acl: make sure the extensions is enabled when the acl-hooks run

The acl extension is usually setup through hooks and never directly activated.
This means the config item declared in the extension are not loaded.
We add the necessary logic to make sure the extensions are loaded before the hook
run.

hgext/acl.py

@@ -1,362 +1,379 b''
 # acl.py - changeset access control for mercurial
 #
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 '''hooks for controlling repository access
 
 This hook makes it possible to allow or deny write access to given
 branches and paths of a repository when receiving incoming changesets
 via pretxnchangegroup and pretxncommit.
 
 The authorization is matched based on the local user name on the
 system where the hook runs, and not the committer of the original
 changeset (since the latter is merely informative).
 
 The acl hook is best used along with a restricted shell like hgsh,
 preventing authenticating users from doing anything other than pushing
 or pulling. The hook is not safe to use if users have interactive
 shell access, as they can then disable the hook. Nor is it safe if
 remote users share an account, because then there is no way to
 distinguish them.
 
 The order in which access checks are performed is:
 
 1) Deny  list for branches (section ``acl.deny.branches``)
 2) Allow list for branches (section ``acl.allow.branches``)
 3) Deny  list for paths    (section ``acl.deny``)
 4) Allow list for paths    (section ``acl.allow``)
 
 The allow and deny sections take key-value pairs.
 
 Branch-based Access Control
 ---------------------------
 
 Use the ``acl.deny.branches`` and ``acl.allow.branches`` sections to
 have branch-based access control. Keys in these sections can be
 either:
 
 - a branch name, or
 - an asterisk, to match any branch;
 
 The corresponding values can be either:
 
 - a comma-separated list containing users and groups, or
 - an asterisk, to match anyone;
 
 You can add the "!" prefix to a user or group name to invert the sense
 of the match.
 
 Path-based Access Control
 -------------------------
 
 Use the ``acl.deny`` and ``acl.allow`` sections to have path-based
 access control. Keys in these sections accept a subtree pattern (with
 a glob syntax by default). The corresponding values follow the same
 syntax as the other sections above.
 
 Groups
 ------
 
 Group names must be prefixed with an ``@`` symbol. Specifying a group
 name has the same effect as specifying all the users in that group.
 
 You can define group members in the ``acl.groups`` section.
 If a group name is not defined there, and Mercurial is running under
 a Unix-like system, the list of users will be taken from the OS.
 Otherwise, an exception will be raised.
 
 Example Configuration
 ---------------------
 
 ::
 
   [hooks]
 
   # Use this if you want to check access restrictions at commit time
   pretxncommit.acl = python:hgext.acl.hook
 
   # Use this if you want to check access restrictions for pull, push,
   # bundle and serve.
   pretxnchangegroup.acl = python:hgext.acl.hook
 
   [acl]
   # Allow or deny access for incoming changes only if their source is
   # listed here, let them pass otherwise. Source is "serve" for all
   # remote access (http or ssh), "push", "pull" or "bundle" when the
   # related commands are run locally.
   # Default: serve
   sources = serve
 
   [acl.deny.branches]
 
   # Everyone is denied to the frozen branch:
   frozen-branch = *
 
   # A bad user is denied on all branches:
   * = bad-user
 
   [acl.allow.branches]
 
   # A few users are allowed on branch-a:
   branch-a = user-1, user-2, user-3
 
   # Only one user is allowed on branch-b:
   branch-b = user-1
 
   # The super user is allowed on any branch:
   * = super-user
 
   # Everyone is allowed on branch-for-tests:
   branch-for-tests = *
 
   [acl.deny]
   # This list is checked first. If a match is found, acl.allow is not
   # checked. All users are granted access if acl.deny is not present.
   # Format for both lists: glob pattern = user, ..., @group, ...
 
