mercurial/dispatch.py

posix: use local reference to unlink

We have a local reference to os.unlink in module scope, but we still used
os.unlink inside functions. This changes util to use the local reference,
which will pave the way for combining duplicated code in future patches.

# dispatch.py - command dispatching for mercurial
#
# Copyright 2005-2007 Matt Mackall <[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.

from __future__ import absolute_import, print_function

import atexit
import difflib
import errno
import getopt
import os
import pdb
import re
import signal
import sys
import time
import traceback


from .i18n import _

from . import (
    cmdutil,
    color,
    commands,
    debugcommands,
    demandimport,
    encoding,
    error,
    extensions,
    fancyopts,
    fileset,
    help,
    hg,
    hook,
    profiling,
    pycompat,
    revset,
    scmutil,
    templatefilters,
    templatekw,
    templater,
    ui as uimod,
    util,
)

class request(object):
    def __init__(self, args, ui=None, repo=None, fin=None, fout=None,
                 ferr=None):
        self.args = args
        self.ui = ui
        self.repo = repo

        # input/output/error streams
        self.fin = fin
        self.fout = fout
        self.ferr = ferr

def run():
    "run the command in sys.argv"
    sys.exit((dispatch(request(pycompat.sysargv[1:])) or 0) & 255)

def _getsimilar(symbols, value):
    sim = lambda x: difflib.SequenceMatcher(None, value, x).ratio()
    # The cutoff for similarity here is pretty arbitrary. It should
    # probably be investigated and tweaked.
    return [s for s in symbols if sim(s) > 0.6]

def _reportsimilar(write, similar):
    if len(similar) == 1:
        write(_("(did you mean %s?)\n") % similar[0])
    elif similar:
        ss = ", ".join(sorted(similar))
        write(_("(did you mean one of %s?)\n") % ss)

def _formatparse(write, inst):
    similar = []
    if isinstance(inst, error.UnknownIdentifier):
        # make sure to check fileset first, as revset can invoke fileset
        similar = _getsimilar(inst.symbols, inst.function)
    if len(inst.args) > 1:
        write(_("hg: parse error at %s: %s\n") %
                         (inst.args[1], inst.args[0]))
        if (inst.args[0][0] == ' '):
            write(_("unexpected leading whitespace\n"))
    else:
        write(_("hg: parse error: %s\n") % inst.args[0])
        _reportsimilar(write, similar)
    if inst.hint:
        write(_("(%s)\n") % inst.hint)

def _formatargs(args):
    return ' '.join(util.shellquote(a) for a in args)

def dispatch(req):
    "run the command specified in req.args"
    if req.ferr:
        ferr = req.ferr
    elif req.ui:
        ferr = req.ui.ferr
    else:
        ferr = util.stderr

    try:
        if not req.ui:
            req.ui = uimod.ui.load()
        if '--traceback' in req.args:
            req.ui.setconfig('ui', 'traceback', 'on', '--traceback')

        # set ui streams from the request
        if req.fin:
            req.ui.fin = req.fin
        if req.fout:
            req.ui.fout = req.fout
        if req.ferr:
            req.ui.ferr = req.ferr
    except error.Abort as inst:
        ferr.write(_("abort: %s\n") % inst)
        if inst.hint:
            ferr.write(_("(%s)\n") % inst.hint)
        return -1
    except error.ParseError as inst:
        _formatparse(ferr.write, inst)
        return -1

    msg = _formatargs(req.args)
    starttime = util.timer()
    ret = None
    try:
        ret = _runcatch(req)
    except KeyboardInterrupt:
        try:
            req.ui.warn(_("interrupted!\n"))
        except IOError as inst:
            if inst.errno != errno.EPIPE:
                raise
        ret = -1
    finally:
        duration = util.timer() - starttime
        req.ui.flush()
        if req.ui.logblockedtimes:
            req.ui._blockedtimes['command_duration'] = duration * 1000
            req.ui.log('uiblocked', 'ui blocked ms', **req.ui._blockedtimes)
        req.ui.log("commandfinish", "%s exited %s after %0.2f seconds\n",
                   msg, ret or 0, duration)
    return ret

def _runcatch(req):
    def catchterm(*args):
        raise error.SignalInterrupt

    ui = req.ui
    try:
        for name in 'SIGBREAK', 'SIGHUP', 'SIGTERM':
            num = getattr(signal, name, None)
            if num:
                signal.signal(num, catchterm)
    except ValueError:
        pass # happens if called in a thread

    def _runcatchfunc():
        try:
            debugger = 'pdb'
            debugtrace = {
                'pdb' : pdb.set_trace
            }
            debugmortem = {
                'pdb' : pdb.post_mortem
            }

