help: expand the extensions topic

mercurial/help.py

@@ -1,559 +1,583 b''
 # help.py - help data for mercurial
 #
 # Copyright 2006 Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 import os, sys
 from i18n import _, gettext
 import extensions
 
 
 # borrowed from pydoc
 def pathdirs():
     '''Convert sys.path into a list of absolute, existing, unique paths.'''
     dirs = []
     normdirs = []
     for dir in sys.path:
         dir = os.path.abspath(dir or '.')
         normdir = os.path.normcase(dir)
         if normdir not in normdirs and os.path.isdir(dir):
             dirs.append(dir)
             normdirs.append(normdir)
     return dirs
 
 # loosely inspired by pydoc.source_synopsis()
 # rewritten to handle ''' as well as """
 # and to return the whole text instead of just the synopsis
 def moduledoc(file):
     '''Return the top python documentation for the given file'''
     result = []
 
     line = file.readline()
     while line[:1] == '#' or not line.strip():
         line = file.readline()
         if not line: break
 
     start = line[:3]
     if start == '"""' or start == "'''":
         line = line[3:]
         while line:
             if line.rstrip().endswith(start):
                 line = line.split(start)[0]
                 if line:
                     result.append(line)
                 break
             elif not line:
                 return None # unmatched delimiter
             result.append(line)
             line = file.readline()
     else:
         return None
 
     return ''.join(result)
 
 def additionalextensions():
     '''Find the extensions shipped with Mercurial but not enabled
 
     Returns extensions names and descriptions, and the max name length
     '''
     exts = {}
     maxlength = 0
 
     for dir in filter(os.path.isdir,
                       (os.path.join(pd, 'hgext') for pd in pathdirs())):
         for e in os.listdir(dir):
             if e.endswith('.py'):
                 name = e.rsplit('.', 1)[0]
                 path = os.path.join(dir, e)
             else:
                 name = e
                 path = os.path.join(dir, e, '__init__.py')
 
             if name in exts or name == '__init__' or not os.path.exists(path):
                 continue
 
             try:
                 extensions.find(name)
             except KeyError:
                 pass
             else:
                 continue # enabled extension
 
             try:
                 file = open(path)
             except IOError:
                 continue
             else:
                 doc = moduledoc(file)
                 file.close()
 
             if doc: # extracting localized synopsis
                 exts[name] = gettext(doc).splitlines()[0]
             else:
                 exts[name] = _('(no help text available)')
             if len(name) > maxlength:
                 maxlength = len(name)
 
     return exts, maxlength
 
 def enabledextensions():
     '''Return the list of enabled extensions, and max name length'''
     enabled = list(extensions.extensions())
     exts = {}
     maxlength = 0
 
     if enabled:
         exthelps = []
         for ename, ext in enabled:
             doc = (gettext(ext.__doc__) or _('(no help text available)'))
             ename = ename.split('.')[-1]
             maxlength = max(len(ename), maxlength)
             exts[ename] = doc.splitlines(0)[0].strip()
 
     return exts, maxlength
 
 def extensionslisting(header, exts, maxlength):
     '''Return a text listing of the given extensions'''
     result = ''
 
     if exts:
         result += '\n%s\n\n' % header
         for name, desc in sorted(exts.iteritems()):
             result += ' %s   %s\n' % (name.ljust(maxlength), desc)
 
     return result
 
 def topicextensions():
     doc = _(r'''
-    Mercurial has an extension mechanism for adding new features.
+    Mercurial has a mechanism for adding new features through the
+    use of extensions. Extensions may bring new commands, or new
+    hooks, or change some behaviors of Mercurial.
+
+    Extensions are not loaded by default for a variety of reasons,
+    they may be meant for an advanced usage or provide potentially
+    dangerous commands (eg. mq or rebase allow to rewrite history),
+    they might not be yet ready for prime-time, or they may alter
+    some usual behaviors of stock Mercurial. It is thus up to the
+    user to activate the extensions as needed.
+
+    To enable an extension "foo" which is either shipped with
+    Mercurial or in the Python search path, create an entry for
+    it in your hgrc, like this:
 
-    To enable an extension "foo" bundled with Mercurial, create an
-    entry for it your hgrc, like this:
-    
-       [extensions]
-       foo =
+      [extensions]
+      foo =
+
+    You may also specify the full path where an extension resides:
+
+      [extensions]
+      myfeature = ~/.hgext/myfeature.py
+
+    To explicitly disable an extension which is enabled in an hgrc
+    of broader scope, prepend its path with !:
+
+      [extensions]
+      # disabling extension bar residing in /ext/path
+      hgext.bar = !/path/to/extension/bar.py
+      # ditto, but no path was supplied for extension baz
+      hgext.baz = !
     ''')
 
     exts, maxlength = enabledextensions()
     doc += extensionslisting(_('enabled extensions:'), exts, maxlength)
 
     exts, maxlength = additionalextensions()
     doc += extensionslisting(_('non-enabled extensions:'), exts, maxlength)
 
     return doc
 
 helptable = (
     (["dates"], _("Date Formats"),
      _(r'''
     Some commands allow the user to specify a date, e.g.:
     * backout, commit, import, tag: Specify the commit date.
     * log, revert, update: Select revision(s) by date.
 
