githelp: fail gracefully in a couple cases where arguments are missing

I didn't bother adding tests because the other commands that already handled
missing arguments don't test these edge cases.  I didn't read over all of the
code, rather I scanned for `args` not being checked before indexing.

hgext/githelp.py

@@ -1,1079 +1,1090
 # githelp.py - Try to map Git commands to Mercurial equivalents.
 #
 # Copyright 2013 Facebook, Inc.
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 """try mapping git commands to Mercurial commands
 
 Tries to map a given git command to a Mercurial command:
 
   $ hg githelp -- git checkout master
   hg update master
 
 If an unknown command or parameter combination is detected, an error is
 produced.
 """
 
 from __future__ import absolute_import
 
 import getopt
 import re
 
 from mercurial.i18n import _
 from mercurial import (
     encoding,
     error,
     fancyopts,
     registrar,
     scmutil,
 )
 from mercurial.utils import (
     procutil,
 )
 
 # 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'
 
 cmdtable = {}
 command = registrar.command(cmdtable)
 
 def convert(s):
     if s.startswith("origin/"):
         return s[7:]
     if 'HEAD' in s:
         s = s.replace('HEAD', '.')
     # HEAD~ in git is .~1 in mercurial
     s = re.sub('~$', '~1', s)
     return s
 
 @command('^githelp|git', [
     ], _('hg githelp'))
 def githelp(ui, repo, *args, **kwargs):
     '''suggests the Mercurial equivalent of the given git command
 
     Usage: hg githelp -- <git command>
     '''
 
     if len(args) == 0 or (len(args) == 1 and args[0] =='git'):
         raise error.Abort(_('missing git command - '
                             'usage: hg githelp -- <git command>'))
 
     if args[0] == 'git':
         args = args[1:]
 
     cmd = args[0]
     if not cmd in gitcommands:
         raise error.Abort("error: unknown git command %s" % (cmd))
 
     ui.pager('githelp')
     args = args[1:]
     return gitcommands[cmd](ui, repo, *args, **kwargs)
 
 def parseoptions(ui, cmdoptions, args):
     cmdoptions = list(cmdoptions)
     opts = {}
     args = list(args)
     while True:
         try:
             args = fancyopts.fancyopts(list(args), cmdoptions, opts, True)
             break
         except getopt.GetoptError as ex:
             flag = None
             if "requires argument" in ex.msg:
                 raise
             if ('--' + ex.opt) in ex.msg:
                 flag = '--' + ex.opt
             elif ('-' + ex.opt) in ex.msg:
                 flag = '-' + ex.opt
             else:
                 raise error.Abort("unknown option %s" % ex.opt)
             try:
                 args.remove(flag)
             except Exception:
                 raise error.Abort(
                     "unknown option {0} packed with other options\n"
                     "Please try passing the option as it's own flag: -{0}" \
                     .format(ex.opt))
 
             ui.warn(_("ignoring unknown option %s\n") % flag)
 
     args = list([convert(x) for x in args])
     opts = dict([(k, convert(v)) if isinstance(v, str) else (k, v)
                                  for k, v in opts.iteritems()])
 
     return args, opts
 
 class Command(object):
     def __init__(self, name):
         self.name = name
         self.args = []
         self.opts = {}
 
     def __bytes__(self):
         cmd = "hg " + self.name
         if self.opts:
             for k, values in sorted(self.opts.iteritems()):
                 for v in values:
                     if v:
                         cmd += " %s %s" % (k, v)
                     else:
                         cmd += " %s" % (k,)
         if self.args:
             cmd += " "
             cmd += " ".join(self.args)
         return cmd
 