            # read --config before doing anything else
            # (e.g. to change trust settings for reading .hg/hgrc)
            cfgs = _parseconfig(req.ui, _earlygetopt(['--config'], req.args))

            if req.repo:
                # copy configs that were passed on the cmdline (--config) to
                # the repo ui
                for sec, name, val in cfgs:
                    req.repo.ui.setconfig(sec, name, val, source='--config')

            # developer config: ui.debugger
            debugger = ui.config("ui", "debugger")
            debugmod = pdb
            if not debugger or ui.plain():
                # if we are in HGPLAIN mode, then disable custom debugging
                debugger = 'pdb'
            elif '--debugger' in req.args:
                # This import can be slow for fancy debuggers, so only
                # do it when absolutely necessary, i.e. when actual
                # debugging has been requested
                with demandimport.deactivated():
                    try:
                        debugmod = __import__(debugger)
                    except ImportError:
                        pass # Leave debugmod = pdb

            debugtrace[debugger] = debugmod.set_trace
            debugmortem[debugger] = debugmod.post_mortem

            # enter the debugger before command execution
            if '--debugger' in req.args:
                ui.warn(_("entering debugger - "
                        "type c to continue starting hg or h for help\n"))

                if (debugger != 'pdb' and
                    debugtrace[debugger] == debugtrace['pdb']):
                    ui.warn(_("%s debugger specified "
                              "but its module was not found\n") % debugger)
                with demandimport.deactivated():
                    debugtrace[debugger]()
            try:
                return _dispatch(req)
            finally:
                ui.flush()
        except: # re-raises
            # enter the debugger when we hit an exception
            if '--debugger' in req.args:
                traceback.print_exc()
                debugmortem[debugger](sys.exc_info()[2])
            ui.traceback()
            raise

    return callcatch(ui, _runcatchfunc)

def callcatch(ui, func):
    """like scmutil.callcatch but handles more high-level exceptions about
    config parsing and commands. besides, use handlecommandexception to handle
    uncaught exceptions.
    """
    try:
        return scmutil.callcatch(ui, func)
    except error.AmbiguousCommand as inst:
        ui.warn(_("hg: command '%s' is ambiguous:\n    %s\n") %
                (inst.args[0], " ".join(inst.args[1])))
    except error.CommandError as inst:
        if inst.args[0]:
            ui.pager('help')
            ui.warn(_("hg %s: %s\n") % (inst.args[0], inst.args[1]))
            commands.help_(ui, inst.args[0], full=False, command=True)
        else:
            ui.pager('help')
            ui.warn(_("hg: %s\n") % inst.args[1])
            commands.help_(ui, 'shortlist')
    except error.ParseError as inst:
        _formatparse(ui.warn, inst)
        return -1
    except error.UnknownCommand as inst:
        nocmdmsg = _("hg: unknown command '%s'\n") % inst.args[0]
        try:
            # check if the command is in a disabled extension
            # (but don't check for extensions themselves)
            formatted = help.formattedhelp(ui, inst.args[0], unknowncmd=True)
            ui.warn(nocmdmsg)
            ui.write(formatted)
        except (error.UnknownCommand, error.Abort):
            suggested = False
            if len(inst.args) == 2:
                sim = _getsimilar(inst.args[1], inst.args[0])
                if sim:
                    ui.warn(nocmdmsg)
                    _reportsimilar(ui.warn, sim)
                    suggested = True
            if not suggested:
                ui.pager('help')
                ui.warn(nocmdmsg)
                commands.help_(ui, 'shortlist')
    except IOError:
        raise
    except KeyboardInterrupt:
        raise
    except:  # probably re-raises
        if not handlecommandexception(ui):
            raise

    return -1

def aliasargs(fn, givenargs):
    args = getattr(fn, 'args', [])
    if args:
        cmd = ' '.join(map(util.shellquote, args))

        nums = []
        def replacer(m):
            num = int(m.group(1)) - 1
            nums.append(num)
            if num < len(givenargs):
                return givenargs[num]
            raise error.Abort(_('too few arguments for command alias'))
        cmd = re.sub(br'\$(\d+|\$)', replacer, cmd)
        givenargs = [x for i, x in enumerate(givenargs)
                     if i not in nums]
        args = pycompat.shlexsplit(cmd)
    return args + givenargs

def aliasinterpolate(name, args, cmd):
    '''interpolate args into cmd for shell aliases

