mercurial/helptext/hgweb.txt

filemerge: add support for partial conflict resolution by external tool

A common class of merge conflicts is in imports/#includes/etc. It's
relatively easy to write a tool that can resolve these conflicts,
perhaps by naively just unioning the statements and leaving any
cleanup to other tools to do later [1]. Such specialized tools cannot
generally resolve all conflicts in a file, of course. Let's therefore
call them "partial merge tools". Note that the internal simplemerge
algorithm is such a partial merge tool - one that only resolves
trivial "conflicts" where one side is unchanged or both sides change
in the same way.

One can also imagine having smarter language-aware partial tools that
merge the AST. It may be useful for such tools to interactively let
the user resolve any conflicts it can't resolve itself. However,
having the option of implementing it as a partial merge tool means
that the developer doesn't *need* to create a UI for it. Instead, the
user can resolve any remaining conflicts with their regular merge tool
(e.g. `:merge3` or `meld).

We don't currently have a way to let the user define such partial
merge tools. That's what this patch addresses. It lets the user
configure partial merge tools to run. Each tool can be configured to
run only on files matching certain patterns (e.g. "*.py"). The tool
takes three inputs (local, base, other) and resolves conflicts by
updating these in place. For example, let's say the inputs are these:


base:
```
import sys

def main():
  print('Hello')
```

local:
```
import os
import sys

def main():
  print('Hi')
```

other:
```
import re
import sys

def main():
  print('Howdy')
```

A partial merge tool could now resolve the conflicting imports by
replacing the import statements in *all* files by the following
snippet, while leaving the remainder of the files unchanged.

```
import os
import re
import sys
```

As a result, simplemerge and any regular merge tool that runs after
the partial merge tool(s) will consider the imports to be
non-conflicting and will only present the conflict in `main()` to the
user.

Differential Revision: https://phab.mercurial-scm.org/D12356

Mercurial's internal web server, hgweb, can serve either a single
repository, or a tree of repositories. In the second case, repository
paths and global options can be defined using a dedicated
configuration file common to :hg:`serve`, ``hgweb.wsgi``,
``hgweb.cgi`` and ``hgweb.fcgi``.

This file uses the same syntax as other Mercurial configuration files
but recognizes only the following sections:

  - web
  - paths
  - collections

The ``web`` options are thoroughly described in :hg:`help config`.

The ``paths`` section maps URL paths to paths of repositories in the
filesystem. hgweb will not expose the filesystem directly - only
Mercurial repositories can be published and only according to the
configuration.

The left hand side is the path in the URL. Note that hgweb reserves
subpaths like ``rev`` or ``file``, try using different names for
nested repositories to avoid confusing effects.

The right hand side is the path in the filesystem. If the specified
path ends with ``*`` or ``**`` the filesystem will be searched
recursively for repositories below that point.
With ``*`` it will not recurse into the repositories it finds (except for
``.hg/patches``).
With ``**`` it will also search inside repository working directories
and possibly find subrepositories.

In this example::

  [paths]
  /projects/a = /srv/tmprepos/a
  /projects/b = c:/repos/b
  / = /srv/repos/*
  /user/bob = /home/bob/repos/**

- The first two entries make two repositories in different directories
  appear under the same directory in the web interface
- The third entry will publish every Mercurial repository found in
  ``/srv/repos/``, for instance the repository ``/srv/repos/quux/``
  will appear as ``http://server/quux/``
- The fourth entry will publish both ``http://server/user/bob/quux/``
  and ``http://server/user/bob/quux/testsubrepo/``

The ``collections`` section is deprecated and has been superseded by
``paths``.

URLs and Common Arguments
=========================

URLs under each repository have the form ``/{command}[/{arguments}]``
where ``{command}`` represents the name of a command or handler and
``{arguments}`` represents any number of additional URL parameters
to that command.

The web server has a default style associated with it. Styles map to
a collection of named templates. Each template is used to render a
specific piece of data, such as a changeset or diff.

The style for the current request can be overridden two ways. First,
if ``{command}`` contains a hyphen (``-``), the text before the hyphen
defines the style. For example, ``/atom-log`` will render the ``log``
command handler with the ``atom`` style. The second way to set the
style is with the ``style`` query string argument. For example,
``/log?style=atom``. The hyphenated URL parameter is preferred.

Not all templates are available for all styles. Attempting to use
a style that doesn't have all templates defined may result in an error
rendering the page.

Many commands take a ``{revision}`` URL parameter. This defines the
changeset to operate on. This is commonly specified as the short,
12 digit hexadecimal abbreviation for the full 40 character unique
revision identifier. However, any value described by
:hg:`help revisions` typically works.

Commands and URLs
=================

The following web commands and their URLs are available:

  .. webcommandsmarker