     __str__ = encoding.strmethod(__bytes__)
 
     def append(self, value):
         self.args.append(value)
 
     def extend(self, values):
         self.args.extend(values)
 
     def __setitem__(self, key, value):
         values = self.opts.setdefault(key, [])
         values.append(value)
 
     def __and__(self, other):
         return AndCommand(self, other)
 
 class AndCommand(object):
     def __init__(self, left, right):
         self.left = left
         self.right = right
 
     def __str__(self):
         return "%s && %s" % (self.left, self.right)
 
     def __and__(self, other):
         return AndCommand(self, other)
 
 def add(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('A', 'all', None, ''),
         ('p', 'patch', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if (opts.get('patch')):
         ui.status(_("note: Mercurial will commit when complete, "
                     "as there is no staging area in Mercurial\n\n"))
         cmd = Command('commit --interactive')
     else:
         cmd = Command("add")
 
         if not opts.get('all'):
             cmd.extend(args)
         else:
             ui.status(_("note: use hg addremove to remove files that have "
                         "been deleted.\n\n"))
 
     ui.status((bytes(cmd)), "\n")
 
 def am(ui, repo, *args, **kwargs):
     cmdoptions=[
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
     cmd = Command('import')
     ui.status(bytes(cmd), "\n")
 
 def apply(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('p', 'p', int, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('import --no-commit')
     if (opts.get('p')):
         cmd['-p'] = opts.get('p')
     cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def bisect(ui, repo, *args, **kwargs):
     ui.status(_("See 'hg help bisect' for how to use bisect.\n\n"))
 
 def blame(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
     cmd = Command('annotate -udl')
     cmd.extend([convert(v) for v in args])
     ui.status((bytes(cmd)), "\n")
 
 def branch(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'set-upstream', None, ''),
         ('', 'set-upstream-to', '', ''),
         ('d', 'delete', None, ''),
         ('D', 'delete', None, ''),
         ('m', 'move', None, ''),
         ('M', 'move', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command("bookmark")
 
     if opts.get('set_upstream') or opts.get('set_upstream_to'):
         ui.status(_("Mercurial has no concept of upstream branches\n"))
         return
     elif opts.get('delete'):
         cmd = Command("strip")
         for branch in args:
             cmd['-B'] = branch
         else:
             cmd['-B'] = None
     elif opts.get('move'):
         if len(args) > 0:
             if len(args) > 1:
                 old = args.pop(0)
             else:
                 # shell command to output the active bookmark for the active
                 # revision
                 old = '`hg log -T"{activebookmark}" -r .`'
+        else:
+            raise error.Abort(_('missing newbranch argument'))
         new = args[0]
         cmd['-m'] = old
         cmd.append(new)
     else:
         if len(args) > 1:
             cmd['-r'] = args[1]
             cmd.append(args[0])
         elif len(args) == 1:
             cmd.append(args[0])
     ui.status((bytes(cmd)), "\n")
 
 def ispath(repo, string):
     """
     The first argument to git checkout can either be a revision or a path. Let's
     generally assume it's a revision, unless it's obviously a path. There are
     too many ways to spell revisions in git for us to reasonably catch all of
     them, so let's be conservative.
     """
     if scmutil.isrevsymbol(repo, string):
         # if it's definitely a revision let's not even check if a file of the
         # same name exists.
         return False
 
     cwd = repo.getcwd()
     if cwd == '':
         repopath = string
     else:
         repopath = cwd + '/' + string
 
     exists = repo.wvfs.exists(repopath)
     if exists:
         return True
 
     manifest = repo['.'].manifest()
 
     didexist = (repopath in manifest) or manifest.hasdir(repopath)
 
     return didexist
 
 def checkout(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('b', 'branch', '', ''),
         ('B', 'branch', '', ''),
         ('f', 'force', None, ''),
         ('p', 'patch', None, ''),
     ]
     paths = []
     if '--' in args:
         sepindex = args.index('--')
         paths.extend(args[sepindex + 1:])
         args = args[:sepindex]
 
     args, opts = parseoptions(ui, cmdoptions, args)
 
     rev = None
     if args and ispath(repo, args[0]):
         paths = args + paths
     elif args:
         rev = args[0]
         paths = args[1:] + paths
 
     cmd = Command('update')
 