    This also handles $0, $@ and "$@".
    '''
    # util.interpolate can't deal with "$@" (with quotes) because it's only
    # built to match prefix + patterns.
    replacemap = dict(('$%d' % (i + 1), arg) for i, arg in enumerate(args))
    replacemap['$0'] = name
    replacemap['$$'] = '$'
    replacemap['$@'] = ' '.join(args)
    # Typical Unix shells interpolate "$@" (with quotes) as all the positional
    # parameters, separated out into words. Emulate the same behavior here by
    # quoting the arguments individually. POSIX shells will then typically
    # tokenize each argument into exactly one word.
    replacemap['"$@"'] = ' '.join(util.shellquote(arg) for arg in args)
    # escape '\$' for regex
    regex = '|'.join(replacemap.keys()).replace('$', r'\$')
    r = re.compile(regex)
    return r.sub(lambda x: replacemap[x.group()], cmd)

class cmdalias(object):
    def __init__(self, name, definition, cmdtable, source):
        self.name = self.cmd = name
        self.cmdname = ''
        self.definition = definition
        self.fn = None
        self.givenargs = []
        self.opts = []
        self.help = ''
        self.badalias = None
        self.unknowncmd = False
        self.source = source

        try:
            aliases, entry = cmdutil.findcmd(self.name, cmdtable)
            for alias, e in cmdtable.iteritems():
                if e is entry:
                    self.cmd = alias
                    break
            self.shadows = True
        except error.UnknownCommand:
            self.shadows = False

        if not self.definition:
            self.badalias = _("no definition for alias '%s'") % self.name
            return

        if self.definition.startswith('!'):
            self.shell = True
            def fn(ui, *args):
                env = {'HG_ARGS': ' '.join((self.name,) + args)}
                def _checkvar(m):
                    if m.groups()[0] == '$':
                        return m.group()
                    elif int(m.groups()[0]) <= len(args):
                        return m.group()
                    else:
                        ui.debug("No argument found for substitution "
                                 "of %i variable in alias '%s' definition."
                                 % (int(m.groups()[0]), self.name))
                        return ''
                cmd = re.sub(r'\$(\d+|\$)', _checkvar, self.definition[1:])
                cmd = aliasinterpolate(self.name, args, cmd)
                return ui.system(cmd, environ=env,
                                 blockedtag='alias_%s' % self.name)
            self.fn = fn
            return

        try:
            args = pycompat.shlexsplit(self.definition)
        except ValueError as inst:
            self.badalias = (_("error in definition for alias '%s': %s")
                             % (self.name, inst))
            return
        self.cmdname = cmd = args.pop(0)
        self.givenargs = args

        for invalidarg in ("--cwd", "-R", "--repository", "--repo", "--config"):
            if _earlygetopt([invalidarg], args):
                self.badalias = (_("error in definition for alias '%s': %s may "
                                   "only be given on the command line")
                                 % (self.name, invalidarg))
                return

        try:
            tableentry = cmdutil.findcmd(cmd, cmdtable, False)[1]
            if len(tableentry) > 2:
                self.fn, self.opts, self.help = tableentry
            else:
                self.fn, self.opts = tableentry

            if self.help.startswith("hg " + cmd):
                # drop prefix in old-style help lines so hg shows the alias
                self.help = self.help[4 + len(cmd):]
            self.__doc__ = self.fn.__doc__

        except error.UnknownCommand:
            self.badalias = (_("alias '%s' resolves to unknown command '%s'")
                             % (self.name, cmd))
            self.unknowncmd = True
        except error.AmbiguousCommand:
            self.badalias = (_("alias '%s' resolves to ambiguous command '%s'")
                             % (self.name, cmd))