     Many date formats are valid. Here are some examples:
 
     "Wed Dec 6 13:18:29 2006" (local timezone assumed)
     "Dec 6 13:18 -0600" (year assumed, time offset provided)
     "Dec 6 13:18 UTC" (UTC and GMT are aliases for +0000)
     "Dec 6" (midnight)
     "13:18" (today assumed)
     "3:39" (3:39AM assumed)
     "3:39pm" (15:39)
     "2006-12-06 13:18:29" (ISO 8601 format)
     "2006-12-6 13:18"
     "2006-12-6"
     "12-6"
     "12/6"
     "12/6/6" (Dec 6 2006)
 
     Lastly, there is Mercurial's internal format:
 
     "1165432709 0" (Wed Dec 6 13:18:29 2006 UTC)
 
     This is the internal representation format for dates. unixtime is
     the number of seconds since the epoch (1970-01-01 00:00 UTC).
     offset is the offset of the local timezone, in seconds west of UTC
     (negative if the timezone is east of UTC).
 
     The log command also accepts date ranges:
 
     "<{datetime}" - at or before a given date/time
     ">{datetime}" - on or after a given date/time
     "{datetime} to {datetime}" - a date range, inclusive
     "-{days}" - within a given number of days of today
     ''')),
 
     (["patterns"], _("File Name Patterns"),
      _(r'''
     Mercurial accepts several notations for identifying one or more
     files at a time.
 
     By default, Mercurial treats filenames as shell-style extended
     glob patterns.
 
     Alternate pattern notations must be specified explicitly.
 
     To use a plain path name without any pattern matching, start it
     with "path:". These path names must completely match starting at
     the current repository root.
 
     To use an extended glob, start a name with "glob:". Globs are
     rooted at the current directory; a glob such as "*.c" will only
     match files in the current directory ending with ".c".
 
     The supported glob syntax extensions are "**" to match any string
     across path separators and "{a,b}" to mean "a or b".
 
     To use a Perl/Python regular expression, start a name with "re:".
     Regexp pattern matching is anchored at the root of the repository.
 
     Plain examples:
 
     path:foo/bar   a name bar in a directory named foo in the root of
                    the repository
     path:path:name a file or directory named "path:name"
 
     Glob examples:
 
     glob:*.c       any name ending in ".c" in the current directory
     *.c            any name ending in ".c" in the current directory
     **.c           any name ending in ".c" in any subdirectory of the
                    current directory including itself.
     foo/*.c        any name ending in ".c" in the directory foo
     foo/**.c       any name ending in ".c" in any subdirectory of foo
                    including itself.
 
     Regexp examples:
 
     re:.*\.c$      any name ending in ".c", anywhere in the repository
 
     ''')),
 
     (['environment', 'env'], _('Environment Variables'),
      _(r'''
 HG::
     Path to the 'hg' executable, automatically passed when running
     hooks, extensions or external tools. If unset or empty, this is
     the hg executable's name if it's frozen, or an executable named
     'hg' (with %PATHEXT% [defaulting to COM/EXE/BAT/CMD] extensions on
     Windows) is searched.
 
 HGEDITOR::
     This is the name of the editor to run when committing. See EDITOR.
 
     (deprecated, use .hgrc)
 
 HGENCODING::
     This overrides the default locale setting detected by Mercurial.
     This setting is used to convert data including usernames,
     changeset descriptions, tag names, and branches. This setting can
     be overridden with the --encoding command-line option.
 
 HGENCODINGMODE::
     This sets Mercurial's behavior for handling unknown characters
     while transcoding user input. The default is "strict", which
     causes Mercurial to abort if it can't map a character. Other
     settings include "replace", which replaces unknown characters, and
     "ignore", which drops them. This setting can be overridden with
     the --encodingmode command-line option.
 
 HGMERGE::
     An executable to use for resolving merge conflicts. The program
     will be executed with three arguments: local file, remote file,
     ancestor file.
 
     (deprecated, use .hgrc)
 
 HGRCPATH::
     A list of files or directories to search for hgrc files. Item
     separator is ":" on Unix, ";" on Windows. If HGRCPATH is not set,
     platform default search path is used. If empty, only the .hg/hgrc
     from the current repository is read.
 
