annotate mercurial/helptext/config.txt @ 45123:1efbfa9b36a7

rebase: consider rewrite.empty-successor configuration

This adds support for the recently added rewrite.empty-successor configuration.

The Mercurial system uses a set of configuration files to control
aspects of its behavior.

Troubleshooting
===============

If you're having problems with your configuration,
:hg:`config --debug` can help you understand what is introducing
a setting into your environment.

See :hg:`help config.syntax` and :hg:`help config.files`
for information about how and where to override things.

Structure
=========

The configuration files use a simple ini-file format. A configuration
file consists of sections, led by a ``[section]`` header and followed
by ``name = value`` entries::

  [ui]
  username = Firstname Lastname <[e-mail]>
  verbose = True

The above entries will be referred to as ``ui.username`` and
``ui.verbose``, respectively. See :hg:`help config.syntax`.

Files
=====

Mercurial reads configuration data from several files, if they exist.
These files do not exist by default and you will have to create the
appropriate configuration files yourself:

Local configuration is put into the per-repository ``<repo>/.hg/hgrc`` file.

Global configuration like the username setting is typically put into:

.. container:: windows

  - ``%USERPROFILE%\mercurial.ini`` (on Windows)

.. container:: unix.plan9

  - ``$HOME/.hgrc`` (on Unix, Plan9)

The names of these files depend on the system on which Mercurial is
installed. ``*.rc`` files from a single directory are read in
alphabetical order, later ones overriding earlier ones. Where multiple
paths are given below, settings from earlier paths override later
ones.

.. container:: verbose.unix

  On Unix, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``$HOME/.hgrc`` (per-user)
  - ``${XDG_CONFIG_HOME:-$HOME/.config}/hg/hgrc`` (per-user)
  - ``<install-root>/etc/mercurial/hgrc`` (per-installation)
  - ``<install-root>/etc/mercurial/hgrc.d/*.rc`` (per-installation)
  - ``/etc/mercurial/hgrc`` (per-system)
  - ``/etc/mercurial/hgrc.d/*.rc`` (per-system)
  - ``<internal>/*.rc`` (defaults)

.. container:: verbose.windows

  On Windows, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``%USERPROFILE%\.hgrc`` (per-user)
  - ``%USERPROFILE%\Mercurial.ini`` (per-user)
  - ``%HOME%\.hgrc`` (per-user)
  - ``%HOME%\Mercurial.ini`` (per-user)
  - ``HKEY_LOCAL_MACHINE\SOFTWARE\Mercurial`` (per-system)
  - ``<install-dir>\hgrc.d\*.rc`` (per-installation)
  - ``<install-dir>\Mercurial.ini`` (per-installation)
  - ``%PROGRAMDATA%\Mercurial\hgrc`` (per-system)
  - ``%PROGRAMDATA%\Mercurial\Mercurial.ini`` (per-system)
  - ``%PROGRAMDATA%\Mercurial\hgrc.d\*.rc`` (per-system)
  - ``<internal>/*.rc`` (defaults)

  .. note::

   The registry key ``HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mercurial``
   is used when running 32-bit Python on 64-bit Windows.

.. container:: verbose.plan9

  On Plan9, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``$home/lib/hgrc`` (per-user)
  - ``<install-root>/lib/mercurial/hgrc`` (per-installation)
  - ``<install-root>/lib/mercurial/hgrc.d/*.rc`` (per-installation)
  - ``/lib/mercurial/hgrc`` (per-system)
  - ``/lib/mercurial/hgrc.d/*.rc`` (per-system)
  - ``<internal>/*.rc`` (defaults)

Per-repository configuration options only apply in a
particular repository. This file is not version-controlled, and
will not get transferred during a "clone" operation. Options in
this file override options in all other configuration files.

.. container:: unix.plan9

  On Plan 9 and Unix, most of this file will be ignored if it doesn't
  belong to a trusted user or to a trusted group. See
  :hg:`help config.trusted` for more details.

Per-user configuration file(s) are for the user running Mercurial.  Options
in these files apply to all Mercurial commands executed by this user in any
directory. Options in these files override per-system and per-installation
options.

Per-installation configuration files are searched for in the
directory where Mercurial is installed. ``<install-root>`` is the
parent directory of the **hg** executable (or symlink) being run.

.. container:: unix.plan9

  For example, if installed in ``/shared/tools/bin/hg``, Mercurial
  will look in ``/shared/tools/etc/mercurial/hgrc``. Options in these
  files apply to all Mercurial commands executed by any user in any
  directory.

Per-installation configuration files are for the system on
which Mercurial is running. Options in these files apply to all
Mercurial commands executed by any user in any directory. Registry
keys contain PATH-like strings, every part of which must reference
a ``Mercurial.ini`` file or be a directory where ``*.rc`` files will
be read.  Mercurial checks each of these locations in the specified
order until one or more configuration files are detected.

Per-system configuration files are for the system on which Mercurial
is running. Options in these files apply to all Mercurial commands
executed by any user in any directory. Options in these files
override per-installation options.

Mercurial comes with some default configuration. The default configuration
files are installed with Mercurial and will be overwritten on upgrades. Default
configuration files should never be edited by users or administrators but can
be overridden in other configuration files. So far the directory only contains
merge tool configuration but packagers can also put other default configuration
there.

Syntax
======

A configuration file consists of sections, led by a ``[section]`` header
and followed by ``name = value`` entries (sometimes called
``configuration keys``)::

    [spam]
    eggs=ham
    green=
       eggs

Each line contains one entry. If the lines that follow are indented,
they are treated as continuations of that entry. Leading whitespace is
removed from values. Empty lines are skipped. Lines beginning with
``#`` or ``;`` are ignored and may be used to provide comments.

Configuration keys can be set multiple times, in which case Mercurial
will use the value that was configured last. As an example::

    [spam]
    eggs=large
    ham=serrano
    eggs=small

This would set the configuration key named ``eggs`` to ``small``.

It is also possible to define a section multiple times. A section can
be redefined on the same and/or on different configuration files. For
example::

    [foo]
    eggs=large
    ham=serrano
    eggs=small

    [bar]
    eggs=ham
    green=
       eggs

    [foo]
    ham=prosciutto
    eggs=medium
    bread=toasted

This would set the ``eggs``, ``ham``, and ``bread`` configuration keys
of the ``foo`` section to ``medium``, ``prosciutto``, and ``toasted``,
respectively. As you can see there only thing that matters is the last
value that was set for each of the configuration keys.

If a configuration key is set multiple times in different
configuration files the final value will depend on the order in which
the different configuration files are read, with settings from earlier
paths overriding later ones as described on the ``Files`` section
above.

A line of the form ``%include file`` will include ``file`` into the
current configuration file. The inclusion is recursive, which means
that included files can include other files. Filenames are relative to
the configuration file in which the ``%include`` directive is found.
Environment variables and ``~user`` constructs are expanded in
``file``. This lets you do something like::

  %include ~/.hgrc.d/$HOST.rc

to include a different configuration file on each computer you use.

A line with ``%unset name`` will remove ``name`` from the current
section, if it has been set previously.

The values are either free-form text strings, lists of text strings,
or Boolean values. Boolean values can be set to true using any of "1",
"yes", "true", or "on" and to false using "0", "no", "false", or "off"
(all case insensitive).

List values are separated by whitespace or comma, except when values are
placed in double quotation marks::

  allow_read = "John Doe, PhD", brian, betty

Quotation marks can be escaped by prefixing them with a backslash. Only
quotation marks at the beginning of a word is counted as a quotation
(e.g., ``foo"bar baz`` is the list of ``foo"bar`` and ``baz``).

Sections
========

This section describes the different sections that may appear in a
Mercurial configuration file, the purpose of each section, its possible
keys, and their possible values.

``alias``
---------

Defines command aliases.

Aliases allow you to define your own commands in terms of other
commands (or aliases), optionally including arguments. Positional
arguments in the form of ``$1``, ``$2``, etc. in the alias definition
are expanded by Mercurial before execution. Positional arguments not
already used by ``$N`` in the definition are put at the end of the
command to be executed.

Alias definitions consist of lines of the form::

    <alias> = <command> [<argument>]...

For example, this definition::

    latest = log --limit 5

creates a new command ``latest`` that shows only the five most recent
changesets. You can define subsequent aliases using earlier ones::

    stable5 = latest -b stable

.. note::

   It is possible to create aliases with the same names as
   existing commands, which will then override the original
   definitions. This is almost always a bad idea!

An alias can start with an exclamation point (``!``) to make it a
shell alias. A shell alias is executed with the shell and will let you
run arbitrary commands. As an example, ::

   echo = !echo $@

will let you do ``hg echo foo`` to have ``foo`` printed in your
terminal. A better example might be::

   purge = !$HG status --no-status --unknown -0 re: | xargs -0 rm -f

which will make ``hg purge`` delete all unknown files in the
repository in the same manner as the purge extension.

Positional arguments like ``$1``, ``$2``, etc. in the alias definition
expand to the command arguments. Unmatched arguments are
removed. ``$0`` expands to the alias name and ``$@`` expands to all
arguments separated by a space. ``"$@"`` (with quotes) expands to all
arguments quoted individually and separated by a space. These expansions
happen before the command is passed to the shell.

Shell aliases are executed in an environment where ``$HG`` expands to
the path of the Mercurial that was used to execute the alias. This is
useful when you want to call further Mercurial commands in a shell
alias, as was done above for the purge alias. In addition,
``$HG_ARGS`` expands to the arguments given to Mercurial. In the ``hg
echo foo`` call above, ``$HG_ARGS`` would expand to ``echo foo``.

.. note::

   Some global configuration options such as ``-R`` are
   processed before shell aliases and will thus not be passed to
   aliases.


``annotate``
------------

Settings used when displaying file annotations. All values are
Booleans and default to False. See :hg:`help config.diff` for
related options for the diff command.

``ignorews``
    Ignore white space when comparing lines.

``ignorewseol``
    Ignore white space at the end of a line when comparing lines.

``ignorewsamount``
    Ignore changes in the amount of white space.

``ignoreblanklines``
    Ignore changes whose lines are all blank.


``auth``
--------

Authentication credentials and other authentication-like configuration
for HTTP connections. This section allows you to store usernames and
passwords for use when logging *into* HTTP servers. See
:hg:`help config.web` if you want to configure *who* can login to
your HTTP server.

The following options apply to all hosts.

``cookiefile``
    Path to a file containing HTTP cookie lines. Cookies matching a
    host will be sent automatically.

    The file format uses the Mozilla cookies.txt format, which defines cookies
    on their own lines. Each line contains 7 fields delimited by the tab
    character (domain, is_domain_cookie, path, is_secure, expires, name,
    value). For more info, do an Internet search for "Netscape cookies.txt
    format."

    Note: the cookies parser does not handle port numbers on domains. You
    will need to remove ports from the domain for the cookie to be recognized.
    This could result in a cookie being disclosed to an unwanted server.

    The cookies file is read-only.

Other options in this section are grouped by name and have the following
format::

    <name>.<argument> = <value>

where ``<name>`` is used to group arguments into authentication
entries. Example::

    foo.prefix = hg.intevation.de/mercurial
    foo.username = foo
    foo.password = bar
    foo.schemes = http https

    bar.prefix = secure.example.org
    bar.key = path/to/file.key
    bar.cert = path/to/file.cert
    bar.schemes = https

Supported arguments:

``prefix``
    Either ``*`` or a URI prefix with or without the scheme part.
    The authentication entry with the longest matching prefix is used
    (where ``*`` matches everything and counts as a match of length
    1). If the prefix doesn't include a scheme, the match is performed
    against the URI with its scheme stripped as well, and the schemes
    argument, q.v., is then subsequently consulted.

