view mercurial/help/urls.txt @ 35616:706aa203b396

fileset: add a lightweight file filtering language

This patch was inspired by one that Jun Wu authored for the fb-experimental
repo, to avoid using matcher for efficiency[1].  We want a way to specify what
files will be converted to LFS at commit time.  And per discussion, we also want
to specify what files to skip, text diff, or merge in another config option.
The current `lfs.threshold` config option could not satisfy complex needs.  I'm
putting it in a core package because Augie floated the idea of also using it for
narrow and sparse.

Yuya suggested farming out to fileset.parse(), which added support for more
symbols.  The only fileset element not supported here is 'negate'.  (List isn't
supported by filesets either.)  I also changed the 'always' token to the 'all()'
predicate for consistency, and introduced 'none()' to improve readability in a
future tracked file based config.  The extension operator was changed from '.'
to '**', to match how recursive path globs are specified.  Finally, I changed
the path matcher from '/' to 'path:' at Yuya's suggestion, for consistency with
matcher.  Unfortunately, ':' is currently reserved in filesets, so this has to
be quoted to be processed as a string instead of a symbol[2].  We should
probably revisit that, because it's seriously ugly.  But it's only used by an
experimental extension, and I think using a file based config for LFS may drive
some more tweaks, so I'm settling for this for now.

I reserved all of the glob characters in fileset except '.' and '_' for the
extension test because those are likely valid extension characters.

Sample filter settings:

  all()                        # everything
  size(">20MB")                # larger than 20MB
  !**.txt                      # except for .txt files
  **.zip | **.tar.gz | **.7z   # some types of compressed files
  "path:bin"                   # files under "bin" in the project root

[1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017-December/109387.html
[2] https://www.mercurial-scm.org/pipermail/mercurial-devel/2018-January/109729.html

Valid URLs are of the form::

  local/filesystem/path[#revision]
  file://local/filesystem/path[#revision]
  http://[user[:pass]@]host[:port]/[path][#revision]
  https://[user[:pass]@]host[:port]/[path][#revision]
  ssh://[user@]host[:port]/[path][#revision]

Paths in the local filesystem can either point to Mercurial
repositories or to bundle files (as created by :hg:`bundle` or
:hg:`incoming --bundle`). See also :hg:`help paths`.

An optional identifier after # indicates a particular branch, tag, or
changeset to use from the remote repository. See also :hg:`help
revisions`.

Some features, such as pushing to http:// and https:// URLs are only
possible if the feature is explicitly enabled on the remote Mercurial
server.

Note that the security of HTTPS URLs depends on proper configuration of
web.cacerts.

Some notes about using SSH with Mercurial:

- SSH requires an accessible shell account on the destination machine
  and a copy of hg in the remote path or specified with as remotecmd.
- path is relative to the remote user's home directory by default. Use
  an extra slash at the start of a path to specify an absolute path::

    ssh://example.com//tmp/repository

- Mercurial doesn't use its own compression via SSH; the right thing
  to do is to configure it in your ~/.ssh/config, e.g.::

    Host *.mylocalnetwork.example.com
      Compression no
    Host *
      Compression yes

  Alternatively specify "ssh -C" as your ssh command in your
  configuration file or with the --ssh command line option.

These URLs can all be stored in your configuration file with path
aliases under the [paths] section like so::

  [paths]
  alias1 = URL1
  alias2 = URL2
  ...

You can then use the alias for any command that uses a URL (for
example :hg:`pull alias1` will be treated as :hg:`pull URL1`).

Two path aliases are special because they are used as defaults when
you do not provide the URL to a command:

default:
  When you create a repository with hg clone, the clone command saves
  the location of the source repository as the new repository's
  'default' path. This is then used when you omit path from push- and
  pull-like commands (including incoming and outgoing).

default-push:
  The push command will look for a path named 'default-push', and
  prefer it over 'default' if both are defined.