     if opts.get('force'):
         if paths or rev:
             cmd['-C'] = None
 
     if opts.get('patch'):
         cmd = Command('revert')
         cmd['-i'] = None
 
     if opts.get('branch'):
         if len(args) == 0:
             cmd = Command('bookmark')
             cmd.append(opts.get('branch'))
         else:
             cmd.append(args[0])
             bookcmd = Command('bookmark')
             bookcmd.append(opts.get('branch'))
             cmd = cmd & bookcmd
     # if there is any path argument supplied, use revert instead of update
     elif len(paths) > 0:
         ui.status(_("note: use --no-backup to avoid creating .orig files\n\n"))
         cmd = Command('revert')
         if opts.get('patch'):
             cmd['-i'] = None
         if rev:
             cmd['-r'] = rev
         cmd.extend(paths)
     elif rev:
         if opts.get('patch'):
             cmd['-r'] = rev
         else:
             cmd.append(rev)
     elif opts.get('force'):
         cmd = Command('revert')
         cmd['--all'] = None
     else:
         raise error.Abort("a commit must be specified")
 
     ui.status((bytes(cmd)), "\n")
 
 def cherrypick(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'continue', None, ''),
         ('', 'abort', None, ''),
         ('e', 'edit', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('graft')
 
     if opts.get('edit'):
         cmd['--edit'] = None
     if opts.get('continue'):
         cmd['--continue'] = None
     elif opts.get('abort'):
         ui.status(_("note: hg graft does not have --abort.\n\n"))
         return
     else:
         cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def clean(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('d', 'd', None, ''),
         ('f', 'force', None, ''),
         ('x', 'x', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('purge')
     if opts.get('x'):
         cmd['--all'] = None
     cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def clone(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'bare', None, ''),
         ('n', 'no-checkout', None, ''),
         ('b', 'branch', '', ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if len(args) == 0:
         raise error.Abort("a repository to clone must be specified")
 
     cmd = Command('clone')
     cmd.append(args[0])
     if len(args) > 1:
         cmd.append(args[1])
 
     if opts.get('bare'):
         cmd['-U'] = None
         ui.status(_("note: Mercurial does not have bare clones. " +
             "-U will clone the repo without checking out a commit\n\n"))
     elif opts.get('no_checkout'):
         cmd['-U'] = None
 
     if opts.get('branch'):
         cocmd = Command("update")
         cocmd.append(opts.get('branch'))
         cmd = cmd & cocmd
 
     ui.status((bytes(cmd)), "\n")
 
 def commit(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('a', 'all', None, ''),
         ('m', 'message', '', ''),
         ('p', 'patch', None, ''),
         ('C', 'reuse-message', '', ''),
         ('F', 'file', '', ''),
         ('', 'author', '', ''),
         ('', 'date', '', ''),
         ('', 'amend', None, ''),
         ('', 'no-edit', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('commit')
     if opts.get('patch'):
         cmd = Command('commit --interactive')
 
     if opts.get('amend'):
         if opts.get('no_edit'):
             cmd = Command('amend')
         else:
             cmd['--amend'] = None
 
     if opts.get('reuse_message'):
         cmd['-M'] = opts.get('reuse_message')
 
     if opts.get('message'):
         cmd['-m'] = "'%s'" % (opts.get('message'),)
 
     if opts.get('all'):
         ui.status(_("note: Mercurial doesn't have a staging area, " +
             "so there is no --all. -A will add and remove files " +
             "for you though.\n\n"))
 
     if opts.get('file'):
         cmd['-l'] = opts.get('file')
 
     if opts.get('author'):
         cmd['-u'] = opts.get('author')
 
     if opts.get('date'):
         cmd['-d'] = opts.get('date')
 
     cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def deprecated(ui, repo, *args, **kwargs):
     ui.warn(_('This command has been deprecated in the git project, ' +
         'thus isn\'t supported by this tool.\n\n'))
 