``username``
    Optional. Username to authenticate with. If not given, and the
    remote site requires basic or digest authentication, the user will
    be prompted for it. Environment variables are expanded in the
    username letting you do ``foo.username = $USER``. If the URI
    includes a username, only ``[auth]`` entries with a matching
    username or without a username will be considered.

``password``
    Optional. Password to authenticate with. If not given, and the
    remote site requires basic or digest authentication, the user
    will be prompted for it.

``key``
    Optional. PEM encoded client certificate key file. Environment
    variables are expanded in the filename.

``cert``
    Optional. PEM encoded client certificate chain file. Environment
    variables are expanded in the filename.

``schemes``
    Optional. Space separated list of URI schemes to use this
    authentication entry with. Only used if the prefix doesn't include
    a scheme. Supported schemes are http and https. They will match
    static-http and static-https respectively, as well.
    (default: https)

If no suitable authentication entry is found, the user is prompted
for credentials as usual if required by the remote.

``cmdserver``
-------------

Controls command server settings. (ADVANCED)

``message-encodings``
    List of encodings for the ``m`` (message) channel. The first encoding
    supported by the server will be selected and advertised in the hello
    message. This is useful only when ``ui.message-output`` is set to
    ``channel``. Supported encodings are ``cbor``.

``shutdown-on-interrupt``
    If set to false, the server's main loop will continue running after
    SIGINT received. ``runcommand`` requests can still be interrupted by
    SIGINT. Close the write end of the pipe to shut down the server
    process gracefully.
    (default: True)

``color``
---------

Configure the Mercurial color mode. For details about how to define your custom
effect and style see :hg:`help color`.

``mode``
    String: control the method used to output color. One of ``auto``, ``ansi``,
    ``win32``, ``terminfo`` or ``debug``. In auto mode, Mercurial will
    use ANSI mode by default (or win32 mode prior to Windows 10) if it detects a
    terminal. Any invalid value will disable color.

``pagermode``
    String: optional override of ``color.mode`` used with pager.

    On some systems, terminfo mode may cause problems when using
    color with ``less -R`` as a pager program. less with the -R option
    will only display ECMA-48 color codes, and terminfo mode may sometimes
    emit codes that less doesn't understand. You can work around this by
    either using ansi mode (or auto mode), or by using less -r (which will
    pass through all terminal control codes, not just color control
    codes).

    On some systems (such as MSYS in Windows), the terminal may support
    a different color mode than the pager program.

``commands``
------------

``commit.post-status``
    Show status of files in the working directory after successful commit.
    (default: False)

``merge.require-rev``
    Require that the revision to merge the current commit with be specified on
    the command line. If this is enabled and a revision is not specified, the
    command aborts.
    (default: False)

``push.require-revs``
    Require revisions to push be specified using one or more mechanisms such as
    specifying them positionally on the command line, using ``-r``, ``-b``,
    and/or ``-B`` on the command line, or using ``paths.<path>:pushrev`` in the
    configuration. If this is enabled and revisions are not specified, the
    command aborts.
    (default: False)

``resolve.confirm``
    Confirm before performing action if no filename is passed.
    (default: False)

``resolve.explicit-re-merge``
    Require uses of ``hg resolve`` to specify which action it should perform,
    instead of re-merging files by default.
    (default: False)

``resolve.mark-check``
    Determines what level of checking :hg:`resolve --mark` will perform before
    marking files as resolved. Valid values are ``none`, ``warn``, and
    ``abort``. ``warn`` will output a warning listing the file(s) that still
    have conflict markers in them, but will still mark everything resolved.
    ``abort`` will output the same warning but will not mark things as resolved.
    If --all is passed and this is set to ``abort``, only a warning will be
    shown (an error will not be raised).
    (default: ``none``)

``status.relative``
    Make paths in :hg:`status` output relative to the current directory.
    (default: False)

``status.terse``
    Default value for the --terse flag, which condenses status output.
    (default: empty)

``update.check``
    Determines what level of checking :hg:`update` will perform before moving
    to a destination revision. Valid values are ``abort``, ``none``,
    ``linear``, and ``noconflict``. ``abort`` always fails if the working
    directory has uncommitted changes. ``none`` performs no checking, and may
    result in a merge with uncommitted changes. ``linear`` allows any update
    as long as it follows a straight line in the revision history, and may
    trigger a merge with uncommitted changes. ``noconflict`` will allow any
    update which would not trigger a merge with uncommitted changes, if any
    are present.
    (default: ``linear``)

``update.requiredest``
    Require that the user pass a destination when running :hg:`update`.
    For example, :hg:`update .::` will be allowed, but a plain :hg:`update`
    will be disallowed.
    (default: False)

``committemplate``
------------------

``changeset``
    String: configuration in this section is used as the template to
    customize the text shown in the editor when committing.

In addition to pre-defined template keywords, commit log specific one
below can be used for customization:

``extramsg``
    String: Extra message (typically 'Leave message empty to abort
    commit.'). This may be changed by some commands or extensions.

For example, the template configuration below shows as same text as
one shown by default::

    [committemplate]
    changeset = {desc}\n\n
        HG: Enter commit message.  Lines beginning with 'HG:' are removed.
        HG: {extramsg}
        HG: --
        HG: user: {author}\n{ifeq(p2rev, "-1", "",
       "HG: branch merge\n")
       }HG: branch '{branch}'\n{if(activebookmark,
       "HG: bookmark '{activebookmark}'\n")   }{subrepos %
       "HG: subrepo {subrepo}\n"              }{file_adds %
       "HG: added {file}\n"                   }{file_mods %
       "HG: changed {file}\n"                 }{file_dels %
       "HG: removed {file}\n"                 }{if(files, "",
       "HG: no files changed\n")}

``diff()``
    String: show the diff (see :hg:`help templates` for detail)

Sometimes it is helpful to show the diff of the changeset in the editor without
having to prefix 'HG: ' to each line so that highlighting works correctly. For
this, Mercurial provides a special string which will ignore everything below
it::

     HG: ------------------------ >8 ------------------------

For example, the template configuration below will show the diff below the
extra message::

    [committemplate]
    changeset = {desc}\n\n
        HG: Enter commit message.  Lines beginning with 'HG:' are removed.
        HG: {extramsg}
        HG: ------------------------ >8 ------------------------
        HG: Do not touch the line above.
        HG: Everything below will be removed.
        {diff()}

.. note::

   For some problematic encodings (see :hg:`help win32mbcs` for
   detail), this customization should be configured carefully, to
   avoid showing broken characters.

   For example, if a multibyte character ending with backslash (0x5c) is
   followed by the ASCII character 'n' in the customized template,
   the sequence of backslash and 'n' is treated as line-feed unexpectedly
   (and the multibyte character is broken, too).

Customized template is used for commands below (``--edit`` may be
required):

- :hg:`backout`
- :hg:`commit`
- :hg:`fetch` (for merge commit only)
- :hg:`graft`
- :hg:`histedit`
- :hg:`import`
- :hg:`qfold`, :hg:`qnew` and :hg:`qrefresh`
- :hg:`rebase`
- :hg:`shelve`
- :hg:`sign`
- :hg:`tag`
- :hg:`transplant`

Configuring items below instead of ``changeset`` allows showing
customized message only for specific actions, or showing different
messages for each action.

- ``changeset.backout`` for :hg:`backout`
- ``changeset.commit.amend.merge`` for :hg:`commit --amend` on merges
- ``changeset.commit.amend.normal`` for :hg:`commit --amend` on other
- ``changeset.commit.normal.merge`` for :hg:`commit` on merges
- ``changeset.commit.normal.normal`` for :hg:`commit` on other
- ``changeset.fetch`` for :hg:`fetch` (impling merge commit)
- ``changeset.gpg.sign`` for :hg:`sign`
- ``changeset.graft`` for :hg:`graft`
- ``changeset.histedit.edit`` for ``edit`` of :hg:`histedit`
- ``changeset.histedit.fold`` for ``fold`` of :hg:`histedit`
- ``changeset.histedit.mess`` for ``mess`` of :hg:`histedit`
- ``changeset.histedit.pick`` for ``pick`` of :hg:`histedit`
- ``changeset.import.bypass`` for :hg:`import --bypass`
- ``changeset.import.normal.merge`` for :hg:`import` on merges
- ``changeset.import.normal.normal`` for :hg:`import` on other
- ``changeset.mq.qnew`` for :hg:`qnew`
- ``changeset.mq.qfold`` for :hg:`qfold`
- ``changeset.mq.qrefresh`` for :hg:`qrefresh`
- ``changeset.rebase.collapse`` for :hg:`rebase --collapse`
- ``changeset.rebase.merge`` for :hg:`rebase` on merges
- ``changeset.rebase.normal`` for :hg:`rebase` on other
- ``changeset.shelve.shelve`` for :hg:`shelve`
- ``changeset.tag.add`` for :hg:`tag` without ``--remove``
- ``changeset.tag.remove`` for :hg:`tag --remove`
- ``changeset.transplant.merge`` for :hg:`transplant` on merges
- ``changeset.transplant.normal`` for :hg:`transplant` on other

These dot-separated lists of names are treated as hierarchical ones.
For example, ``changeset.tag.remove`` customizes the commit message
only for :hg:`tag --remove`, but ``changeset.tag`` customizes the
commit message for :hg:`tag` regardless of ``--remove`` option.

When the external editor is invoked for a commit, the corresponding
dot-separated list of names without the ``changeset.`` prefix
(e.g. ``commit.normal.normal``) is in the ``HGEDITFORM`` environment
variable.

In this section, items other than ``changeset`` can be referred from
others. For example, the configuration to list committed files up
below can be referred as ``{listupfiles}``::

    [committemplate]
    listupfiles = {file_adds %
       "HG: added {file}\n"     }{file_mods %
       "HG: changed {file}\n"   }{file_dels %
       "HG: removed {file}\n"   }{if(files, "",
       "HG: no files changed\n")}

``decode/encode``
-----------------

Filters for transforming files on checkout/checkin. This would
typically be used for newline processing or other
localization/canonicalization of files.

Filters consist of a filter pattern followed by a filter command.
Filter patterns are globs by default, rooted at the repository root.
For example, to match any file ending in ``.txt`` in the root
directory only, use the pattern ``*.txt``. To match any file ending
in ``.c`` anywhere in the repository, use the pattern ``**.c``.
For each file only the first matching filter applies.

The filter command can start with a specifier, either ``pipe:`` or
``tempfile:``. If no specifier is given, ``pipe:`` is used by default.

A ``pipe:`` command must accept data on stdin and return the transformed
data on stdout.

Pipe example::

  [encode]
  # uncompress gzip files on checkin to improve delta compression
  # note: not necessarily a good idea, just an example
  *.gz = pipe: gunzip

  [decode]
  # recompress gzip files when writing them to the working dir (we
  # can safely omit "pipe:", because it's the default)
  *.gz = gzip

A ``tempfile:`` command is a template. The string ``INFILE`` is replaced
with the name of a temporary file that contains the data to be
filtered by the command. The string ``OUTFILE`` is replaced with the name
of an empty temporary file, where the filtered data must be written by
the command.

.. container:: windows

   .. note::

     The tempfile mechanism is recommended for Windows systems,
     where the standard shell I/O redirection operators often have
     strange effects and may corrupt the contents of your files.

This filter mechanism is used internally by the ``eol`` extension to
translate line ending characters between Windows (CRLF) and Unix (LF)
format. We suggest you use the ``eol`` extension for convenience.


``defaults``
------------

(defaults are deprecated. Don't use them. Use aliases instead.)

