annotate mercurial/helptext/color.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.

Mercurial colorizes output from several commands.

For example, the diff command shows additions in green and deletions
in red, while the status command shows modified files in magenta. Many
other commands have analogous colors. It is possible to customize
these colors.

To enable color (default) whenever possible use::

  [ui]
  color = yes

To disable color use::

  [ui]
  color = no

See :hg:`help config.ui.color` for details.

.. container:: windows

  The default pager on Windows does not support color, so enabling the pager
  will effectively disable color.  See :hg:`help config.ui.paginate` to disable
  the pager.  Alternately, MSYS and Cygwin shells provide `less` as a pager,
  which can be configured to support ANSI color mode.  Windows 10 natively
  supports ANSI color mode.

Mode
====

Mercurial can use various systems to display color. The supported modes are
``ansi``, ``win32``, and ``terminfo``.  See :hg:`help config.color` for details
about how to control the mode.

Effects
=======

Other effects in addition to color, like bold and underlined text, are
also available. By default, the terminfo database is used to find the
terminal codes used to change color and effect.  If terminfo is not
available, then effects are rendered with the ECMA-48 SGR control
function (aka ANSI escape codes).

The available effects in terminfo mode are 'blink', 'bold', 'dim',
'inverse', 'invisible', 'italic', 'standout', and 'underline'; in
ECMA-48 mode, the options are 'bold', 'inverse', 'italic', and
'underline'.  How each is rendered depends on the terminal emulator.
Some may not be available for a given terminal type, and will be
silently ignored.

If the terminfo entry for your terminal is missing codes for an effect
or has the wrong codes, you can add or override those codes in your
configuration::

  [color]
  terminfo.dim = \E[2m

where '\E' is substituted with an escape character.

Labels
======

Text receives color effects depending on the labels that it has. Many
default Mercurial commands emit labelled text. You can also define
your own labels in templates using the label function, see :hg:`help
templates`. A single portion of text may have more than one label. In
that case, effects given to the last label will override any other
effects. This includes the special "none" effect, which nullifies
other effects.

Labels are normally invisible. In order to see these labels and their
position in the text, use the global --color=debug option. The same
anchor text may be associated to multiple labels, e.g.

  [log.changeset changeset.secret|changeset:   22611:6f0a53c8f587]

The following are the default effects for some default labels. Default
effects may be overridden from your configuration file::

  [color]
  status.modified = blue bold underline red_background
  status.added = green bold
  status.removed = red bold blue_background
  status.deleted = cyan bold underline
  status.unknown = magenta bold underline
  status.ignored = black bold

  # 'none' turns off all effects
  status.clean = none
  status.copied = none

  qseries.applied = blue bold underline
  qseries.unapplied = black bold
  qseries.missing = red bold

  diff.diffline = bold
  diff.extended = cyan bold
  diff.file_a = red bold
  diff.file_b = green bold
  diff.hunk = magenta
  diff.deleted = red
  diff.inserted = green
  diff.changed = white
  diff.tab =
  diff.trailingwhitespace = bold red_background

  # Blank so it inherits the style of the surrounding label
  changeset.public =
  changeset.draft =
  changeset.secret =

  resolve.unresolved = red bold
  resolve.resolved = green bold

  bookmarks.active = green

  branches.active = none
  branches.closed = black bold
  branches.current = green
  branches.inactive = none

  tags.normal = green
  tags.local = black bold

  rebase.rebased = blue
  rebase.remaining = red bold

  shelve.age = cyan
  shelve.newest = green bold
  shelve.name = blue bold

  histedit.remaining = red bold

Custom colors
=============

Because there are only eight standard colors, Mercurial allows you
to define color names for other color slots which might be available
for your terminal type, assuming terminfo mode.  For instance::

  color.brightblue = 12
  color.pink = 207
  color.orange = 202

to set 'brightblue' to color slot 12 (useful for 16 color terminals
that have brighter colors defined in the upper eight) and, 'pink' and
'orange' to colors in 256-color xterm's default color cube.  These
defined colors may then be used as any of the pre-defined eight,
including appending '_background' to set the background to that color.