 def diff(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('a', 'all', None, ''),
         ('', 'cached', None, ''),
         ('R', 'reverse', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('diff')
 
     if opts.get('cached'):
         ui.status(_('note: Mercurial has no concept of a staging area, ' +
             'so --cached does nothing.\n\n'))
 
     if opts.get('reverse'):
         cmd['--reverse'] = None
 
     for a in list(args):
         args.remove(a)
         try:
             repo.revs(a)
             cmd['-r'] = a
         except Exception:
             cmd.append(a)
 
     ui.status((bytes(cmd)), "\n")
 
 def difftool(ui, repo, *args, **kwargs):
     ui.status(_('Mercurial does not enable external difftool by default. You '
         'need to enable the extdiff extension in your .hgrc file by adding\n'
         'extdiff =\n'
         'to the [extensions] section and then running\n\n'
         'hg extdiff -p <program>\n\n'
         'See \'hg help extdiff\' and \'hg help -e extdiff\' for more '
         'information.\n'))
 
 def fetch(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'all', None, ''),
         ('f', 'force', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('pull')
 
     if len(args) > 0:
         cmd.append(args[0])
         if len(args) > 1:
             ui.status(_("note: Mercurial doesn't have refspecs. " +
                 "-r can be used to specify which commits you want to pull. " +
                 "-B can be used to specify which bookmark you want to pull." +
                 "\n\n"))
             for v in args[1:]:
                 if v in repo._bookmarks:
                     cmd['-B'] = v
                 else:
                     cmd['-r'] = v
 
     ui.status((bytes(cmd)), "\n")
 
 def grep(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('grep')
 
     # For basic usage, git grep and hg grep are the same. They both have the
     # pattern first, followed by paths.
     cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def init(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('init')
 
     if len(args) > 0:
         cmd.append(args[0])
 
     ui.status((bytes(cmd)), "\n")
 
 def log(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'follow', None, ''),
         ('', 'decorate', None, ''),
         ('n', 'number', '', ''),
         ('1', '1', None, ''),
         ('', 'pretty', '', ''),
         ('', 'format', '', ''),
         ('', 'oneline', None, ''),
         ('', 'stat', None, ''),
         ('', 'graph', None, ''),
         ('p', 'patch', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
     ui.status(_('note: -v prints the entire commit message like Git does. To ' +
               'print just the first line, drop the -v.\n\n'))
     ui.status(_("note: see hg help revset for information on how to filter " +
         "log output.\n\n"))
 
     cmd = Command('log')
     cmd['-v'] = None
 
     if opts.get('number'):
         cmd['-l'] = opts.get('number')
     if opts.get('1'):
         cmd['-l'] = '1'
     if opts.get('stat'):
         cmd['--stat'] = None
     if opts.get('graph'):
         cmd['-G'] = None
     if opts.get('patch'):
         cmd['-p'] = None
 
     if opts.get('pretty') or opts.get('format') or opts.get('oneline'):
         format = opts.get('format', '')
         if 'format:' in format:
             ui.status(_("note: --format format:??? equates to Mercurial's " +
                 "--template. See hg help templates for more info.\n\n"))
             cmd['--template'] = '???'
         else:
             ui.status(_("note: --pretty/format/oneline equate to Mercurial's " +
                 "--style or --template. See hg help templates for more info." +
                 "\n\n"))
             cmd['--style'] = '???'
 
     if len(args) > 0:
         if '..' in args[0]:
             since, until = args[0].split('..')
             cmd['-r'] = "'%s::%s'" % (since, until)
             del args[0]
         cmd.extend(args)
 
     ui.status((bytes(cmd)), "\n")
 