Use the ``[defaults]`` section to define command defaults, i.e. the
default options/arguments to pass to the specified commands.

The following example makes :hg:`log` run in verbose mode, and
:hg:`status` show only the modified files, by default::

  [defaults]
  log = -v
  status = -m

The actual commands, instead of their aliases, must be used when
defining command defaults. The command defaults will also be applied
to the aliases of the commands defined.


``diff``
--------

Settings used when displaying diffs. Everything except for ``unified``
is a Boolean and defaults to False. See :hg:`help config.annotate`
for related options for the annotate command.

``git``
    Use git extended diff format.

``nobinary``
    Omit git binary patches.

``nodates``
    Don't include dates in diff headers.

``noprefix``
    Omit 'a/' and 'b/' prefixes from filenames. Ignored in plain mode.

``showfunc``
    Show which function each change is in.

``ignorews``
    Ignore white space when comparing lines.

``ignorewsamount``
    Ignore changes in the amount of white space.

``ignoreblanklines``
    Ignore changes whose lines are all blank.

``unified``
    Number of lines of context to show.

``word-diff``
    Highlight changed words.

``email``
---------

Settings for extensions that send email messages.

``from``
    Optional. Email address to use in "From" header and SMTP envelope
    of outgoing messages.

``to``
    Optional. Comma-separated list of recipients' email addresses.

``cc``
    Optional. Comma-separated list of carbon copy recipients'
    email addresses.

``bcc``
    Optional. Comma-separated list of blind carbon copy recipients'
    email addresses.

``method``
    Optional. Method to use to send email messages. If value is ``smtp``
    (default), use SMTP (see the ``[smtp]`` section for configuration).
    Otherwise, use as name of program to run that acts like sendmail
    (takes ``-f`` option for sender, list of recipients on command line,
    message on stdin). Normally, setting this to ``sendmail`` or
    ``/usr/sbin/sendmail`` is enough to use sendmail to send messages.

``charsets``
    Optional. Comma-separated list of character sets considered
    convenient for recipients. Addresses, headers, and parts not
    containing patches of outgoing messages will be encoded in the
    first character set to which conversion from local encoding
    (``$HGENCODING``, ``ui.fallbackencoding``) succeeds. If correct
    conversion fails, the text in question is sent as is.
    (default: '')

    Order of outgoing email character sets:

    1. ``us-ascii``: always first, regardless of settings
    2. ``email.charsets``: in order given by user
    3. ``ui.fallbackencoding``: if not in email.charsets
    4. ``$HGENCODING``: if not in email.charsets
    5. ``utf-8``: always last, regardless of settings

Email example::

  [email]
  from = Joseph User <[e-mail]>
  method = /usr/sbin/sendmail
  # charsets for western Europeans
  # us-ascii, utf-8 omitted, as they are tried first and last
  charsets = iso-8859-1, iso-8859-15, windows-1252


``extensions``
--------------

Mercurial has an extension mechanism for adding new features. To
enable an extension, create an entry for it in this section.

If you know that the extension is already in Python's search path,
you can give the name of the module, followed by ``=``, with nothing
after the ``=``.

Otherwise, give a name that you choose, followed by ``=``, followed by
the path to the ``.py`` file (including the file name extension) that
defines the extension.

To explicitly disable an extension that is enabled in an hgrc of
broader scope, prepend its path with ``!``, as in ``foo = !/ext/path``
or ``foo = !`` when path is not supplied.

Example for ``~/.hgrc``::

  [extensions]
  # (the churn extension will get loaded from Mercurial's path)
  churn =
  # (this extension will get loaded from the file specified)
  myfeature = ~/.hgext/myfeature.py


``format``
----------

Configuration that controls the repository format. Newer format options are more
powerful, but incompatible with some older versions of Mercurial. Format options
are considered at repository initialization only. You need to make a new clone
for config changes to be taken into account.

For more details about repository format and version compatibility, see
https://www.mercurial-scm.org/wiki/MissingRequirement

``usegeneraldelta``
    Enable or disable the "generaldelta" repository format which improves
    repository compression by allowing "revlog" to store deltas against
    arbitrary revisions instead of the previously stored one. This provides
    significant improvement for repositories with branches.

    Repositories with this on-disk format require Mercurial version 1.9.

    Enabled by default.

``dotencode``
    Enable or disable the "dotencode" repository format which enhances
    the "fncache" repository format (which has to be enabled to use
    dotencode) to avoid issues with filenames starting with "._" on
    Mac OS X and spaces on Windows.

    Repositories with this on-disk format require Mercurial version 1.7.

    Enabled by default.

``usefncache``
    Enable or disable the "fncache" repository format which enhances
    the "store" repository format (which has to be enabled to use
    fncache) to allow longer filenames and avoids using Windows
    reserved names, e.g. "nul".

    Repositories with this on-disk format require Mercurial version 1.1.

    Enabled by default.

``usestore``
    Enable or disable the "store" repository format which improves
    compatibility with systems that fold case or otherwise mangle
    filenames. Disabling this option will allow you to store longer filenames
    in some situations at the expense of compatibility.

    Repositories with this on-disk format require Mercurial version 0.9.4.

    Enabled by default.

``sparse-revlog``
    Enable or disable the ``sparse-revlog`` delta strategy. This format improves
    delta re-use inside revlog. For very branchy repositories, it results in a
    smaller store. For repositories with many revisions, it also helps
    performance (by using shortened delta chains.)

    Repositories with this on-disk format require Mercurial version 4.7

    Enabled by default.

``revlog-compression``
    Compression algorithm used by revlog. Supported values are `zlib` and
    `zstd`. The `zlib` engine is the historical default of Mercurial. `zstd` is
    a newer format that is usually a net win over `zlib`, operating faster at
    better compression rates. Use `zstd` to reduce CPU usage. Multiple values
    can be specified, the first available one will be used.

    On some systems, the Mercurial installation may lack `zstd` support.

    Default is `zlib`.

``bookmarks-in-store``
    Store bookmarks in .hg/store/. This means that bookmarks are shared when
    using `hg share` regardless of the `-B` option.

    Repositories with this on-disk format require Mercurial version 5.1.

    Disabled by default.


``graph``
---------

Web graph view configuration. This section let you change graph
elements display properties by branches, for instance to make the
``default`` branch stand out.

Each line has the following format::

    <branch>.<argument> = <value>

where ``<branch>`` is the name of the branch being
customized. Example::

    [graph]
    # 2px width
    default.width = 2
    # red color
    default.color = FF0000

Supported arguments:

``width``
    Set branch edges width in pixels.

``color``
    Set branch edges color in hexadecimal RGB notation.

``hooks``
---------

Commands or Python functions that get automatically executed by
various actions such as starting or finishing a commit. Multiple
hooks can be run for the same action by appending a suffix to the
action. Overriding a site-wide hook can be done by changing its
value or setting it to an empty string.  Hooks can be prioritized
by adding a prefix of ``priority.`` to the hook name on a new line
and setting the priority. The default priority is 0.

Example ``.hg/hgrc``::

  [hooks]
  # update working directory after adding changesets
  changegroup.update = hg update
  # do not use the site-wide hook
  incoming =
  incoming.email = /my/email/hook
  incoming.autobuild = /my/build/hook
  # force autobuild hook to run before other incoming hooks
  priority.incoming.autobuild = 1

Most hooks are run with environment variables set that give useful
additional information. For each hook below, the environment variables
it is passed are listed with names in the form ``$HG_foo``. The
``$HG_HOOKTYPE`` and ``$HG_HOOKNAME`` variables are set for all hooks.
They contain the type of hook which triggered the run and the full name
of the hook in the config, respectively. In the example above, this will
be ``$HG_HOOKTYPE=incoming`` and ``$HG_HOOKNAME=incoming.email``.

.. container:: windows

  Some basic Unix syntax can be enabled for portability, including ``$VAR``
  and ``${VAR}`` style variables.  A ``~`` followed by ``\`` or ``/`` will
  be expanded to ``%USERPROFILE%`` to simulate a subset of tilde expansion
  on Unix.  To use a literal ``$`` or ``~``, it must be escaped with a back
  slash or inside of a strong quote.  Strong quotes will be replaced by
  double quotes after processing.

  This feature is enabled by adding a prefix of ``tonative.`` to the hook
  name on a new line, and setting it to ``True``.  For example::

    [hooks]
    incoming.autobuild = /my/build/hook
    # enable translation to cmd.exe syntax for autobuild hook
    tonative.incoming.autobuild = True

``changegroup``
  Run after a changegroup has been added via push, pull or unbundle.  The ID of
  the first new changeset is in ``$HG_NODE`` and last is in ``$HG_NODE_LAST``.
  The URL from which changes came is in ``$HG_URL``.

``commit``
  Run after a changeset has been created in the local repository. The ID
  of the newly created changeset is in ``$HG_NODE``. Parent changeset
  IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``incoming``
  Run after a changeset has been pulled, pushed, or unbundled into
  the local repository. The ID of the newly arrived changeset is in
  ``$HG_NODE``. The URL that was source of the changes is in ``$HG_URL``.

``outgoing``
  Run after sending changes from the local repository to another. The ID of
  first changeset sent is in ``$HG_NODE``. The source of operation is in
  ``$HG_SOURCE``. Also see :hg:`help config.hooks.preoutgoing`.

``post-<command>``
  Run after successful invocations of the associated command. The
  contents of the command line are passed as ``$HG_ARGS`` and the result
  code in ``$HG_RESULT``. Parsed command line arguments are passed as
  ``$HG_PATS`` and ``$HG_OPTS``. These contain string representations of
  the python data internally passed to <command>. ``$HG_OPTS`` is a
  dictionary of options (with unspecified options set to their defaults).
  ``$HG_PATS`` is a list of arguments. Hook failure is ignored.

``fail-<command>``
  Run after a failed invocation of an associated command. The contents
  of the command line are passed as ``$HG_ARGS``. Parsed command line
  arguments are passed as ``$HG_PATS`` and ``$HG_OPTS``. These contain
  string representations of the python data internally passed to
  <command>. ``$HG_OPTS`` is a dictionary of options (with unspecified
  options set to their defaults). ``$HG_PATS`` is a list of arguments.
  Hook failure is ignored.

``pre-<command>``
  Run before executing the associated command. The contents of the
  command line are passed as ``$HG_ARGS``. Parsed command line arguments
  are passed as ``$HG_PATS`` and ``$HG_OPTS``. These contain string
  representations of the data internally passed to <command>. ``$HG_OPTS``
  is a dictionary of options (with unspecified options set to their
  defaults). ``$HG_PATS`` is a list of arguments. If the hook returns
  failure, the command doesn't execute and Mercurial returns the failure
  code.

``prechangegroup``
  Run before a changegroup is added via push, pull or unbundle. Exit
  status 0 allows the changegroup to proceed. A non-zero status will
  cause the push, pull or unbundle to fail. The URL from which changes
  will come is in ``$HG_URL``.

``precommit``
  Run before starting a local commit. Exit status 0 allows the
  commit to proceed. A non-zero status will cause the commit to fail.
  Parent changeset IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``prelistkeys``
  Run before listing pushkeys (like bookmarks) in the
  repository. A non-zero status will cause failure. The key namespace is
  in ``$HG_NAMESPACE``.

``preoutgoing``
  Run before collecting changes to send from the local repository to
  another. A non-zero status will cause failure. This lets you prevent
  pull over HTTP or SSH. It can also prevent propagating commits (via
  local pull, push (outbound) or bundle commands), but not completely,
  since you can just copy files instead. The source of operation is in
  ``$HG_SOURCE``. If "serve", the operation is happening on behalf of a remote
  SSH or HTTP repository. If "push", "pull" or "bundle", the operation
  is happening on behalf of a repository on same system.