    @property
    def args(self):
        args = map(util.expandpath, self.givenargs)
        return aliasargs(self.fn, args)

    def __getattr__(self, name):
        adefaults = {'norepo': True, 'optionalrepo': False, 'inferrepo': False}
        if name not in adefaults:
            raise AttributeError(name)
        if self.badalias or util.safehasattr(self, 'shell'):
            return adefaults[name]
        return getattr(self.fn, name)

    def __call__(self, ui, *args, **opts):
        if self.badalias:
            hint = None
            if self.unknowncmd:
                try:
                    # check if the command is in a disabled extension
                    cmd, ext = extensions.disabledcmd(ui, self.cmdname)[:2]
                    hint = _("'%s' is provided by '%s' extension") % (cmd, ext)
                except error.UnknownCommand:
                    pass
            raise error.Abort(self.badalias, hint=hint)
        if self.shadows:
            ui.debug("alias '%s' shadows command '%s'\n" %
                     (self.name, self.cmdname))

        ui.log('commandalias', "alias '%s' expands to '%s'\n",
               self.name, self.definition)
        if util.safehasattr(self, 'shell'):
            return self.fn(ui, *args, **opts)
        else:
            try:
                return util.checksignature(self.fn)(ui, *args, **opts)
            except error.SignatureError:
                args = ' '.join([self.cmdname] + self.args)
                ui.debug("alias '%s' expands to '%s'\n" % (self.name, args))
                raise

def addaliases(ui, cmdtable):
    # aliases are processed after extensions have been loaded, so they
    # may use extension commands. Aliases can also use other alias definitions,
    # but only if they have been defined prior to the current definition.
    for alias, definition in ui.configitems('alias'):
        source = ui.configsource('alias', alias)
        aliasdef = cmdalias(alias, definition, cmdtable, source)

        try:
            olddef = cmdtable[aliasdef.cmd][0]
            if olddef.definition == aliasdef.definition:
                continue
        except (KeyError, AttributeError):
            # definition might not exist or it might not be a cmdalias
            pass

        cmdtable[aliasdef.name] = (aliasdef, aliasdef.opts, aliasdef.help)

def _parse(ui, args):
    options = {}
    cmdoptions = {}

    try:
        args = fancyopts.fancyopts(args, commands.globalopts, options)
    except getopt.GetoptError as inst:
        raise error.CommandError(None, inst)

    if args:
        cmd, args = args[0], args[1:]
        aliases, entry = cmdutil.findcmd(cmd, commands.table,
                                         ui.configbool("ui", "strict"))
        cmd = aliases[0]
        args = aliasargs(entry[0], args)
        defaults = ui.config("defaults", cmd)
        if defaults:
            args = pycompat.maplist(
                util.expandpath, pycompat.shlexsplit(defaults)) + args
        c = list(entry[1])
    else:
        cmd = None
        c = []

    # combine global options into local
    for o in commands.globalopts:
        c.append((o[0], o[1], options[o[1]], o[3]))

    try:
        args = fancyopts.fancyopts(args, c, cmdoptions, gnu=True)
    except getopt.GetoptError as inst:
        raise error.CommandError(cmd, inst)

    # separate global options back out
    for o in commands.globalopts:
        n = o[1]
        options[n] = cmdoptions[n]
        del cmdoptions[n]

    return (cmd, cmd and entry[0] or None, args, options, cmdoptions)

def _parseconfig(ui, config):
    """parse the --config options from the command line"""
    configs = []

    for cfg in config:
        try:
            name, value = [cfgelem.strip()
                           for cfgelem in cfg.split('=', 1)]
            section, name = name.split('.', 1)
            if not section or not name:
                raise IndexError
            ui.setconfig(section, name, value, '--config')
            configs.append((section, name, value))
        except (IndexError, ValueError):
            raise error.Abort(_('malformed --config option: %r '
                               '(use --config section.name=value)') % cfg)

    return configs

def _earlygetopt(aliases, args):
    """Return list of values for an option (or aliases).

    The values are listed in the order they appear in args.
    The options and values are removed from args.

    >>> args = ['x', '--cwd', 'foo', 'y']
    >>> _earlygetopt(['--cwd'], args), args
    (['foo'], ['x', 'y'])

    >>> args = ['x', '--cwd=bar', 'y']
    >>> _earlygetopt(['--cwd'], args), args
    (['bar'], ['x', 'y'])

    >>> args = ['x', '-R', 'foo', 'y']
    >>> _earlygetopt(['-R'], args), args
    (['foo'], ['x', 'y'])