 def lsfiles(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('c', 'cached', None, ''),
         ('d', 'deleted', None, ''),
         ('m', 'modified', None, ''),
         ('o', 'others', None, ''),
         ('i', 'ignored', None, ''),
         ('s', 'stage', None, ''),
         ('z', '_zero', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if (opts.get('modified') or opts.get('deleted')
         or opts.get('others') or opts.get('ignored')):
         cmd = Command('status')
         if opts.get('deleted'):
             cmd['-d'] = None
         if opts.get('modified'):
             cmd['-m'] = None
         if opts.get('others'):
             cmd['-o'] = None
         if opts.get('ignored'):
             cmd['-i'] = None
     else:
         cmd = Command('files')
     if opts.get('stage'):
         ui.status(_("note: Mercurial doesn't have a staging area, ignoring "
                   "--stage\n"))
     if opts.get('_zero'):
         cmd['-0'] = None
     cmd.append('.')
     for include in args:
         cmd['-I'] = procutil.shellquote(include)
 
     ui.status((bytes(cmd)), "\n")
 
 def merge(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('merge')
 
     if len(args) > 0:
         cmd.append(args[len(args) - 1])
 
     ui.status((bytes(cmd)), "\n")
 
 def mergebase(ui, repo, *args, **kwargs):
     cmdoptions = []
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if len(args) != 2:
         args = ['A', 'B']
 
     cmd = Command("log -T '{node}\\n' -r 'ancestor(%s,%s)'"
                   % (args[0], args[1]))
 
     ui.status(_('NOTE: ancestors() is part of the revset language.\n'),
               _("Learn more about revsets with 'hg help revsets'\n\n"))
     ui.status((bytes(cmd)), "\n")
 
 def mergetool(ui, repo, *args, **kwargs):
     cmdoptions = []
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command("resolve")
 
     if len(args) == 0:
         cmd['--all'] = None
     cmd.extend(args)
     ui.status((bytes(cmd)), "\n")
 
 def mv(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('f', 'force', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('mv')
     cmd.extend(args)
 
     if opts.get('force'):
         cmd['-f'] = None
 
     ui.status((bytes(cmd)), "\n")
 
 def pull(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'all', None, ''),
         ('f', 'force', None, ''),
         ('r', 'rebase', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('pull')
     cmd['--rebase'] = None
 
     if len(args) > 0:
         cmd.append(args[0])
         if len(args) > 1:
             ui.status(_("note: Mercurial doesn't have refspecs. " +
                 "-r can be used to specify which commits you want to pull. " +
                 "-B can be used to specify which bookmark you want to pull." +
                 "\n\n"))
             for v in args[1:]:
                 if v in repo._bookmarks:
                     cmd['-B'] = v
                 else:
                     cmd['-r'] = v
 
     ui.status((bytes(cmd)), "\n")
 
 def push(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'all', None, ''),
         ('f', 'force', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('push')
 
     if len(args) > 0:
         cmd.append(args[0])
         if len(args) > 1:
             ui.status(_("note: Mercurial doesn't have refspecs. " +
                 "-r can be used to specify which commits you want to push. " +
                 "-B can be used to specify which bookmark you want to push." +
                 "\n\n"))
             for v in args[1:]:
                 if v in repo._bookmarks:
                     cmd['-B'] = v
                 else:
                     cmd['-r'] = v
 
     if opts.get('force'):
         cmd['-f'] = None
 
     ui.status((bytes(cmd)), "\n")
 
 def rebase(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'all', None, ''),
         ('i', 'interactive', None, ''),
         ('', 'onto', '', ''),
         ('', 'abort', None, ''),
         ('', 'continue', None, ''),
         ('', 'skip', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if opts.get('interactive'):
         ui.status(_("note: hg histedit does not perform a rebase. " +
             "It just edits history.\n\n"))
         cmd = Command('histedit')
         if len(args) > 0:
             ui.status(_("also note: 'hg histedit' will automatically detect"
                       " your stack, so no second argument is necessary.\n\n"))
         ui.status((bytes(cmd)), "\n")
         return
 
     if opts.get('skip'):
         cmd = Command('revert --all -r .')
         ui.status((bytes(cmd)), "\n")
 
     cmd = Command('rebase')
 