``prepushkey``
  Run before a pushkey (like a bookmark) is added to the
  repository. A non-zero status will cause the key to be rejected. The
  key namespace is in ``$HG_NAMESPACE``, the key is in ``$HG_KEY``,
  the old value (if any) is in ``$HG_OLD``, and the new value is in
  ``$HG_NEW``.

``pretag``
  Run before creating a tag. Exit status 0 allows the tag to be
  created. A non-zero status will cause the tag to fail. The ID of the
  changeset to tag is in ``$HG_NODE``. The name of tag is in ``$HG_TAG``. The
  tag is local if ``$HG_LOCAL=1``, or in the repository if ``$HG_LOCAL=0``.

``pretxnopen``
  Run before any new repository transaction is open. The reason for the
  transaction will be in ``$HG_TXNNAME``, and a unique identifier for the
  transaction will be in ``HG_TXNID``. A non-zero status will prevent the
  transaction from being opened.

``pretxnclose``
  Run right before the transaction is actually finalized. Any repository change
  will be visible to the hook program. This lets you validate the transaction
  content or change it. Exit status 0 allows the commit to proceed. A non-zero
  status will cause the transaction to be rolled back. The reason for the
  transaction opening will be in ``$HG_TXNNAME``, and a unique identifier for
  the transaction will be in ``HG_TXNID``. The rest of the available data will
  vary according the transaction type. New changesets will add ``$HG_NODE``
  (the ID of the first added changeset), ``$HG_NODE_LAST`` (the ID of the last
  added changeset), ``$HG_URL`` and ``$HG_SOURCE`` variables.  Bookmark and
  phase changes will set ``HG_BOOKMARK_MOVED`` and ``HG_PHASES_MOVED`` to ``1``
  respectively, etc.

``pretxnclose-bookmark``
  Run right before a bookmark change is actually finalized. Any repository
  change will be visible to the hook program. This lets you validate the
  transaction content or change it. Exit status 0 allows the commit to
  proceed. A non-zero status will cause the transaction to be rolled back.
  The name of the bookmark will be available in ``$HG_BOOKMARK``, the new
  bookmark location will be available in ``$HG_NODE`` while the previous
  location will be available in ``$HG_OLDNODE``. In case of a bookmark
  creation ``$HG_OLDNODE`` will be empty. In case of deletion ``$HG_NODE``
  will be empty.
  In addition, the reason for the transaction opening will be in
  ``$HG_TXNNAME``, and a unique identifier for the transaction will be in
  ``HG_TXNID``.

``pretxnclose-phase``
  Run right before a phase change is actually finalized. Any repository change
  will be visible to the hook program. This lets you validate the transaction
  content or change it. Exit status 0 allows the commit to proceed.  A non-zero
  status will cause the transaction to be rolled back. The hook is called
  multiple times, once for each revision affected by a phase change.
  The affected node is available in ``$HG_NODE``, the phase in ``$HG_PHASE``
  while the previous ``$HG_OLDPHASE``. In case of new node, ``$HG_OLDPHASE``
  will be empty.  In addition, the reason for the transaction opening will be in
  ``$HG_TXNNAME``, and a unique identifier for the transaction will be in
  ``HG_TXNID``. The hook is also run for newly added revisions. In this case
  the ``$HG_OLDPHASE`` entry will be empty.

``txnclose``
  Run after any repository transaction has been committed. At this
  point, the transaction can no longer be rolled back. The hook will run
  after the lock is released. See :hg:`help config.hooks.pretxnclose` for
  details about available variables.

``txnclose-bookmark``
  Run after any bookmark change has been committed. At this point, the
  transaction can no longer be rolled back. The hook will run after the lock
  is released. See :hg:`help config.hooks.pretxnclose-bookmark` for details
  about available variables.

``txnclose-phase``
  Run after any phase change has been committed. At this point, the
  transaction can no longer be rolled back. The hook will run after the lock
  is released. See :hg:`help config.hooks.pretxnclose-phase` for details about
  available variables.

``txnabort``
  Run when a transaction is aborted. See :hg:`help config.hooks.pretxnclose`
  for details about available variables.

``pretxnchangegroup``
  Run after a changegroup has been added via push, pull or unbundle, but before
  the transaction has been committed. The changegroup is visible to the hook
  program. This allows validation of incoming changes before accepting them.
  The ID of the first new changeset is in ``$HG_NODE`` and last is in
  ``$HG_NODE_LAST``. Exit status 0 allows the transaction to commit. A non-zero
  status will cause the transaction to be rolled back, and the push, pull or
  unbundle will fail. The URL that was the source of changes is in ``$HG_URL``.

``pretxncommit``
  Run after a changeset has been created, but before the transaction is
  committed. The changeset is visible to the hook program. This allows
  validation of the commit message and changes. Exit status 0 allows the
  commit to proceed. A non-zero status will cause the transaction to
  be rolled back. The ID of the new changeset is in ``$HG_NODE``. The parent
  changeset IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``preupdate``
  Run before updating the working directory. Exit status 0 allows
  the update to proceed. A non-zero status will prevent the update.
  The changeset ID of first new parent is in ``$HG_PARENT1``. If updating to a
  merge, the ID of second new parent is in ``$HG_PARENT2``.

``listkeys``
  Run after listing pushkeys (like bookmarks) in the repository. The
  key namespace is in ``$HG_NAMESPACE``. ``$HG_VALUES`` is a
  dictionary containing the keys and values.

``pushkey``
  Run after a pushkey (like a bookmark) is added to the
  repository. The key namespace is in ``$HG_NAMESPACE``, the key is in
  ``$HG_KEY``, the old value (if any) is in ``$HG_OLD``, and the new
  value is in ``$HG_NEW``.

``tag``
  Run after a tag is created. The ID of the tagged changeset is in ``$HG_NODE``.
  The name of tag is in ``$HG_TAG``. The tag is local if ``$HG_LOCAL=1``, or in
  the repository if ``$HG_LOCAL=0``.

``update``
  Run after updating the working directory. The changeset ID of first
  new parent is in ``$HG_PARENT1``. If updating to a merge, the ID of second new
  parent is in ``$HG_PARENT2``. If the update succeeded, ``$HG_ERROR=0``. If the
  update failed (e.g. because conflicts were not resolved), ``$HG_ERROR=1``.

.. note::

   It is generally better to use standard hooks rather than the
   generic pre- and post- command hooks, as they are guaranteed to be
   called in the appropriate contexts for influencing transactions.
   Also, hooks like "commit" will be called in all contexts that
   generate a commit (e.g. tag) and not just the commit command.

.. note::

   Environment variables with empty values may not be passed to
   hooks on platforms such as Windows. As an example, ``$HG_PARENT2``
   will have an empty value under Unix-like platforms for non-merge
   changesets, while it will not be available at all under Windows.

The syntax for Python hooks is as follows::

  hookname = python:modulename.submodule.callable
  hookname = python:/path/to/python/module.py:callable

Python hooks are run within the Mercurial process. Each hook is
called with at least three keyword arguments: a ui object (keyword
``ui``), a repository object (keyword ``repo``), and a ``hooktype``
keyword that tells what kind of hook is used. Arguments listed as
environment variables above are passed as keyword arguments, with no
``HG_`` prefix, and names in lower case.

If a Python hook returns a "true" value or raises an exception, this
is treated as a failure.


``hostfingerprints``
--------------------

(Deprecated. Use ``[hostsecurity]``'s ``fingerprints`` options instead.)

Fingerprints of the certificates of known HTTPS servers.

A HTTPS connection to a server with a fingerprint configured here will
only succeed if the servers certificate matches the fingerprint.
This is very similar to how ssh known hosts works.

The fingerprint is the SHA-1 hash value of the DER encoded certificate.
Multiple values can be specified (separated by spaces or commas). This can
be used to define both old and new fingerprints while a host transitions
to a new certificate.

The CA chain and web.cacerts is not used for servers with a fingerprint.

For example::

    [hostfingerprints]
    hg.intevation.de = fc:e2:8d:d9:51:cd:cb:c1:4d:18:6b:b7:44:8d:49:72:57:e6:cd:33
    hg.intevation.org = fc:e2:8d:d9:51:cd:cb:c1:4d:18:6b:b7:44:8d:49:72:57:e6:cd:33

``hostsecurity``
----------------

Used to specify global and per-host security settings for connecting to
other machines.

The following options control default behavior for all hosts.

``ciphers``
    Defines the cryptographic ciphers to use for connections.

    Value must be a valid OpenSSL Cipher List Format as documented at
    https://www.openssl.org/docs/manmaster/apps/ciphers.html#CIPHER-LIST-FORMAT.

    This setting is for advanced users only. Setting to incorrect values
    can significantly lower connection security or decrease performance.
    You have been warned.

    This option requires Python 2.7.

``minimumprotocol``
    Defines the minimum channel encryption protocol to use.

    By default, the highest version of TLS supported by both client and server
    is used.

    Allowed values are: ``tls1.0``, ``tls1.1``, ``tls1.2``.

    When running on an old Python version, only ``tls1.0`` is allowed since
    old versions of Python only support up to TLS 1.0.

    When running a Python that supports modern TLS versions, the default is
    ``tls1.1``. ``tls1.0`` can still be used to allow TLS 1.0. However, this
    weakens security and should only be used as a feature of last resort if
    a server does not support TLS 1.1+.

Options in the ``[hostsecurity]`` section can have the form
``hostname``:``setting``. This allows multiple settings to be defined on a
per-host basis.

The following per-host settings can be defined.

``ciphers``
    This behaves like ``ciphers`` as described above except it only applies
    to the host on which it is defined.

``fingerprints``
    A list of hashes of the DER encoded peer/remote certificate. Values have
    the form ``algorithm``:``fingerprint``. e.g.
    ``sha256:c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2``.
    In addition, colons (``:``) can appear in the fingerprint part.

    The following algorithms/prefixes are supported: ``sha1``, ``sha256``,
    ``sha512``.

    Use of ``sha256`` or ``sha512`` is preferred.

    If a fingerprint is specified, the CA chain is not validated for this
    host and Mercurial will require the remote certificate to match one
    of the fingerprints specified. This means if the server updates its
    certificate, Mercurial will abort until a new fingerprint is defined.
    This can provide stronger security than traditional CA-based validation
    at the expense of convenience.

    This option takes precedence over ``verifycertsfile``.

``minimumprotocol``
    This behaves like ``minimumprotocol`` as described above except it
    only applies to the host on which it is defined.

``verifycertsfile``
    Path to file a containing a list of PEM encoded certificates used to
    verify the server certificate. Environment variables and ``~user``
    constructs are expanded in the filename.

    The server certificate or the certificate's certificate authority (CA)
    must match a certificate from this file or certificate verification
    will fail and connections to the server will be refused.

    If defined, only certificates provided by this file will be used:
    ``web.cacerts`` and any system/default certificates will not be
    used.

    This option has no effect if the per-host ``fingerprints`` option
    is set.

