hgext/alias.py

fix pull racing with push/commit (issue1320)

changegroup() has a problem when nodes which does not descend from a node
in <bases> are added to remote after the discovery phase.
If that happens, changegroup() won't send the correct set of nodes, ie.
some nodes will be missing.
To correct it we have to find the set of nodes that both remote and self
have (called <common>), and send all the nodes not in <common>.

This fix has some overhead, in the worst case it will re-send a whole branch.

A proper fix to avoid this overhead might be to change the protocol so that
the <common> nodes are sent (instead of the <bases> of the missing nodes).

# Copyright (C) 2007 Brendan Cully <[e-mail]>
# This file is published under the GNU GPL.

'''allow user-defined command aliases

To use, create entries in your hgrc of the form

[alias]
mycmd = cmd --args
'''

from mercurial.cmdutil import findcmd, UnknownCommand, AmbiguousCommand
from mercurial import commands
from mercurial.i18n import _

cmdtable = {}

class RecursiveCommand(Exception): pass

class lazycommand(object):
    '''defer command lookup until needed, so that extensions loaded
    after alias can be aliased'''
    def __init__(self, ui, name, target):
        self._ui = ui
        self._name = name
        self._target = target
        self._cmd = None

    def __len__(self):
        self._resolve()
        return len(self._cmd)

    def __getitem__(self, key):
        self._resolve()
        return self._cmd[key]

    def __iter__(self):
        self._resolve()
        return self._cmd.__iter__()

    def _resolve(self):
        if self._cmd is not None:
            return

        try:
            self._cmd = findcmd(self._target, commands.table, False)[1]
            if self._cmd == self:
                raise RecursiveCommand()
            if self._target in commands.norepo.split(' '):
                commands.norepo += ' %s' % self._name
            return
        except UnknownCommand:
            msg = _('*** [alias] %s: command %s is unknown') % \
                  (self._name, self._target)
        except AmbiguousCommand:
            msg = _('*** [alias] %s: command %s is ambiguous') % \
                  (self._name, self._target)
        except RecursiveCommand:
            msg = _('*** [alias] %s: circular dependency on %s') % \
                  (self._name, self._target)
        def nocmd(*args, **opts):
            self._ui.warn(msg + '\n')
            return 1
        nocmd.__doc__ = msg
        self._cmd = (nocmd, [], '')
        commands.norepo += ' %s' % self._name

def uisetup(ui):
    for cmd, target in ui.configitems('alias'):
        if not target:
            ui.warn(_('*** [alias] %s: no definition\n') % cmd)
            continue
        args = target.split(' ')
        tcmd = args.pop(0)
        if args:
            ui.setconfig('defaults', cmd, ' '.join(args))
        cmdtable[cmd] = lazycommand(ui, cmd, tcmd)