view mercurial/help/extensions.txt @ 34065:0e0ac8f09048

extensions: prohibit unicode defaults

If the default value of an option is a unicode string (something
than happen easily when using a 'from __future__ import unicode_literals'),
any value passed on the command line will be ignored because the fancyopts
module only checks for byte strings and not unicode strings.

Changing fancyopts behavior is easy but would make assumptions on how
the python3 port should be done, which is outside the scope of this patch.

The chosen approach is to stop an extension from being loaded when a unicode
default value is detected, with a hint for the developer.

Mercurial has the ability to add new features through the use of
extensions. Extensions may add new commands, add options to
existing commands, change the default behavior of commands, or
implement hooks.

To enable the "foo" extension, either shipped with Mercurial or in the
Python search path, create an entry for it in your configuration file,
like this::

  [extensions]
  foo =

You may also specify the full path to an extension::

  [extensions]
  myfeature = ~/.hgext/myfeature.py

See :hg:`help config` for more information on configuration files.

Extensions are not loaded by default for a variety of reasons:
they can increase startup overhead; they may be meant for advanced
usage only; they may provide potentially dangerous abilities (such
as letting you destroy or modify history); they might not be ready
for prime time; or they may alter some usual behaviors of stock
Mercurial. It is thus up to the user to activate extensions as
needed.

To explicitly disable an extension enabled in a configuration file of
broader scope, prepend its path with !::

  [extensions]
  # disabling extension bar residing in /path/to/extension/bar.py
  bar = !/path/to/extension/bar.py
  # ditto, but no path was supplied for extension baz
  baz = !