    >>> args = ['x', '-Rbar', 'y']
    >>> _earlygetopt(['-R'], args), args
    (['bar'], ['x', 'y'])
    """
    try:
        argcount = args.index("--")
    except ValueError:
        argcount = len(args)
    shortopts = [opt for opt in aliases if len(opt) == 2]
    values = []
    pos = 0
    while pos < argcount:
        fullarg = arg = args[pos]
        equals = arg.find('=')
        if equals > -1:
            arg = arg[:equals]
        if arg in aliases:
            del args[pos]
            if equals > -1:
                values.append(fullarg[equals + 1:])
                argcount -= 1
            else:
                if pos + 1 >= argcount:
                    # ignore and let getopt report an error if there is no value
                    break
                values.append(args.pop(pos))
                argcount -= 2
        elif arg[:2] in shortopts:
            # short option can have no following space, e.g. hg log -Rfoo
            values.append(args.pop(pos)[2:])
            argcount -= 1
        else:
            pos += 1
    return values

def runcommand(lui, repo, cmd, fullargs, ui, options, d, cmdpats, cmdoptions):
    # run pre-hook, and abort if it fails
    hook.hook(lui, repo, "pre-%s" % cmd, True, args=" ".join(fullargs),
              pats=cmdpats, opts=cmdoptions)
    try:
        ret = _runcommand(ui, options, cmd, d)
        # run post-hook, passing command result
        hook.hook(lui, repo, "post-%s" % cmd, False, args=" ".join(fullargs),
                  result=ret, pats=cmdpats, opts=cmdoptions)
    except Exception:
        # run failure hook and re-raise
        hook.hook(lui, repo, "fail-%s" % cmd, False, args=" ".join(fullargs),
                  pats=cmdpats, opts=cmdoptions)
        raise
    return ret

def _getlocal(ui, rpath, wd=None):
    """Return (path, local ui object) for the given target path.

    Takes paths in [cwd]/.hg/hgrc into account."
    """
    if wd is None:
        try:
            wd = pycompat.getcwd()
        except OSError as e:
            raise error.Abort(_("error getting current working directory: %s") %
                              e.strerror)
    path = cmdutil.findrepo(wd) or ""
    if not path:
        lui = ui
    else:
        lui = ui.copy()
        lui.readconfig(os.path.join(path, ".hg", "hgrc"), path)

    if rpath and rpath[-1]:
        path = lui.expandpath(rpath[-1])
        lui = ui.copy()
        lui.readconfig(os.path.join(path, ".hg", "hgrc"), path)

    return path, lui

def _checkshellalias(lui, ui, args):
    """Return the function to run the shell alias, if it is required"""
    options = {}

    try:
        args = fancyopts.fancyopts(args, commands.globalopts, options)
    except getopt.GetoptError:
        return

    if not args:
        return

    cmdtable = commands.table

    cmd = args[0]
    try:
        strict = ui.configbool("ui", "strict")
        aliases, entry = cmdutil.findcmd(cmd, cmdtable, strict)
    except (error.AmbiguousCommand, error.UnknownCommand):
        return

    cmd = aliases[0]
    fn = entry[0]

    if cmd and util.safehasattr(fn, 'shell'):
        d = lambda: fn(ui, *args[1:])
        return lambda: runcommand(lui, None, cmd, args[:1], ui, options, d,
                                  [], {})

_loaded = set()

# list of (objname, loadermod, loadername) tuple:
# - objname is the name of an object in extension module, from which
#   extra information is loaded
# - loadermod is the module where loader is placed
# - loadername is the name of the function, which takes (ui, extensionname,
#   extraobj) arguments
extraloaders = [
    ('cmdtable', commands, 'loadcmdtable'),
    ('colortable', color, 'loadcolortable'),
    ('filesetpredicate', fileset, 'loadpredicate'),
    ('revsetpredicate', revset, 'loadpredicate'),
    ('templatefilter', templatefilters, 'loadfilter'),
    ('templatefunc', templater, 'loadfunction'),
    ('templatekeyword', templatekw, 'loadkeyword'),
]

def _dispatch(req):
    args = req.args
    ui = req.ui

    # check for cwd
    cwd = _earlygetopt(['--cwd'], args)
    if cwd:
        os.chdir(cwd[-1])

    rpath = _earlygetopt(["-R", "--repository", "--repo"], args)
    path, lui = _getlocal(ui, rpath)