     if opts.get('continue') or opts.get('skip'):
         cmd['--continue'] = None
     if opts.get('abort'):
         cmd['--abort'] = None
 
     if opts.get('onto'):
         ui.status(_("note: if you're trying to lift a commit off one branch, " +
             "try hg rebase -d <destination commit> -s <commit to be lifted>" +
             "\n\n"))
         cmd['-d'] = convert(opts.get('onto'))
         if len(args) < 2:
             raise error.Abort("Expected format: git rebase --onto X Y Z")
         cmd['-s'] = "'::%s - ::%s'" % (convert(args[1]), convert(args[0]))
     else:
         if len(args) == 1:
             cmd['-d'] = convert(args[0])
         elif len(args) == 2:
             cmd['-d'] = convert(args[0])
             cmd['-b'] = convert(args[1])
 
     ui.status((bytes(cmd)), "\n")
 
 def reflog(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'all', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('journal')
     if opts.get('all'):
         cmd['--all'] = None
     if len(args) > 0:
         cmd.append(args[0])
 
     ui.status(bytes(cmd), "\n\n")
     ui.status(_("note: in hg commits can be deleted from repo but we always"
               " have backups.\n"))
 
 def reset(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'soft', None, ''),
         ('', 'hard', None, ''),
         ('', 'mixed', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     commit = convert(args[0] if len(args) > 0 else '.')
     hard = opts.get('hard')
 
     if opts.get('mixed'):
         ui.status(_('NOTE: --mixed has no meaning since Mercurial has no '
                     'staging area\n\n'))
     if opts.get('soft'):
         ui.status(_('NOTE: --soft has no meaning since Mercurial has no '
                     'staging area\n\n'))
 
     cmd = Command('update')
     if hard:
         cmd.append('--clean')
 
     cmd.append(commit)
 
     ui.status((bytes(cmd)), "\n")
 
 def revert(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if len(args) > 1:
         ui.status(_("note: hg backout doesn't support multiple commits at " +
                     "once\n\n"))
 
     cmd = Command('backout')
     if args:
         cmd.append(args[0])
 
     ui.status((bytes(cmd)), "\n")
 
 def revparse(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'show-cdup', None, ''),
         ('', 'show-toplevel', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if opts.get('show_cdup') or opts.get('show_toplevel'):
         cmd = Command('root')
         if opts.get('show_cdup'):
             ui.status(_("note: hg root prints the root of the repository\n\n"))
         ui.status((bytes(cmd)), "\n")
     else:
         ui.status(_("note: see hg help revset for how to refer to commits\n"))
 
 def rm(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('f', 'force', None, ''),
         ('n', 'dry-run', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('rm')
     cmd.extend(args)
 
     if opts.get('force'):
         cmd['-f'] = None
     if opts.get('dry_run'):
         cmd['-n'] = None
 
     ui.status((bytes(cmd)), "\n")
 
 def show(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'name-status', None, ''),
         ('', 'pretty', '', ''),
         ('U', 'unified', int, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if opts.get('name_status'):
         if opts.get('pretty') == 'format:':
             cmd = Command('status')
             cmd['--change'] = '.'
         else:
             cmd = Command('log')
             cmd.append('--style status')
             cmd.append('-r .')
     elif len(args) > 0:
         if ispath(repo, args[0]):
             cmd = Command('cat')
         else:
             cmd = Command('export')
         cmd.extend(args)
         if opts.get('unified'):
             cmd.append('--config diff.unified=%d' % (opts['unified'],))
     elif opts.get('unified'):
         cmd = Command('export')
         cmd.append('--config diff.unified=%d' % (opts['unified'],))
     else:
         cmd = Command('export')
 
     ui.status((bytes(cmd)), "\n")
 
 def stash(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('shelve')
     action = args[0] if len(args) > 0 else None
 