    The format of the file is as follows::

        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----
        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----

For example::

    [hostsecurity]
    hg.example.com:fingerprints = sha256:c3ab8ff13720e8ad9047dd39466b3c8974e592c2fa383d4a3960714caef0c4f2
    hg2.example.com:fingerprints = sha1:914f1aff87249c09b6859b88b1906d30756491ca, sha1:fc:e2:8d:d9:51:cd:cb:c1:4d:18:6b:b7:44:8d:49:72:57:e6:cd:33
    hg3.example.com:fingerprints = sha256:9a:b0:dc:e2:75:ad:8a:b7:84:58:e5:1f:07:32:f1:87:e6:bd:24:22:af:b7:ce:8e:9c:b4:10:cf:b9:f4:0e:d2
    foo.example.com:verifycertsfile = /etc/ssl/trusted-ca-certs.pem

To change the default minimum protocol version to TLS 1.2 but to allow TLS 1.1
when connecting to ``hg.example.com``::

    [hostsecurity]
    minimumprotocol = tls1.2
    hg.example.com:minimumprotocol = tls1.1

``http_proxy``
--------------

Used to access web-based Mercurial repositories through a HTTP
proxy.

``host``
    Host name and (optional) port of the proxy server, for example
    "myproxy:8000".

``no``
    Optional. Comma-separated list of host names that should bypass
    the proxy.

``passwd``
    Optional. Password to authenticate with at the proxy server.

``user``
    Optional. User name to authenticate with at the proxy server.

``always``
    Optional. Always use the proxy, even for localhost and any entries
    in ``http_proxy.no``. (default: False)

``http``
----------

Used to configure access to Mercurial repositories via HTTP.

``timeout``
    If set, blocking operations will timeout after that many seconds.
    (default: None)

``merge``
---------

This section specifies behavior during merges and updates.

``checkignored``
   Controls behavior when an ignored file on disk has the same name as a tracked
   file in the changeset being merged or updated to, and has different
   contents. Options are ``abort``, ``warn`` and ``ignore``. With ``abort``,
   abort on such files. With ``warn``, warn on such files and back them up as
   ``.orig``. With ``ignore``, don't print a warning and back them up as
   ``.orig``. (default: ``abort``)

``checkunknown``
   Controls behavior when an unknown file that isn't ignored has the same name
   as a tracked file in the changeset being merged or updated to, and has
   different contents. Similar to ``merge.checkignored``, except for files that
   are not ignored. (default: ``abort``)

``on-failure``
   When set to ``continue`` (the default), the merge process attempts to
   merge all unresolved files using the merge chosen tool, regardless of
   whether previous file merge attempts during the process succeeded or not.
   Setting this to ``prompt`` will prompt after any merge failure continue
   or halt the merge process. Setting this to ``halt`` will automatically
   halt the merge process on any merge tool failure. The merge process
   can be restarted by using the ``resolve`` command. When a merge is
   halted, the repository is left in a normal ``unresolved`` merge state.
   (default: ``continue``)

``strict-capability-check``
   Whether capabilities of internal merge tools are checked strictly
   or not, while examining rules to decide merge tool to be used.
   (default: False)

``merge-patterns``
------------------

This section specifies merge tools to associate with particular file
patterns. Tools matched here will take precedence over the default
merge tool. Patterns are globs by default, rooted at the repository
root.

Example::

  [merge-patterns]
  **.c = kdiff3
  **.jpg = myimgmerge

``merge-tools``
---------------

This section configures external merge tools to use for file-level
merges. This section has likely been preconfigured at install time.
Use :hg:`config merge-tools` to check the existing configuration.
Also see :hg:`help merge-tools` for more details.

Example ``~/.hgrc``::

  [merge-tools]
  # Override stock tool location
  kdiff3.executable = ~/bin/kdiff3
  # Specify command line
  kdiff3.args = $base $local $other -o $output
  # Give higher priority
  kdiff3.priority = 1

  # Changing the priority of preconfigured tool
  meld.priority = 0

  # Disable a preconfigured tool
  vimdiff.disabled = yes

  # Define new tool
  myHtmlTool.args = -m $local $other $base $output
  myHtmlTool.regkey = Software\FooSoftware\HtmlMerge
  myHtmlTool.priority = 1

Supported arguments:

``priority``
  The priority in which to evaluate this tool.
  (default: 0)

``executable``
  Either just the name of the executable or its pathname.

  .. container:: windows

    On Windows, the path can use environment variables with ${ProgramFiles}
    syntax.

  (default: the tool name)

``args``
  The arguments to pass to the tool executable. You can refer to the
  files being merged as well as the output file through these
  variables: ``$base``, ``$local``, ``$other``, ``$output``.

  The meaning of ``$local`` and ``$other`` can vary depending on which action is
  being performed. During an update or merge, ``$local`` represents the original
  state of the file, while ``$other`` represents the commit you are updating to or
  the commit you are merging with. During a rebase, ``$local`` represents the
  destination of the rebase, and ``$other`` represents the commit being rebased.

  Some operations define custom labels to assist with identifying the revisions,
  accessible via ``$labellocal``, ``$labelother``, and ``$labelbase``. If custom
  labels are not available, these will be ``local``, ``other``, and ``base``,
  respectively.
  (default: ``$local $base $other``)

``premerge``
  Attempt to run internal non-interactive 3-way merge tool before
  launching external tool.  Options are ``true``, ``false``, ``keep`` or
  ``keep-merge3``. The ``keep`` option will leave markers in the file if the
  premerge fails. The ``keep-merge3`` will do the same but include information
  about the base of the merge in the marker (see internal :merge3 in
  :hg:`help merge-tools`).
  (default: True)

``binary``
  This tool can merge binary files. (default: False, unless tool
  was selected by file pattern match)

``symlink``
  This tool can merge symlinks. (default: False)

``check``
  A list of merge success-checking options:

  ``changed``
    Ask whether merge was successful when the merged file shows no changes.
  ``conflicts``
    Check whether there are conflicts even though the tool reported success.
  ``prompt``
    Always prompt for merge success, regardless of success reported by tool.

``fixeol``
  Attempt to fix up EOL changes caused by the merge tool.
  (default: False)

``gui``
  This tool requires a graphical interface to run. (default: False)

``mergemarkers``
  Controls whether the labels passed via ``$labellocal``, ``$labelother``, and
  ``$labelbase`` are ``detailed`` (respecting ``mergemarkertemplate``) or
  ``basic``. If ``premerge`` is ``keep`` or ``keep-merge3``, the conflict
  markers generated during premerge will be ``detailed`` if either this option or
  the corresponding option in the ``[ui]`` section is ``detailed``.
  (default: ``basic``)

``mergemarkertemplate``
  This setting can be used to override ``mergemarkertemplate`` from the ``[ui]``
  section on a per-tool basis; this applies to the ``$label``-prefixed variables
  and to the conflict markers that are generated if ``premerge`` is ``keep` or
  ``keep-merge3``. See the corresponding variable in ``[ui]`` for more
  information.

.. container:: windows

  ``regkey``
    Windows registry key which describes install location of this
    tool. Mercurial will search for this key first under
    ``HKEY_CURRENT_USER`` and then under ``HKEY_LOCAL_MACHINE``.
    (default: None)

  ``regkeyalt``
    An alternate Windows registry key to try if the first key is not
    found.  The alternate key uses the same ``regname`` and ``regappend``
    semantics of the primary key.  The most common use for this key
    is to search for 32bit applications on 64bit operating systems.
    (default: None)

  ``regname``
    Name of value to read from specified registry key.
    (default: the unnamed (default) value)

  ``regappend``
    String to append to the value read from the registry, typically
    the executable name of the tool.
    (default: None)

``pager``
---------

Setting used to control when to paginate and with what external tool. See
:hg:`help pager` for details.

``pager``
    Define the external tool used as pager.

    If no pager is set, Mercurial uses the environment variable $PAGER.
    If neither pager.pager, nor $PAGER is set, a default pager will be
    used, typically `less` on Unix and `more` on Windows. Example::

      [pager]
      pager = less -FRX

``ignore``
    List of commands to disable the pager for. Example::

      [pager]
      ignore = version, help, update

``patch``
---------

Settings used when applying patches, for instance through the 'import'
command or with Mercurial Queues extension.

``eol``
    When set to 'strict' patch content and patched files end of lines
    are preserved. When set to ``lf`` or ``crlf``, both files end of
    lines are ignored when patching and the result line endings are
    normalized to either LF (Unix) or CRLF (Windows). When set to
    ``auto``, end of lines are again ignored while patching but line
    endings in patched files are normalized to their original setting
    on a per-file basis. If target file does not exist or has no end
    of line, patch line endings are preserved.
    (default: strict)

``fuzz``
    The number of lines of 'fuzz' to allow when applying patches. This
    controls how much context the patcher is allowed to ignore when
    trying to apply a patch.
    (default: 2)

``paths``
---------

Assigns symbolic names and behavior to repositories.

Options are symbolic names defining the URL or directory that is the
location of the repository. Example::

    [paths]
    my_server = https://example.com/my_repo
    local_path = /home/me/repo

These symbolic names can be used from the command line. To pull
from ``my_server``: :hg:`pull my_server`. To push to ``local_path``:
:hg:`push local_path`.

Options containing colons (``:``) denote sub-options that can influence
behavior for that specific path. Example::

    [paths]
    my_server = https://example.com/my_path
    my_server:pushurl = ssh://example.com/my_path

The following sub-options can be defined:

``pushurl``
   The URL to use for push operations. If not defined, the location
   defined by the path's main entry is used.

``pushrev``
   A revset defining which revisions to push by default.

   When :hg:`push` is executed without a ``-r`` argument, the revset
   defined by this sub-option is evaluated to determine what to push.

   For example, a value of ``.`` will push the working directory's
   revision by default.

   Revsets specifying bookmarks will not result in the bookmark being
   pushed.

The following special named paths exist:

``default``
   The URL or directory to use when no source or remote is specified.

   :hg:`clone` will automatically define this path to the location the
   repository was cloned from.

``default-push``
   (deprecated) The URL or directory for the default :hg:`push` location.
   ``default:pushurl`` should be used instead.

``phases``
----------

Specifies default handling of phases. See :hg:`help phases` for more
information about working with phases.

``publish``
    Controls draft phase behavior when working as a server. When true,
    pushed changesets are set to public in both client and server and
    pulled or cloned changesets are set to public in the client.
    (default: True)

``new-commit``
    Phase of newly-created commits.
    (default: draft)

``checksubrepos``
    Check the phase of the current revision of each subrepository. Allowed
    values are "ignore", "follow" and "abort". For settings other than
    "ignore", the phase of the current revision of each subrepository is
    checked before committing the parent repository. If any of those phases is
    greater than the phase of the parent repository (e.g. if a subrepo is in a
    "secret" phase while the parent repo is in "draft" phase), the commit is
    either aborted (if checksubrepos is set to "abort") or the higher phase is
    used for the parent repository commit (if set to "follow").
    (default: follow)


``profiling``
-------------

Specifies profiling type, format, and file output. Two profilers are
supported: an instrumenting profiler (named ``ls``), and a sampling
profiler (named ``stat``).

In this section description, 'profiling data' stands for the raw data
collected during profiling, while 'profiling report' stands for a
statistical text report generated from the profiling data.

``enabled``
    Enable the profiler.
    (default: false)

    This is equivalent to passing ``--profile`` on the command line.

``type``
    The type of profiler to use.
    (default: stat)

    ``ls``
      Use Python's built-in instrumenting profiler. This profiler
      works on all platforms, but each line number it reports is the
      first line of a function. This restriction makes it difficult to
      identify the expensive parts of a non-trivial function.
    ``stat``
      Use a statistical profiler, statprof. This profiler is most
      useful for profiling commands that run for longer than about 0.1
      seconds.

``format``
    Profiling format.  Specific to the ``ls`` instrumenting profiler.
    (default: text)

    ``text``
      Generate a profiling report. When saving to a file, it should be
      noted that only the report is saved, and the profiling data is
      not kept.
    ``kcachegrind``
      Format profiling data for kcachegrind use: when saving to a
      file, the generated file can directly be loaded into
      kcachegrind.