     For each element in HGRCPATH:
     * if it's a directory, all files ending with .rc are added
     * otherwise, the file itself will be added
 
 HGUSER::
     This is the string used as the author of a commit. If not set,
     available values will be considered in this order:
 
     * HGUSER (deprecated)
     * hgrc files from the HGRCPATH
     * EMAIL
     * interactive prompt
     * LOGNAME (with '@hostname' appended)
 
     (deprecated, use .hgrc)
 
 EMAIL::
     May be used as the author of a commit; see HGUSER.
 
 LOGNAME::
     May be used as the author of a commit; see HGUSER.
 
 VISUAL::
     This is the name of the editor to use when committing. See EDITOR.
 
 EDITOR::
     Sometimes Mercurial needs to open a text file in an editor for a
     user to modify, for example when writing commit messages. The
     editor it uses is determined by looking at the environment
     variables HGEDITOR, VISUAL and EDITOR, in that order. The first
     non-empty one is chosen. If all of them are empty, the editor
     defaults to 'vi'.
 
 PYTHONPATH::
     This is used by Python to find imported modules and may need to be
     set appropriately if this Mercurial is not installed system-wide.
     ''')),
 
     (['revs', 'revisions'], _('Specifying Single Revisions'),
      _(r'''
     Mercurial supports several ways to specify individual revisions.
 
     A plain integer is treated as a revision number. Negative integers
     are treated as topological offsets from the tip, with -1 denoting
     the tip. As such, negative numbers are only useful if you've
     memorized your local tree numbers and want to save typing a single
     digit. This editor suggests copy and paste.
 
     A 40-digit hexadecimal string is treated as a unique revision
     identifier.
 
     A hexadecimal string less than 40 characters long is treated as a
     unique revision identifier, and referred to as a short-form
     identifier. A short-form identifier is only valid if it is the
     prefix of exactly one full-length identifier.
 
     Any other string is treated as a tag name, which is a symbolic
     name associated with a revision identifier. Tag names may not
     contain the ":" character.
 
     The reserved name "tip" is a special tag that always identifies
     the most recent revision.
 
     The reserved name "null" indicates the null revision. This is the
     revision of an empty repository, and the parent of revision 0.
 
     The reserved name "." indicates the working directory parent. If
     no working directory is checked out, it is equivalent to null. If
     an uncommitted merge is in progress, "." is the revision of the
     first parent.
     ''')),
 
     (['mrevs', 'multirevs'], _('Specifying Multiple Revisions'),
      _(r'''
     When Mercurial accepts more than one revision, they may be
     specified individually, or provided as a topologically continuous
     range, separated by the ":" character.
 
     The syntax of range notation is [BEGIN]:[END], where BEGIN and END
     are revision identifiers. Both BEGIN and END are optional. If
     BEGIN is not specified, it defaults to revision number 0. If END
     is not specified, it defaults to the tip. The range ":" thus means
     "all revisions".
 
     If BEGIN is greater than END, revisions are treated in reverse
     order.
 
     A range acts as a closed interval. This means that a range of 3:5
     gives 3, 4 and 5. Similarly, a range of 9:6 gives 9, 8, 7, and 6.
     ''')),
 
     (['diffs'], _('Diff Formats'),
      _(r'''
     Mercurial's default format for showing changes between two
     versions of a file is compatible with the unified format of GNU
     diff, which can be used by GNU patch and many other standard
     tools.
 
     While this standard format is often enough, it does not encode the
     following information:
 
      - executable status and other permission bits
      - copy or rename information
      - changes in binary files
      - creation or deletion of empty files
 
     Mercurial also supports the extended diff format from the git VCS
     which addresses these limitations. The git diff format is not
     produced by default because a few widespread tools still do not
     understand this format.
 
     This means that when generating diffs from a Mercurial repository
     (e.g. with "hg export"), you should be careful about things like
     file copies and renames or other things mentioned above, because
     when applying a standard diff to a different repository, this
     extra information is lost. Mercurial's internal operations (like
     push and pull) are not affected by this, because they use an
     internal binary format for communicating changes.
 
     To make Mercurial produce the git extended diff format, use the
     --git option available for many commands, or set 'git = True' in
     the [diff] section of your hgrc. You do not need to set this
     option when importing diffs in this format or using them in the mq
     extension.
     ''')),
     (['templating'], _('Template Usage'),
      _(r'''
     Mercurial allows you to customize output of commands through
     templates. You can either pass in a template from the command
     line, via the --template option, or select an existing
     template-style (--style).
 
     You can customize output for any "log-like" command: log,
     outgoing, incoming, tip, parents, heads and glog.
 