     if action == 'list':
         cmd['-l'] = None
     elif action == 'drop':
         cmd['-d'] = None
         if len(args) > 1:
             cmd.append(args[1])
         else:
             cmd.append('<shelve name>')
     elif action == 'pop' or action == 'apply':
         cmd = Command('unshelve')
         if len(args) > 1:
             cmd.append(args[1])
         if action == 'apply':
             cmd['--keep'] = None
     elif (action == 'branch' or action == 'show' or action == 'clear'
         or action == 'create'):
         ui.status(_("note: Mercurial doesn't have equivalents to the " +
             "git stash branch, show, clear, or create actions.\n\n"))
         return
     else:
         if len(args) > 0:
             if args[0] != 'save':
                 cmd['--name'] = args[0]
             elif len(args) > 1:
                 cmd['--name'] = args[1]
 
     ui.status((bytes(cmd)), "\n")
 
 def status(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('', 'ignored', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('status')
     cmd.extend(args)
 
     if opts.get('ignored'):
         cmd['-i'] = None
 
     ui.status((bytes(cmd)), "\n")
 
 def svn(ui, repo, *args, **kwargs):
+    if not args:
+        raise error.Abort(_('missing svn command'))
     svncmd = args[0]
     if not svncmd in gitsvncommands:
         ui.warn(_("error: unknown git svn command %s\n") % (svncmd))
 
     args = args[1:]
     return gitsvncommands[svncmd](ui, repo, *args, **kwargs)
 
 def svndcommit(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('push')
 
     ui.status((bytes(cmd)), "\n")
 
 def svnfetch(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     cmd = Command('pull')
     cmd.append('default-push')
 
     ui.status((bytes(cmd)), "\n")
 
 def svnfindrev(ui, repo, *args, **kwargs):
     cmdoptions = [
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
+    if not args:
+        raise error.Abort(_('missing find-rev argument'))
+
     cmd = Command('log')
     cmd['-r'] = args[0]
 
     ui.status((bytes(cmd)), "\n")
 
 def svnrebase(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('l', 'local', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     pullcmd = Command('pull')
     pullcmd.append('default-push')
     rebasecmd = Command('rebase')
     rebasecmd.append('tip')
 
     cmd = pullcmd & rebasecmd
 
     ui.status((bytes(cmd)), "\n")
 
 def tag(ui, repo, *args, **kwargs):
     cmdoptions = [
         ('f', 'force', None, ''),
         ('l', 'list', None, ''),
         ('d', 'delete', None, ''),
     ]
     args, opts = parseoptions(ui, cmdoptions, args)
 
     if opts.get('list'):
         cmd = Command('tags')
     else:
         cmd = Command('tag')
+
+        if not args:
+            raise error.Abort(_('missing tag argument'))
+
         cmd.append(args[0])
         if len(args) > 1:
             cmd['-r'] = args[1]
 
         if opts.get('delete'):
             cmd['--remove'] = None
 
         if opts.get('force'):
             cmd['-f'] = None
 
     ui.status((bytes(cmd)), "\n")
 
 gitcommands = {
     'add': add,
     'am': am,
     'apply': apply,
     'bisect': bisect,
     'blame': blame,
     'branch': branch,
     'checkout': checkout,
     'cherry-pick': cherrypick,
     'clean': clean,
     'clone': clone,
     'commit': commit,
     'diff': diff,
     'difftool': difftool,
     'fetch': fetch,
     'grep': grep,
     'init': init,
     'log': log,
     'ls-files': lsfiles,
     'merge': merge,
     'merge-base': mergebase,
     'mergetool': mergetool,
     'mv': mv,
     'pull': pull,
     'push': push,
     'rebase': rebase,
     'reflog': reflog,
     'reset': reset,
     'revert': revert,
     'rev-parse': revparse,
     'rm': rm,
     'show': show,
     'stash': stash,
     'status': status,
     'svn': svn,
     'tag': tag,
     'whatchanged': deprecated,
 }
 
 gitsvncommands = {
     'dcommit': svndcommit,
     'fetch': svnfetch,
     'find-rev': svnfindrev,
     'rebase': svnrebase,
 }