``statformat``
    Profiling format for the ``stat`` profiler.
    (default: hotpath)

    ``hotpath``
      Show a tree-based display containing the hot path of execution (where
      most time was spent).
    ``bymethod``
      Show a table of methods ordered by how frequently they are active.
    ``byline``
      Show a table of lines in files ordered by how frequently they are active.
    ``json``
      Render profiling data as JSON.

``frequency``
    Sampling frequency.  Specific to the ``stat`` sampling profiler.
    (default: 1000)

``output``
    File path where profiling data or report should be saved. If the
    file exists, it is replaced. (default: None, data is printed on
    stderr)

``sort``
    Sort field.  Specific to the ``ls`` instrumenting profiler.
    One of ``callcount``, ``reccallcount``, ``totaltime`` and
    ``inlinetime``.
    (default: inlinetime)

``time-track``
    Control if the stat profiler track ``cpu`` or ``real`` time.
    (default: ``cpu`` on Windows, otherwise ``real``)

``limit``
    Number of lines to show. Specific to the ``ls`` instrumenting profiler.
    (default: 30)

``nested``
    Show at most this number of lines of drill-down info after each main entry.
    This can help explain the difference between Total and Inline.
    Specific to the ``ls`` instrumenting profiler.
    (default: 0)

``showmin``
    Minimum fraction of samples an entry must have for it to be displayed.
    Can be specified as a float between ``0.0`` and ``1.0`` or can have a
    ``%`` afterwards to allow values up to ``100``. e.g. ``5%``.

    Only used by the ``stat`` profiler.

    For the ``hotpath`` format, default is ``0.05``.
    For the ``chrome`` format, default is ``0.005``.

    The option is unused on other formats.

``showmax``
    Maximum fraction of samples an entry can have before it is ignored in
    display. Values format is the same as ``showmin``.

    Only used by the ``stat`` profiler.

    For the ``chrome`` format, default is ``0.999``.

    The option is unused on other formats.

``showtime``
    Show time taken as absolute durations, in addition to percentages.
    Only used by the ``hotpath`` format.
    (default: true)

``progress``
------------

Mercurial commands can draw progress bars that are as informative as
possible. Some progress bars only offer indeterminate information, while others
have a definite end point.

``debug``
    Whether to print debug info when updating the progress bar. (default: False)

``delay``
    Number of seconds (float) before showing the progress bar. (default: 3)

``changedelay``
    Minimum delay before showing a new topic. When set to less than 3 * refresh,
    that value will be used instead. (default: 1)

``estimateinterval``
    Maximum sampling interval in seconds for speed and estimated time
    calculation. (default: 60)

``refresh``
    Time in seconds between refreshes of the progress bar. (default: 0.1)

``format``
    Format of the progress bar.

    Valid entries for the format field are ``topic``, ``bar``, ``number``,
    ``unit``, ``estimate``, ``speed``, and ``item``. ``item`` defaults to the
    last 20 characters of the item, but this can be changed by adding either
    ``-<num>`` which would take the last num characters, or ``+<num>`` for the
    first num characters.

    (default: topic bar number estimate)

``width``
    If set, the maximum width of the progress information (that is, min(width,
    term width) will be used).

``clear-complete``
    Clear the progress bar after it's done. (default: True)

``disable``
    If true, don't show a progress bar.

``assume-tty``
    If true, ALWAYS show a progress bar, unless disable is given.

``rebase``
----------

``evolution.allowdivergence``
    Default to False, when True allow creating divergence when performing
    rebase of obsolete changesets.

``revsetalias``
---------------

Alias definitions for revsets. See :hg:`help revsets` for details.

``rewrite``
-----------

``backup-bundle``
    Whether to save stripped changesets to a bundle file. (default: True)

``update-timestamp``
    If true, updates the date and time of the changeset to current. It is only
    applicable for `hg amend`, `hg commit --amend` and `hg uncommit` in the
    current version.

``empty-successor``

    Control what happens with empty successors that are the result of rewrite
    operations. If set to ``skip``, the successor is not created. If set to
    ``keep``, the empty successor is created and kept.

    Currently, only the rebase command considers this configuration.
    (EXPERIMENTAL)

``storage``
-----------

Control the strategy Mercurial uses internally to store history. Options in this
category impact performance and repository size.

``revlog.optimize-delta-parent-choice``
    When storing a merge revision, both parents will be equally considered as
    a possible delta base. This results in better delta selection and improved
    revlog compression. This option is enabled by default.

    Turning this option off can result in large increase of repository size for
    repository with many merges.

``revlog.reuse-external-delta-parent``
    Control the order in which delta parents are considered when adding new
    revisions from an external source.
    (typically: apply bundle from `hg pull` or `hg push`).

    New revisions are usually provided as a delta against other revisions. By
    default, Mercurial will try to reuse this delta first, therefore using the
    same "delta parent" as the source. Directly using delta's from the source
    reduces CPU usage and usually speeds up operation. However, in some case,
    the source might have sub-optimal delta bases and forcing their reevaluation
    is useful. For example, pushes from an old client could have sub-optimal
    delta's parent that the server want to optimize. (lack of general delta, bad
    parents, choice, lack of sparse-revlog, etc).

    This option is enabled by default. Turning it off will ensure bad delta
    parent choices from older client do not propagate to this repository, at
    the cost of a small increase in CPU consumption.

    Note: this option only control the order in which delta parents are
    considered.  Even when disabled, the existing delta from the source will be
    reused if the same delta parent is selected.

``revlog.reuse-external-delta``
    Control the reuse of delta from external source.
    (typically: apply bundle from `hg pull` or `hg push`).

    New revisions are usually provided as a delta against another revision. By
    default, Mercurial will not recompute the same delta again, trusting
    externally provided deltas. There have been rare cases of small adjustment
    to the diffing algorithm in the past. So in some rare case, recomputing
    delta provided by ancient clients can provides better results. Disabling
    this option means going through a full delta recomputation for all incoming
    revisions. It means a large increase in CPU usage and will slow operations
    down.

    This option is enabled by default. When disabled, it also disables the
    related ``storage.revlog.reuse-external-delta-parent`` option.

``revlog.zlib.level``
    Zlib compression level used when storing data into the repository. Accepted
    Value range from 1 (lowest compression) to 9 (highest compression). Zlib
    default value is 6.


``revlog.zstd.level``
    zstd compression level used when storing data into the repository. Accepted
    Value range from 1 (lowest compression) to 22 (highest compression).
    (default 3)

``server``
----------

Controls generic server settings.

``bookmarks-pushkey-compat``
    Trigger pushkey hook when being pushed bookmark updates. This config exist
    for compatibility purpose (default to True)

    If you use ``pushkey`` and ``pre-pushkey`` hooks to control bookmark
    movement we recommend you migrate them to ``txnclose-bookmark`` and
    ``pretxnclose-bookmark``.

``compressionengines``
    List of compression engines and their relative priority to advertise
    to clients.

    The order of compression engines determines their priority, the first
    having the highest priority. If a compression engine is not listed
    here, it won't be advertised to clients.

    If not set (the default), built-in defaults are used. Run
    :hg:`debuginstall` to list available compression engines and their
    default wire protocol priority.

    Older Mercurial clients only support zlib compression and this setting
    has no effect for legacy clients.

``uncompressed``
    Whether to allow clients to clone a repository using the
    uncompressed streaming protocol. This transfers about 40% more
    data than a regular clone, but uses less memory and CPU on both
    server and client. Over a LAN (100 Mbps or better) or a very fast
    WAN, an uncompressed streaming clone is a lot faster (~10x) than a
    regular clone. Over most WAN connections (anything slower than
    about 6 Mbps), uncompressed streaming is slower, because of the
    extra data transfer overhead. This mode will also temporarily hold
    the write lock while determining what data to transfer.
    (default: True)

``uncompressedallowsecret``
    Whether to allow stream clones when the repository contains secret
    changesets. (default: False)

``preferuncompressed``
    When set, clients will try to use the uncompressed streaming
    protocol. (default: False)

``disablefullbundle``
    When set, servers will refuse attempts to do pull-based clones.
    If this option is set, ``preferuncompressed`` and/or clone bundles
    are highly recommended. Partial clones will still be allowed.
    (default: False)

``streamunbundle``
    When set, servers will apply data sent from the client directly,
    otherwise it will be written to a temporary file first. This option
    effectively prevents concurrent pushes.

``pullbundle``
    When set, the server will check pullbundle.manifest for bundles
    covering the requested heads and common nodes. The first matching
    entry will be streamed to the client.

    For HTTP transport, the stream will still use zlib compression
    for older clients.

``concurrent-push-mode``
    Level of allowed race condition between two pushing clients.

    - 'strict': push is abort if another client touched the repository
      while the push was preparing.
    - 'check-related': push is only aborted if it affects head that got also
      affected while the push was preparing. (default since 5.4)

    'check-related' only takes effect for compatible clients (version
    4.3 and later). Older clients will use 'strict'.

``validate``
    Whether to validate the completeness of pushed changesets by
    checking that all new file revisions specified in manifests are
    present. (default: False)

``maxhttpheaderlen``
    Instruct HTTP clients not to send request headers longer than this
    many bytes. (default: 1024)

``bundle1``
    Whether to allow clients to push and pull using the legacy bundle1
    exchange format. (default: True)

``bundle1gd``
    Like ``bundle1`` but only used if the repository is using the
    *generaldelta* storage format. (default: True)

``bundle1.push``
    Whether to allow clients to push using the legacy bundle1 exchange
    format. (default: True)

``bundle1gd.push``
    Like ``bundle1.push`` but only used if the repository is using the
    *generaldelta* storage format. (default: True)

``bundle1.pull``
    Whether to allow clients to pull using the legacy bundle1 exchange
    format. (default: True)

``bundle1gd.pull``
    Like ``bundle1.pull`` but only used if the repository is using the
    *generaldelta* storage format. (default: True)

    Large repositories using the *generaldelta* storage format should
    consider setting this option because converting *generaldelta*
    repositories to the exchange format required by the bundle1 data
    format can consume a lot of CPU.

``bundle2.stream``
    Whether to allow clients to pull using the bundle2 streaming protocol.
    (default: True)

``zliblevel``
    Integer between ``-1`` and ``9`` that controls the zlib compression level
    for wire protocol commands that send zlib compressed output (notably the
    commands that send repository history data).

    The default (``-1``) uses the default zlib compression level, which is
    likely equivalent to ``6``. ``0`` means no compression. ``9`` means
    maximum compression.

    Setting this option allows server operators to make trade-offs between
    bandwidth and CPU used. Lowering the compression lowers CPU utilization
    but sends more bytes to clients.

    This option only impacts the HTTP server.

``zstdlevel``
    Integer between ``1`` and ``22`` that controls the zstd compression level
    for wire protocol commands. ``1`` is the minimal amount of compression and
    ``22`` is the highest amount of compression.

    The default (``3``) should be significantly faster than zlib while likely
    delivering better compression ratios.

    This option only impacts the HTTP server.

    See also ``server.zliblevel``.

``view``
    Repository filter used when exchanging revisions with the peer.

    The default view (``served``) excludes secret and hidden changesets.
    Another useful value is ``immutable`` (no draft, secret or hidden
    changesets). (EXPERIMENTAL)

``smtp``
--------

Configuration for extensions that need to send email messages.

``host``
    Host name of mail server, e.g. "mail.example.com".