   # To match everyone, use an asterisk for the user:
   # my/glob/pattern = *
 
   # user6 will not have write access to any file:
   ** = user6
 
   # Group "hg-denied" will not have write access to any file:
   ** = @hg-denied
 
   # Nobody will be able to change "DONT-TOUCH-THIS.txt", despite
   # everyone being able to change all other files. See below.
   src/main/resources/DONT-TOUCH-THIS.txt = *
 
   [acl.allow]
   # if acl.allow is not present, all users are allowed by default
   # empty acl.allow = no users allowed
 
   # User "doc_writer" has write access to any file under the "docs"
   # folder:
   docs/** = doc_writer
 
   # User "jack" and group "designers" have write access to any file
   # under the "images" folder:
   images/** = jack, @designers
 
   # Everyone (except for "user6" and "@hg-denied" - see acl.deny above)
   # will have write access to any file under the "resources" folder
   # (except for 1 file. See acl.deny):
   src/main/resources/** = *
 
   .hgtags = release_engineer
 
 Examples using the "!" prefix
 .............................
 
 Suppose there's a branch that only a given user (or group) should be able to
 push to, and you don't want to restrict access to any other branch that may
 be created.
 
 The "!" prefix allows you to prevent anyone except a given user or group to
 push changesets in a given branch or path.
 
 In the examples below, we will:
 1) Deny access to branch "ring" to anyone but user "gollum"
 2) Deny access to branch "lake" to anyone but members of the group "hobbit"
 3) Deny access to a file to anyone but user "gollum"
 
 ::
 
   [acl.allow.branches]
   # Empty
 
   [acl.deny.branches]
 
   # 1) only 'gollum' can commit to branch 'ring';
   # 'gollum' and anyone else can still commit to any other branch.
   ring = !gollum
 
   # 2) only members of the group 'hobbit' can commit to branch 'lake';
   # 'hobbit' members and anyone else can still commit to any other branch.
   lake = !@hobbit
 
   # You can also deny access based on file paths:
 
   [acl.allow]
   # Empty
 
   [acl.deny]
   # 3) only 'gollum' can change the file below;
   # 'gollum' and anyone else can still change any other file.
   /misty/mountains/cave/ring = !gollum
 
 '''
 
 from __future__ import absolute_import
 
 import getpass
 
 from mercurial.i18n import _
 from mercurial import (
     error,
+    extensions,
     match,
     registrar,
     util,
 )
 
 urlreq = util.urlreq
 
 # Note for extension authors: ONLY specify testedwith = 'ships-with-hg-core' for
 # extensions which SHIP WITH MERCURIAL. Non-mainline extensions should
 # be specifying the version(s) of Mercurial they are tested with, or
 # leave the attribute unspecified.
 testedwith = 'ships-with-hg-core'
 
 configtable = {}
 configitem = registrar.configitem(configtable)
 
 # deprecated config: acl.config
 configitem('acl', 'config',
     default=None,
 )
 configitem('acl.groups', '.*',
     default=None,
     generic=True,
 )
 configitem('acl.deny.branches', '.*',
     default=None,
     generic=True,
 )
 configitem('acl.allow.branches', '.*',
     default=None,
     generic=True,
 )
 configitem('acl.deny', '.*',
     default=None,
     generic=True,
 )
 configitem('acl.allow', '.*',
     default=None,
     generic=True,
 )
 configitem('acl', 'sources',
     default=lambda: ['serve'],
 )
 
 def _getusers(ui, group):
 
     # First, try to use group definition from section [acl.groups]
     hgrcusers = ui.configlist('acl.groups', group)
     if hgrcusers:
         return hgrcusers
 
     ui.debug('acl: "%s" not defined in [acl.groups]\n' % group)
     # If no users found in group definition, get users from OS-level group
     try:
         return util.groupmembers(group)
     except KeyError:
         raise error.Abort(_("group '%s' is undefined") % group)
 
 def _usermatch(ui, user, usersorgroups):
 
     if usersorgroups == '*':
         return True
 
     for ug in usersorgroups.replace(',', ' ').split():
 
         if ug.startswith('!'):
             # Test for excluded user or group. Format:
             # if ug is a user  name: !username
             # if ug is a group name: !@groupname
             ug = ug[1:]
             if not ug.startswith('@') and user != ug \
                 or ug.startswith('@') and user not in _getusers(ui, ug[1:]):
                 return True
 