     Three styles are packaged with Mercurial: default (the style used
     when no explicit preference is passed), compact and changelog.
     Usage:
 
         $ hg log -r1 --style changelog
 
     A template is a piece of text, with markup to invoke variable
     expansion:
 
         $ hg log -r1 --template "{node}\n"
         b56ce7b07c52de7d5fd79fb89701ea538af65746
 
     Strings in curly braces are called keywords. The availability of
     keywords depends on the exact context of the templater. These
     keywords are usually available for templating a log-like command:
 
     - author: String. The unmodified author of the changeset.
     - branches: String. The name of the branch on which the changeset
           was committed. Will be empty if the branch name was default.
     - date: Date information. The date when the changeset was committed.
     - desc: String. The text of the changeset description.
     - diffstat: String. Statistics of changes with the following
           format: "modified files: +added/-removed lines"
     - files: List of strings. All files modified, added, or removed by
           this changeset.
     - file_adds: List of strings. Files added by this changeset.
     - file_mods: List of strings. Files modified by this changeset.
     - file_dels: List of strings. Files removed by this changeset.
     - node: String. The changeset identification hash, as a
           40-character hexadecimal string.
     - parents: List of strings. The parents of the changeset.
     - rev: Integer. The repository-local changeset revision number.
     - tags: List of strings. Any tags associated with the changeset.
 
     The "date" keyword does not produce human-readable output. If you
     want to use a date in your output, you can use a filter to process
     it. Filters are functions which return a string based on the input
     variable. You can also use a chain of filters to get the desired
     output:
 
        $ hg tip --template "{date|isodate}\n"
        2008-08-21 18:22 +0000
 
     List of filters:
 
     - addbreaks: Any text. Add an XHTML "<br />" tag before the end of
           every line except the last.
     - age: Date. Returns a human-readable date/time difference between
           the given date/time and the current date/time.
     - basename: Any text. Treats the text as a path, and returns the
           last component of the path after splitting by the path
           separator (ignoring trailing separators). For example,
           "foo/bar/baz" becomes "baz" and "foo/bar//" becomes "bar".
     - stripdir: Treat the text as path and strip a directory level, if
           possible. For example, "foo" and "foo/bar" becomes "foo".
     - date: Date. Returns a date in a Unix date format, including
           the timezone: "Mon Sep 04 15:13:13 2006 0700".
     - domain: Any text. Finds the first string that looks like an
           email address, and extracts just the domain component.
           Example: 'User <[e-mail]>' becomes 'example.com'.
     - email: Any text. Extracts the first string that looks like an
           email address. Example: 'User <[e-mail]>' becomes
           '[e-mail]'.
     - escape: Any text. Replaces the special XML/XHTML characters "&",
           "<" and ">" with XML entities.
     - fill68: Any text. Wraps the text to fit in 68 columns.
     - fill76: Any text. Wraps the text to fit in 76 columns.
     - firstline: Any text. Returns the first line of text.
     - nonempty: Any text. Returns '(none)' if the string is empty.
     - hgdate: Date. Returns the date as a pair of numbers:
           "1157407993 25200" (Unix timestamp, timezone offset).
     - isodate: Date. Returns the date in ISO 8601 format.
     - localdate: Date. Converts a date to local date.
     - obfuscate: Any text. Returns the input text rendered as a
           sequence of XML entities.
     - person: Any text. Returns the text before an email address.
     - rfc822date: Date. Returns a date using the same format used
           in email headers.
     - short: Changeset hash. Returns the short form of a changeset
           hash, i.e. a 12-byte hexadecimal string.
     - shortdate: Date. Returns a date like "2006-09-18".
     - strip: Any text. Strips all leading and trailing whitespace.
     - tabindent: Any text. Returns the text, with every line except
           the first starting with a tab character.
     - urlescape: Any text. Escapes all "special" characters. For
           example, "foo bar" becomes "foo%20bar".
     - user: Any text. Returns the user portion of an email address.
     ''')),
 
     (['urls'], _('URL Paths'),
      _(r'''
     Valid URLs are of the form:
 
       local/filesystem/path (or file://local/filesystem/path)
       http://[user[:pass]@]host[:port]/[path]
       https://[user[:pass]@]host[:port]/[path]
       ssh://[user[:pass]@]host[:port]/[path]
 
     Paths in the local filesystem can either point to Mercurial
     repositories or to bundle files (as created by 'hg bundle' or
     'hg incoming --bundle').
 
     An optional identifier after # indicates a particular branch, tag,
     or changeset to use from the remote repository.
 
     Some features, such as pushing to http:// and https:// URLs are
     only possible if the feature is explicitly enabled on the remote
     Mercurial server.
 
     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 hgrc
       or with the --ssh command line option.
 
     These URLs can all be stored in your hgrc 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' would pull from the 'alias1' path).
 
     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.
     ''')),
     (["extensions"], _("Using additional features"), topicextensions),
 )