``port``
    Optional. Port to connect to on mail server. (default: 465 if
    ``tls`` is smtps; 25 otherwise)

``tls``
    Optional. Method to enable TLS when connecting to mail server: starttls,
    smtps or none. (default: none)

``username``
    Optional. User name for authenticating with the SMTP server.
    (default: None)

``password``
    Optional. Password for authenticating with the SMTP server. If not
    specified, interactive sessions will prompt the user for a
    password; non-interactive sessions will fail. (default: None)

``local_hostname``
    Optional. The hostname that the sender can use to identify
    itself to the MTA.


``subpaths``
------------

Subrepository source URLs can go stale if a remote server changes name
or becomes temporarily unavailable. This section lets you define
rewrite rules of the form::

    <pattern> = <replacement>

where ``pattern`` is a regular expression matching a subrepository
source URL and ``replacement`` is the replacement string used to
rewrite it. Groups can be matched in ``pattern`` and referenced in
``replacements``. For instance::

    http://server/(.*)-hg/ = http://hg.server/\1/

rewrites ``http://server/foo-hg/`` into ``http://hg.server/foo/``.

Relative subrepository paths are first made absolute, and the
rewrite rules are then applied on the full (absolute) path. If ``pattern``
doesn't match the full path, an attempt is made to apply it on the
relative path alone. The rules are applied in definition order.

``subrepos``
------------

This section contains options that control the behavior of the
subrepositories feature. See also :hg:`help subrepos`.

Security note: auditing in Mercurial is known to be insufficient to
prevent clone-time code execution with carefully constructed Git
subrepos. It is unknown if a similar detect is present in Subversion
subrepos. Both Git and Subversion subrepos are disabled by default
out of security concerns. These subrepo types can be enabled using
the respective options below.

``allowed``
    Whether subrepositories are allowed in the working directory.

    When false, commands involving subrepositories (like :hg:`update`)
    will fail for all subrepository types.
    (default: true)

``hg:allowed``
    Whether Mercurial subrepositories are allowed in the working
    directory. This option only has an effect if ``subrepos.allowed``
    is true.
    (default: true)

``git:allowed``
    Whether Git subrepositories are allowed in the working directory.
    This option only has an effect if ``subrepos.allowed`` is true.

    See the security note above before enabling Git subrepos.
    (default: false)

``svn:allowed``
    Whether Subversion subrepositories are allowed in the working
    directory. This option only has an effect if ``subrepos.allowed``
    is true.

    See the security note above before enabling Subversion subrepos.
    (default: false)

``templatealias``
-----------------

Alias definitions for templates. See :hg:`help templates` for details.

``templates``
-------------

Use the ``[templates]`` section to define template strings.
See :hg:`help templates` for details.

``trusted``
-----------

Mercurial will not use the settings in the
``.hg/hgrc`` file from a repository if it doesn't belong to a trusted
user or to a trusted group, as various hgrc features allow arbitrary
commands to be run. This issue is often encountered when configuring
hooks or extensions for shared repositories or servers. However,
the web interface will use some safe settings from the ``[web]``
section.

This section specifies what users and groups are trusted. The
current user is always trusted. To trust everybody, list a user or a
group with name ``*``. These settings must be placed in an
*already-trusted file* to take effect, such as ``$HOME/.hgrc`` of the
user or service running Mercurial.

``users``
  Comma-separated list of trusted users.

``groups``
  Comma-separated list of trusted groups.


``ui``
------

User interface controls.

``archivemeta``
    Whether to include the .hg_archival.txt file containing meta data
    (hashes for the repository base and for tip) in archives created
    by the :hg:`archive` command or downloaded via hgweb.
    (default: True)

``askusername``
    Whether to prompt for a username when committing. If True, and
    neither ``$HGUSER`` nor ``$EMAIL`` has been specified, then the user will
    be prompted to enter a username. If no username is entered, the
    default ``USER@HOST`` is used instead.
    (default: False)

``clonebundles``
    Whether the "clone bundles" feature is enabled.

    When enabled, :hg:`clone` may download and apply a server-advertised
    bundle file from a URL instead of using the normal exchange mechanism.

    This can likely result in faster and more reliable clones.

    (default: True)

``clonebundlefallback``
    Whether failure to apply an advertised "clone bundle" from a server
    should result in fallback to a regular clone.

    This is disabled by default because servers advertising "clone
    bundles" often do so to reduce server load. If advertised bundles
    start mass failing and clients automatically fall back to a regular
    clone, this would add significant and unexpected load to the server
    since the server is expecting clone operations to be offloaded to
    pre-generated bundles. Failing fast (the default behavior) ensures
    clients don't overwhelm the server when "clone bundle" application
    fails.

    (default: False)

``clonebundleprefers``
    Defines preferences for which "clone bundles" to use.

    Servers advertising "clone bundles" may advertise multiple available
    bundles. Each bundle may have different attributes, such as the bundle
    type and compression format. This option is used to prefer a particular
    bundle over another.

    The following keys are defined by Mercurial:

    BUNDLESPEC
       A bundle type specifier. These are strings passed to :hg:`bundle -t`.
       e.g. ``gzip-v2`` or ``bzip2-v1``.

    COMPRESSION
       The compression format of the bundle. e.g. ``gzip`` and ``bzip2``.

    Server operators may define custom keys.

    Example values: ``COMPRESSION=bzip2``,
    ``BUNDLESPEC=gzip-v2, COMPRESSION=gzip``.

    By default, the first bundle advertised by the server is used.

``color``
    When to colorize output. Possible value are Boolean ("yes" or "no"), or
    "debug", or "always". (default: "yes"). "yes" will use color whenever it
    seems possible. See :hg:`help color` for details.

``commitsubrepos``
    Whether to commit modified subrepositories when committing the
    parent repository. If False and one subrepository has uncommitted
    changes, abort the commit.
    (default: False)

``debug``
    Print debugging information. (default: False)

``editor``
    The editor to use during a commit. (default: ``$EDITOR`` or ``vi``)

``fallbackencoding``
    Encoding to try if it's not possible to decode the changelog using
    UTF-8. (default: ISO-8859-1)

``graphnodetemplate``
    The template used to print changeset nodes in an ASCII revision graph.
    (default: ``{graphnode}``)

``ignore``
    A file to read per-user ignore patterns from. This file should be
    in the same format as a repository-wide .hgignore file. Filenames
    are relative to the repository root. This option supports hook syntax,
    so if you want to specify multiple ignore files, you can do so by
    setting something like ``ignore.other = ~/.hgignore2``. For details
    of the ignore file format, see the ``hgignore(5)`` man page.

``interactive``
    Allow to prompt the user. (default: True)

``interface``
    Select the default interface for interactive features (default: text).
    Possible values are 'text' and 'curses'.

``interface.chunkselector``
    Select the interface for change recording (e.g. :hg:`commit -i`).
    Possible values are 'text' and 'curses'.
    This config overrides the interface specified by ui.interface.

``large-file-limit``
    Largest file size that gives no memory use warning.
    Possible values are integers or 0 to disable the check.
    (default: 10000000)

``logtemplate``
    Template string for commands that print changesets.

``merge``
    The conflict resolution program to use during a manual merge.
    For more information on merge tools see :hg:`help merge-tools`.
    For configuring merge tools see the ``[merge-tools]`` section.

``mergemarkers``
    Sets the merge conflict marker label styling. The ``detailed``
    style uses the ``mergemarkertemplate`` setting to style the labels.
    The ``basic`` style just uses 'local' and 'other' as the marker label.
    One of ``basic`` or ``detailed``.
    (default: ``basic``)

``mergemarkertemplate``
    The template used to print the commit description next to each conflict
    marker during merge conflicts. See :hg:`help templates` for the template
    format.

    Defaults to showing the hash, tags, branches, bookmarks, author, and
    the first line of the commit description.

    If you use non-ASCII characters in names for tags, branches, bookmarks,
    authors, and/or commit descriptions, you must pay attention to encodings of
    managed files. At template expansion, non-ASCII characters use the encoding
    specified by the ``--encoding`` global option, ``HGENCODING`` or other
    environment variables that govern your locale. If the encoding of the merge
    markers is different from the encoding of the merged files,
    serious problems may occur.

    Can be overridden per-merge-tool, see the ``[merge-tools]`` section.

``message-output``
    Where to write status and error messages. (default: ``stdio``)

    ``channel``
      Use separate channel for structured output. (Command-server only)
    ``stderr``
      Everything to stderr.
    ``stdio``
      Status to stdout, and error to stderr.

``origbackuppath``
    The path to a directory used to store generated .orig files. If the path is
    not a directory, one will be created.  If set, files stored in this
    directory have the same name as the original file and do not have a .orig
    suffix.

``paginate``
  Control the pagination of command output (default: True). See :hg:`help pager`
  for details.

``patch``
    An optional external tool that ``hg import`` and some extensions
    will use for applying patches. By default Mercurial uses an
    internal patch utility. The external tool must work as the common
    Unix ``patch`` program. In particular, it must accept a ``-p``
    argument to strip patch headers, a ``-d`` argument to specify the
    current directory, a file name to patch, and a patch file to take
    from stdin.

    It is possible to specify a patch tool together with extra
    arguments. For example, setting this option to ``patch --merge``
    will use the ``patch`` program with its 2-way merge option.

``portablefilenames``
    Check for portable filenames. Can be ``warn``, ``ignore`` or ``abort``.
    (default: ``warn``)

    ``warn``
      Print a warning message on POSIX platforms, if a file with a non-portable
      filename is added (e.g. a file with a name that can't be created on
      Windows because it contains reserved parts like ``AUX``, reserved
      characters like ``:``, or would cause a case collision with an existing
      file).

    ``ignore``
      Don't print a warning.

    ``abort``
      The command is aborted.

    ``true``
      Alias for ``warn``.

    ``false``
      Alias for ``ignore``.

    .. container:: windows

      On Windows, this configuration option is ignored and the command aborted.

``pre-merge-tool-output-template``
    A template that is printed before executing an external merge tool. This can
    be used to print out additional context that might be useful to have during
    the conflict resolution, such as the description of the various commits
    involved or bookmarks/tags.

    Additional information is available in the ``local`, ``base``, and ``other``
    dicts. For example: ``{local.label}``, ``{base.name}``, or
    ``{other.islink}``.

``quiet``
    Reduce the amount of output printed.
    (default: False)

``relative-paths``
    Prefer relative paths in the UI.

``remotecmd``
    Remote command to use for clone/push/pull operations.
    (default: ``hg``)

``report_untrusted``
    Warn if a ``.hg/hgrc`` file is ignored due to not being owned by a
    trusted user or group.
    (default: True)

``slash``
    (Deprecated. Use ``slashpath`` template filter instead.)

    Display paths using a slash (``/``) as the path separator. This
    only makes a difference on systems where the default path
    separator is not the slash character (e.g. Windows uses the
    backslash character (``\``)).
    (default: False)

``statuscopies``
    Display copies in the status command.

``ssh``
    Command to use for SSH connections. (default: ``ssh``)

``ssherrorhint``
    A hint shown to the user in the case of SSH error (e.g.
    ``Please see http://company/internalwiki/ssh.html``)

``strict``
    Require exact command names, instead of allowing unambiguous
    abbreviations. (default: False)

``style``
    Name of style to use for command output.

``supportcontact``
    A URL where users should report a Mercurial traceback. Use this if you are a
    large organisation with its own Mercurial deployment process and crash
    reports should be addressed to your internal support.