    # Side-effect of accessing is debugcommands module is guaranteed to be
    # imported and commands.table is populated.
    debugcommands.command

    uis = set([ui, lui])

    if req.repo:
        uis.add(req.repo.ui)

    if '--profile' in args:
        for ui_ in uis:
            ui_.setconfig('profiling', 'enabled', 'true', '--profile')

    with profiling.maybeprofile(lui):
        # Configure extensions in phases: uisetup, extsetup, cmdtable, and
        # reposetup. Programs like TortoiseHg will call _dispatch several
        # times so we keep track of configured extensions in _loaded.
        extensions.loadall(lui)
        exts = [ext for ext in extensions.extensions() if ext[0] not in _loaded]
        # Propagate any changes to lui.__class__ by extensions
        ui.__class__ = lui.__class__

        # (uisetup and extsetup are handled in extensions.loadall)

        for name, module in exts:
            for objname, loadermod, loadername in extraloaders:
                extraobj = getattr(module, objname, None)
                if extraobj is not None:
                    getattr(loadermod, loadername)(ui, name, extraobj)
            _loaded.add(name)

        # (reposetup is handled in hg.repository)

        addaliases(lui, commands.table)

        # All aliases and commands are completely defined, now.
        # Check abbreviation/ambiguity of shell alias.
        shellaliasfn = _checkshellalias(lui, ui, args)
        if shellaliasfn:
            return shellaliasfn()

        # check for fallback encoding
        fallback = lui.config('ui', 'fallbackencoding')
        if fallback:
            encoding.fallbackencoding = fallback

        fullargs = args
        cmd, func, args, options, cmdoptions = _parse(lui, args)

        if options["config"]:
            raise error.Abort(_("option --config may not be abbreviated!"))
        if options["cwd"]:
            raise error.Abort(_("option --cwd may not be abbreviated!"))
        if options["repository"]:
            raise error.Abort(_(
                "option -R has to be separated from other options (e.g. not "
                "-qR) and --repository may only be abbreviated as --repo!"))

        if options["encoding"]:
            encoding.encoding = options["encoding"]
        if options["encodingmode"]:
            encoding.encodingmode = options["encodingmode"]
        if options["time"]:
            def get_times():
                t = os.times()
                if t[4] == 0.0:
                    # Windows leaves this as zero, so use time.clock()
                    t = (t[0], t[1], t[2], t[3], time.clock())
                return t
            s = get_times()
            def print_time():
                t = get_times()
                ui.warn(
                    _("time: real %.3f secs (user %.3f+%.3f sys %.3f+%.3f)\n") %
                    (t[4]-s[4], t[0]-s[0], t[2]-s[2], t[1]-s[1], t[3]-s[3]))
            atexit.register(print_time)

        if options['verbose'] or options['debug'] or options['quiet']:
            for opt in ('verbose', 'debug', 'quiet'):
                val = str(bool(options[opt]))
                if pycompat.ispy3:
                    val = val.encode('ascii')
                for ui_ in uis:
                    ui_.setconfig('ui', opt, val, '--' + opt)

        if options['traceback']:
            for ui_ in uis:
                ui_.setconfig('ui', 'traceback', 'on', '--traceback')

        if options['noninteractive']:
            for ui_ in uis:
                ui_.setconfig('ui', 'interactive', 'off', '-y')

        if util.parsebool(options['pager']):
            ui.pager('internal-always-' + cmd)
        elif options['pager'] != 'auto':
            ui.disablepager()

        if cmdoptions.get('insecure', False):
            for ui_ in uis:
                ui_.insecureconnections = True

        # setup color handling
        coloropt = options['color']
        for ui_ in uis:
            if coloropt:
                ui_.setconfig('ui', 'color', coloropt, '--color')
            color.setup(ui_)

        if options['version']:
            return commands.version_(ui)
        if options['help']:
            return commands.help_(ui, cmd, command=cmd is not None)
        elif not cmd:
            return commands.help_(ui, 'shortlist')

        repo = None
        cmdpats = args[:]
        if not func.norepo:
            # use the repo from the request only if we don't have -R
            if not rpath and not cwd:
                repo = req.repo

