrib/chg/chg.1 @ 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.

.\"                                      Hey, EMACS: -*- nroff -*-
.\" First parameter, NAME, should be all caps
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.\" other parameters are allowed: see man(7), man(1)
.TH CHG 1 "March 3, 2013"
.\" Please adjust this date whenever revising the manpage.
.\"
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.SH NAME
chg \- a fast client for Mercurial command server
.SH SYNOPSIS
.B chg
.IR command " [" options "] [" arguments "]..."
.br
.SH DESCRIPTION
The
.B chg
command is the wrapper for
.B hg
command.
It uses the Mercurial command server to reduce start-up overhead.
.SH OPTIONS
This program accepts the same command line syntax as the
.B hg
command. Additionally it accepts the following options.
.TP
.B \-\-kill\-chg\-daemon
Terminate the background command servers.
.SH SEE ALSO
.BR hg (1),
.SH AUTHOR
Written by Yuya Nishihara <[e-mail]>.