``textwidth``
    Maximum width of help text. A longer line generated by ``hg help`` or
    ``hg subcommand --help`` will be broken after white space to get this
    width or the terminal width, whichever comes first.
    A non-positive value will disable this and the terminal width will be
    used. (default: 78)

``timeout``
    The timeout used when a lock is held (in seconds), a negative value
    means no timeout. (default: 600)

``timeout.warn``
    Time (in seconds) before a warning is printed about held lock. A negative
    value means no warning. (default: 0)

``traceback``
    Mercurial always prints a traceback when an unknown exception
    occurs. Setting this to True will make Mercurial print a traceback
    on all exceptions, even those recognized by Mercurial (such as
    IOError or MemoryError). (default: False)

``tweakdefaults``

    By default Mercurial's behavior changes very little from release
    to release, but over time the recommended config settings
    shift. Enable this config to opt in to get automatic tweaks to
    Mercurial's behavior over time. This config setting will have no
    effect if ``HGPLAIN`` is set or ``HGPLAINEXCEPT`` is set and does
    not include ``tweakdefaults``. (default: False)

    It currently means::

      .. tweakdefaultsmarker

``username``
    The committer of a changeset created when running "commit".
    Typically a person's name and email address, e.g. ``Fred Widget
    <[e-mail]>``. Environment variables in the
    username are expanded.

    (default: ``$EMAIL`` or ``username@hostname``. If the username in
    hgrc is empty, e.g. if the system admin set ``username =`` in the
    system hgrc, it has to be specified manually or in a different
    hgrc file)

``verbose``
    Increase the amount of output printed. (default: False)


``web``
-------

Web interface configuration. The settings in this section apply to
both the builtin webserver (started by :hg:`serve`) and the script you
run through a webserver (``hgweb.cgi`` and the derivatives for FastCGI
and WSGI).

The Mercurial webserver does no authentication (it does not prompt for
usernames and passwords to validate *who* users are), but it does do
authorization (it grants or denies access for *authenticated users*
based on settings in this section). You must either configure your
webserver to do authentication for you, or disable the authorization
checks.

For a quick setup in a trusted environment, e.g., a private LAN, where
you want it to accept pushes from anybody, you can use the following
command line::

    $ hg --config web.allow-push=* --config web.push_ssl=False serve

Note that this will allow anybody to push anything to the server and
that this should not be used for public servers.

The full set of options is:

``accesslog``
    Where to output the access log. (default: stdout)

``address``
    Interface address to bind to. (default: all)

``allow-archive``
    List of archive format (bz2, gz, zip) allowed for downloading.
    (default: empty)

``allowbz2``
    (DEPRECATED) Whether to allow .tar.bz2 downloading of repository
    revisions.
    (default: False)

``allowgz``
    (DEPRECATED) Whether to allow .tar.gz downloading of repository
    revisions.
    (default: False)

``allow-pull``
    Whether to allow pulling from the repository. (default: True)

``allow-push``
    Whether to allow pushing to the repository. If empty or not set,
    pushing is not allowed. If the special value ``*``, any remote
    user can push, including unauthenticated users. Otherwise, the
    remote user must have been authenticated, and the authenticated
    user name must be present in this list. The contents of the
    allow-push list are examined after the deny_push list.

``allow_read``
    If the user has not already been denied repository access due to
    the contents of deny_read, this list determines whether to grant
    repository access to the user. If this list is not empty, and the
    user is unauthenticated or not present in the list, then access is
    denied for the user. If the list is empty or not set, then access
    is permitted to all users by default. Setting allow_read to the
    special value ``*`` is equivalent to it not being set (i.e. access
    is permitted to all users). The contents of the allow_read list are
    examined after the deny_read list.

``allowzip``
    (DEPRECATED) Whether to allow .zip downloading of repository
    revisions. This feature creates temporary files.
    (default: False)

``archivesubrepos``
    Whether to recurse into subrepositories when archiving.
    (default: False)

``baseurl``
    Base URL to use when publishing URLs in other locations, so
    third-party tools like email notification hooks can construct
    URLs. Example: ``http://hgserver/repos/``.

``cacerts``
    Path to file containing a list of PEM encoded certificate
    authority certificates. Environment variables and ``~user``
    constructs are expanded in the filename. If specified on the
    client, then it will verify the identity of remote HTTPS servers
    with these certificates.

    To disable SSL verification temporarily, specify ``--insecure`` from
    command line.

    You can use OpenSSL's CA certificate file if your platform has
    one. On most Linux systems this will be
    ``/etc/ssl/certs/ca-certificates.crt``. Otherwise you will have to
    generate this file manually. The form must be as follows::

        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----
        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----

``cache``
    Whether to support caching in hgweb. (default: True)

``certificate``
    Certificate to use when running :hg:`serve`.

``collapse``
    With ``descend`` enabled, repositories in subdirectories are shown at
    a single level alongside repositories in the current path. With
    ``collapse`` also enabled, repositories residing at a deeper level than
    the current path are grouped behind navigable directory entries that
    lead to the locations of these repositories. In effect, this setting
    collapses each collection of repositories found within a subdirectory
    into a single entry for that subdirectory. (default: False)

``comparisoncontext``
    Number of lines of context to show in side-by-side file comparison. If
    negative or the value ``full``, whole files are shown. (default: 5)

    This setting can be overridden by a ``context`` request parameter to the
    ``comparison`` command, taking the same values.

``contact``
    Name or email address of the person in charge of the repository.
    (default: ui.username or ``$EMAIL`` or "unknown" if unset or empty)

``csp``
    Send a ``Content-Security-Policy`` HTTP header with this value.

    The value may contain a special string ``%nonce%``, which will be replaced
    by a randomly-generated one-time use value. If the value contains
    ``%nonce%``, ``web.cache`` will be disabled, as caching undermines the
    one-time property of the nonce. This nonce will also be inserted into
    ``<script>`` elements containing inline JavaScript.

    Note: lots of HTML content sent by the server is derived from repository
    data. Please consider the potential for malicious repository data to
    "inject" itself into generated HTML content as part of your security
    threat model.

``deny_push``
    Whether to deny pushing to the repository. If empty or not set,
    push is not denied. If the special value ``*``, all remote users are
    denied push. Otherwise, unauthenticated users are all denied, and
    any authenticated user name present in this list is also denied. The
    contents of the deny_push list are examined before the allow-push list.

``deny_read``
    Whether to deny reading/viewing of the repository. If this list is
    not empty, unauthenticated users are all denied, and any
    authenticated user name present in this list is also denied access to
    the repository. If set to the special value ``*``, all remote users
    are denied access (rarely needed ;). If deny_read is empty or not set,
    the determination of repository access depends on the presence and
    content of the allow_read list (see description). If both
    deny_read and allow_read are empty or not set, then access is
    permitted to all users by default. If the repository is being
    served via hgwebdir, denied users will not be able to see it in
    the list of repositories. The contents of the deny_read list have
    priority over (are examined before) the contents of the allow_read
    list.

``descend``
    hgwebdir indexes will not descend into subdirectories. Only repositories
    directly in the current path will be shown (other repositories are still
    available from the index corresponding to their containing path).

``description``
    Textual description of the repository's purpose or contents.
    (default: "unknown")

``encoding``
    Character encoding name. (default: the current locale charset)
    Example: "UTF-8".

``errorlog``
    Where to output the error log. (default: stderr)

``guessmime``
    Control MIME types for raw download of file content.
    Set to True to let hgweb guess the content type from the file
    extension. This will serve HTML files as ``text/html`` and might
    allow cross-site scripting attacks when serving untrusted
    repositories. (default: False)

``hidden``
    Whether to hide the repository in the hgwebdir index.
    (default: False)

``ipv6``
    Whether to use IPv6. (default: False)

``labels``
    List of string *labels* associated with the repository.

    Labels are exposed as a template keyword and can be used to customize
    output. e.g. the ``index`` template can group or filter repositories
    by labels and the ``summary`` template can display additional content
    if a specific label is present.

``logoimg``
    File name of the logo image that some templates display on each page.
    The file name is relative to ``staticurl``. That is, the full path to
    the logo image is "staticurl/logoimg".
    If unset, ``hglogo.png`` will be used.

``logourl``
    Base URL to use for logos. If unset, ``https://mercurial-scm.org/``
    will be used.

``maxchanges``
    Maximum number of changes to list on the changelog. (default: 10)

``maxfiles``
    Maximum number of files to list per changeset. (default: 10)

``maxshortchanges``
    Maximum number of changes to list on the shortlog, graph or filelog
    pages. (default: 60)

``name``
    Repository name to use in the web interface.
    (default: current working directory)

``port``
    Port to listen on. (default: 8000)

``prefix``
    Prefix path to serve from. (default: '' (server root))

``push_ssl``
    Whether to require that inbound pushes be transported over SSL to
    prevent password sniffing. (default: True)

``refreshinterval``
    How frequently directory listings re-scan the filesystem for new
    repositories, in seconds. This is relevant when wildcards are used
    to define paths. Depending on how much filesystem traversal is
    required, refreshing may negatively impact performance.

    Values less than or equal to 0 always refresh.
    (default: 20)

``server-header``
    Value for HTTP ``Server`` response header.

``static``
    Directory where static files are served from.

``staticurl``
    Base URL to use for static files. If unset, static files (e.g. the
    hgicon.png favicon) will be served by the CGI script itself. Use
    this setting to serve them directly with the HTTP server.
    Example: ``http://hgserver/static/``.

``stripes``
    How many lines a "zebra stripe" should span in multi-line output.
    Set to 0 to disable. (default: 1)

``style``
    Which template map style to use. The available options are the names of
    subdirectories in the HTML templates path. (default: ``paper``)
    Example: ``monoblue``.

``templates``
    Where to find the HTML templates. The default path to the HTML templates
    can be obtained from ``hg debuginstall``.

``websub``
----------

Web substitution filter definition. You can use this section to
define a set of regular expression substitution patterns which
let you automatically modify the hgweb server output.

The default hgweb templates only apply these substitution patterns
on the revision description fields. You can apply them anywhere
you want when you create your own templates by adding calls to the
"websub" filter (usually after calling the "escape" filter).

This can be used, for example, to convert issue references to links
to your issue tracker, or to convert "markdown-like" syntax into
HTML (see the examples below).

Each entry in this section names a substitution filter.
The value of each entry defines the substitution expression itself.
The websub expressions follow the old interhg extension syntax,
which in turn imitates the Unix sed replacement syntax::

    patternname = s/SEARCH_REGEX/REPLACE_EXPRESSION/[i]

You can use any separator other than "/". The final "i" is optional
and indicates that the search must be case insensitive.

Examples::

    [websub]
    issues = s|issue(\d+)|<a href="http://bts.example.org/issue\1">issue\1</a>|i
    italic = s/\b_(\S+)_\b/<i>\1<\/i>/
    bold = s/\*\b(\S+)\b\*/<b>\1<\/b>/

``worker``
----------

Parallel master/worker configuration. We currently perform working
directory updates in parallel on Unix-like systems, which greatly
helps performance.

``enabled``
    Whether to enable workers code to be used.
    (default: true)

``numcpus``
    Number of CPUs to use for parallel operations. A zero or
    negative value is treated as ``use the default``.
    (default: 4 or the number of CPUs on the system, whichever is larger)

``backgroundclose``
    Whether to enable closing file handles on background threads during certain
    operations. Some platforms aren't very efficient at closing file
    handles that have been written or appended to. By performing file closing
    on background threads, file write rate can increase substantially.
    (default: true on Windows, false elsewhere)

``backgroundcloseminfilecount``
    Minimum number of files required to trigger background file closing.
    Operations not writing this many files won't start background close
    threads.
    (default: 2048)

``backgroundclosemaxqueue``
    The maximum number of opened file handles waiting to be closed in the
    background. This option only has an effect if ``backgroundclose`` is
    enabled.
    (default: 384)

``backgroundclosethreadcount``
    Number of threads to process background file closes. Only relevant if
    ``backgroundclose`` is enabled.
    (default: 4)