            if repo:
                # set the descriptors of the repo ui to those of ui
                repo.ui.fin = ui.fin
                repo.ui.fout = ui.fout
                repo.ui.ferr = ui.ferr
            else:
                try:
                    repo = hg.repository(ui, path=path)
                    if not repo.local():
                        raise error.Abort(_("repository '%s' is not local")
                                          % path)
                    repo.ui.setconfig("bundle", "mainreporoot", repo.root,
                                      'repo')
                except error.RequirementError:
                    raise
                except error.RepoError:
                    if rpath and rpath[-1]: # invalid -R path
                        raise
                    if not func.optionalrepo:
                        if func.inferrepo and args and not path:
                            # try to infer -R from command args
                            repos = map(cmdutil.findrepo, args)
                            guess = repos[0]
                            if guess and repos.count(guess) == len(repos):
                                req.args = ['--repository', guess] + fullargs
                                return _dispatch(req)
                        if not path:
                            raise error.RepoError(_("no repository found in"
                                                    " '%s' (.hg not found)")
                                                  % pycompat.getcwd())
                        raise
            if repo:
                ui = repo.ui
                if options['hidden']:
                    repo = repo.unfiltered()
            args.insert(0, repo)
        elif rpath:
            ui.warn(_("warning: --repository ignored\n"))

        msg = _formatargs(fullargs)
        ui.log("command", '%s\n', msg)
        strcmdopt = pycompat.strkwargs(cmdoptions)
        d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
        try:
            return runcommand(lui, repo, cmd, fullargs, ui, options, d,
                              cmdpats, cmdoptions)
        finally:
            if repo and repo != req.repo:
                repo.close()

def _runcommand(ui, options, cmd, cmdfunc):
    """Run a command function, possibly with profiling enabled."""
    try:
        return cmdfunc()
    except error.SignatureError:
        raise error.CommandError(cmd, _('invalid arguments'))

def _exceptionwarning(ui):
    """Produce a warning message for the current active exception"""

    # For compatibility checking, we discard the portion of the hg
    # version after the + on the assumption that if a "normal
    # user" is running a build with a + in it the packager
    # probably built from fairly close to a tag and anyone with a
    # 'make local' copy of hg (where the version number can be out
    # of date) will be clueful enough to notice the implausible
    # version number and try updating.
    ct = util.versiontuple(n=2)
    worst = None, ct, ''
    if ui.config('ui', 'supportcontact', None) is None:
        for name, mod in extensions.extensions():
            testedwith = getattr(mod, 'testedwith', '')
            if pycompat.ispy3 and isinstance(testedwith, str):
                testedwith = testedwith.encode(u'utf-8')
            report = getattr(mod, 'buglink', _('the extension author.'))
            if not testedwith.strip():
                # We found an untested extension. It's likely the culprit.
                worst = name, 'unknown', report
                break

            # Never blame on extensions bundled with Mercurial.
            if extensions.ismoduleinternal(mod):
                continue

            tested = [util.versiontuple(t, 2) for t in testedwith.split()]
            if ct in tested:
                continue

            lower = [t for t in tested if t < ct]
            nearest = max(lower or tested)
            if worst[0] is None or nearest < worst[1]:
                worst = name, nearest, report
    if worst[0] is not None:
        name, testedwith, report = worst
        if not isinstance(testedwith, (bytes, str)):
            testedwith = '.'.join([str(c) for c in testedwith])
        warning = (_('** Unknown exception encountered with '
                     'possibly-broken third-party extension %s\n'
                     '** which supports versions %s of Mercurial.\n'
                     '** Please disable %s and try your action again.\n'
                     '** If that fixes the bug please report it to %s\n')
                   % (name, testedwith, name, report))
    else:
        bugtracker = ui.config('ui', 'supportcontact', None)
        if bugtracker is None:
            bugtracker = _("https://mercurial-scm.org/wiki/BugTracker")
        warning = (_("** unknown exception encountered, "
                     "please report by visiting\n** ") + bugtracker + '\n')
    if pycompat.ispy3:
        sysversion = sys.version.encode(u'utf-8')
    else:
        sysversion = sys.version
    sysversion = sysversion.replace('\n', '')
    warning += ((_("** Python %s\n") % sysversion) +
                (_("** Mercurial Distributed SCM (version %s)\n") %
                 util.version()) +
                (_("** Extensions loaded: %s\n") %
                 ", ".join([x[0] for x in extensions.extensions()])))
    return warning

def handlecommandexception(ui):
    """Produce a warning message for broken commands

    Called when handling an exception; the exception is reraised if
    this function returns False, ignored otherwise.
    """
    warning = _exceptionwarning(ui)
    ui.log("commandexception", "%s\n%s\n", warning, traceback.format_exc())
    ui.warn(warning)
    return False  # re-raise the exception