         # Test for user or group. Format:
         # if ug is a user  name: username
         # if ug is a group name: @groupname
         elif user == ug \
              or ug.startswith('@') and user in _getusers(ui, ug[1:]):
             return True
 
     return False
 
 def buildmatch(ui, repo, user, key):
     '''return tuple of (match function, list enabled).'''
     if not ui.has_section(key):
         ui.debug('acl: %s not enabled\n' % key)
         return None
 
     pats = [pat for pat, users in ui.configitems(key)
             if _usermatch(ui, user, users)]
     ui.debug('acl: %s enabled, %d entries for user %s\n' %
              (key, len(pats), user))
 
     # Branch-based ACL
     if not repo:
         if pats:
             # If there's an asterisk (meaning "any branch"), always return True;
             # Otherwise, test if b is in pats
             if '*' in pats:
                 return util.always
             return lambda b: b in pats
         return util.never
 
     # Path-based ACL
     if pats:
         return match.match(repo.root, '', pats)
     return util.never
 
+def ensureenabled(ui):
+    """make sure the extension is enabled when used as hook
+
+    When acl is used through hooks, the extension is never formally loaded and
+    enabled. This has some side effect, for example the config declaration is
+    never loaded. This function ensure the extension is enabled when running
+    hooks.
+    """
+    if 'acl' in ui._knownconfig:
+        return
+    ui.setconfig('extensions', 'acl', '', source='internal')
+    extensions.loadall(ui, ['acl'])
+
 def hook(ui, repo, hooktype, node=None, source=None, **kwargs):
+
+    ensureenabled(ui)
+
     if hooktype not in ['pretxnchangegroup', 'pretxncommit']:
         raise error.Abort(_('config error - hook type "%s" cannot stop '
                            'incoming changesets nor commits') % hooktype)
     if (hooktype == 'pretxnchangegroup' and
         source not in ui.configlist('acl', 'sources')):
         ui.debug('acl: changes have source "%s" - skipping\n' % source)
         return
 
     user = None
     if source == 'serve' and 'url' in kwargs:
         url = kwargs['url'].split(':')
         if url[0] == 'remote' and url[1].startswith('http'):
             user = urlreq.unquote(url[3])
 
     if user is None:
         user = getpass.getuser()
 
     ui.debug('acl: checking access for user "%s"\n' % user)
 
     # deprecated config: acl.config
     cfg = ui.config('acl', 'config')
     if cfg:
         ui.readconfig(cfg, sections=['acl.groups', 'acl.allow.branches',
             'acl.deny.branches', 'acl.allow', 'acl.deny'])
 
     allowbranches = buildmatch(ui, None, user, 'acl.allow.branches')
     denybranches = buildmatch(ui, None, user, 'acl.deny.branches')
     allow = buildmatch(ui, repo, user, 'acl.allow')
     deny = buildmatch(ui, repo, user, 'acl.deny')
 
     for rev in xrange(repo[node], len(repo)):
         ctx = repo[rev]
         branch = ctx.branch()
         if denybranches and denybranches(branch):
             raise error.Abort(_('acl: user "%s" denied on branch "%s"'
                                ' (changeset "%s")')
                                % (user, branch, ctx))
         if allowbranches and not allowbranches(branch):
             raise error.Abort(_('acl: user "%s" not allowed on branch "%s"'
                                ' (changeset "%s")')
                                % (user, branch, ctx))
         ui.debug('acl: branch access granted: "%s" on branch "%s"\n'
         % (ctx, branch))
 
         for f in ctx.files():
             if deny and deny(f):
                 raise error.Abort(_('acl: user "%s" denied on "%s"'
                 ' (changeset "%s")') % (user, f, ctx))
             if allow and not allow(f):
                 raise error.Abort(_('acl: user "%s" not allowed on "%s"'
                 ' (changeset "%s")') % (user, f, ctx))
         ui.debug('acl: path access granted: "%s"\n' % ctx)