dispatch: always load extensions before running shell aliases (issue5230)

Before this patch, we may or may not load extensions for shell aliases
depending on whether the command is abbreviated or not.

Loading extensions may have useful side effects to shell aliases. For example,
the pager extension does not work for shell aliases.

This patch removes the code checking shell aliases before loading extensions
to give the user a more consistent experience. It may hurt performance for
shell aliases a bit without chg but the correctness seems worth it. It will
also make the behavior consistent with chg since chg will always load all
extensions before running commands.

mercurial/dispatch.py

@@ -1,1094 +1,1077 b''
 # 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 os
 import pdb
 import re
 import shlex
 import signal
 import socket
 import sys
 import time
 import traceback
 
 
 from .i18n import _
 
 from . import (
     cmdutil,
     commands,
     demandimport,
     encoding,
     error,
     extensions,
     fancyopts,
     fileset,
     hg,
     hook,
     revset,
     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(sys.argv[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 dispatch(req):
     "run the command specified in req.args"
     if req.ferr:
         ferr = req.ferr
     elif req.ui:
         ferr = req.ui.ferr
     else:
         ferr = sys.stderr
 
     try:
         if not req.ui:
             req.ui = uimod.ui()
         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 = ' '.join(' ' in a and repr(a) or a for a in req.args)
     starttime = time.time()
     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 = time.time() - starttime
         req.ui.flush()
         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
 
     try:
         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
 
     # Global exception handling, alphabetically
     # Mercurial-specific first, followed by built-in and library exceptions
     except error.AmbiguousCommand as inst:
         ui.warn(_("hg: command '%s' is ambiguous:\n    %s\n") %
                 (inst.args[0], " ".join(inst.args[1])))
     except error.ParseError as inst:
         _formatparse(ui.warn, inst)
         return -1
     except error.LockHeld as inst:
         if inst.errno == errno.ETIMEDOUT:
             reason = _('timed out waiting for lock held by %s') % inst.locker
         else:
             reason = _('lock held by %s') % inst.locker
         ui.warn(_("abort: %s: %s\n") % (inst.desc or inst.filename, reason))
     except error.LockUnavailable as inst:
         ui.warn(_("abort: could not lock %s: %s\n") %
                (inst.desc or inst.filename, inst.strerror))
     except error.CommandError as inst:
         if inst.args[0]:
             ui.warn(_("hg %s: %s\n") % (inst.args[0], inst.args[1]))
             commands.help_(ui, inst.args[0], full=False, command=True)
         else:
             ui.warn(_("hg: %s\n") % inst.args[1])
             commands.help_(ui, 'shortlist')
     except error.OutOfBandError as inst:
         if inst.args:
             msg = _("abort: remote error:\n")
         else:
             msg = _("abort: remote error\n")
         ui.warn(msg)
         if inst.args:
             ui.warn(''.join(inst.args))
         if inst.hint:
             ui.warn('(%s)\n' % inst.hint)
     except error.RepoError as inst:
         ui.warn(_("abort: %s!\n") % inst)
         if inst.hint:
             ui.warn(_("(%s)\n") % inst.hint)
     except error.ResponseError as inst:
         ui.warn(_("abort: %s") % inst.args[0])
         if not isinstance(inst.args[1], basestring):
             ui.warn(" %r\n" % (inst.args[1],))
         elif not inst.args[1]:
             ui.warn(_(" empty string\n"))
         else:
             ui.warn("\n%r\n" % util.ellipsis(inst.args[1]))
     except error.CensoredNodeError as inst:
         ui.warn(_("abort: file censored %s!\n") % inst)
     except error.RevlogError as inst:
         ui.warn(_("abort: %s!\n") % inst)
     except error.SignalInterrupt:
         ui.warn(_("killed!\n"))
     except error.UnknownCommand as inst:
         ui.warn(_("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)
             commands.help_(ui, inst.args[0], unknowncmd=True)
         except (error.UnknownCommand, error.Abort):
             suggested = False
             if len(inst.args) == 2:
                 sim = _getsimilar(inst.args[1], inst.args[0])
                 if sim:
                     _reportsimilar(ui.warn, sim)
                     suggested = True
             if not suggested:
                 commands.help_(ui, 'shortlist')
     except error.InterventionRequired as inst:
         ui.warn("%s\n" % inst)
         if inst.hint:
             ui.warn(_("(%s)\n") % inst.hint)
         return 1
     except error.Abort as inst:
         ui.warn(_("abort: %s\n") % inst)
         if inst.hint:
             ui.warn(_("(%s)\n") % inst.hint)
     except ImportError as inst:
         ui.warn(_("abort: %s!\n") % inst)
         m = str(inst).split()[-1]
         if m in "mpatch bdiff".split():
             ui.warn(_("(did you forget to compile extensions?)\n"))
         elif m in "zlib".split():
             ui.warn(_("(is your Python install correct?)\n"))
     except IOError as inst:
         if util.safehasattr(inst, "code"):
             ui.warn(_("abort: %s\n") % inst)
         elif util.safehasattr(inst, "reason"):
             try: # usually it is in the form (errno, strerror)
                 reason = inst.reason.args[1]
             except (AttributeError, IndexError):
                 # it might be anything, for example a string
                 reason = inst.reason
             if isinstance(reason, unicode):
                 # SSLError of Python 2.7.9 contains a unicode
                 reason = reason.encode(encoding.encoding, 'replace')
             ui.warn(_("abort: error: %s\n") % reason)
         elif (util.safehasattr(inst, "args")
               and inst.args and inst.args[0] == errno.EPIPE):
             pass
         elif getattr(inst, "strerror", None):
             if getattr(inst, "filename", None):
                 ui.warn(_("abort: %s: %s\n") % (inst.strerror, inst.filename))
             else:
                 ui.warn(_("abort: %s\n") % inst.strerror)
         else:
             raise
     except OSError as inst:
         if getattr(inst, "filename", None) is not None:
             ui.warn(_("abort: %s: '%s'\n") % (inst.strerror, inst.filename))
         else:
             ui.warn(_("abort: %s\n") % inst.strerror)
     except KeyboardInterrupt:
         raise
     except MemoryError:
         ui.warn(_("abort: out of memory\n"))
     except SystemExit as inst:
         # Commands shouldn't sys.exit directly, but give a return code.
         # Just in case catch this and and pass exit code to caller.
         return inst.code
     except socket.error as inst:
         ui.warn(_("abort: %s\n") % inst.args[-1])
     except:  # perhaps 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(r'\$(\d+|\$)', replacer, cmd)
         givenargs = [x for i, x in enumerate(givenargs)
                      if i not in nums]
         args = shlex.split(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)
             self.fn = fn
             return
 
         try:
             args = shlex.split(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))
 
         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 fancyopts.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 = map(util.expandpath, shlex.split(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, True)
     except fancyopts.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 = os.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, precheck=True):
-    """Return the function to run the shell alias, if it is required
-
-    'precheck' is whether this function is invoked before adding
-    aliases or not.
-    """
+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 fancyopts.getopt.GetoptError:
         return
 
     if not args:
         return
 
-    if precheck:
-        strict = True
-        cmdtable = commands.table.copy()
-        addaliases(lui, cmdtable)
-    else:
-        strict = False
-        cmdtable = commands.table
+    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,
                                   [], {})
 
 def _cmdattr(ui, cmd, func, attr):
     try:
         return getattr(func, attr)
     except AttributeError:
         ui.deprecwarn("missing attribute '%s', use @command decorator "
                       "to register '%s'" % (attr, cmd), '3.8')
         return False
 
 _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'),
     ('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)
 
-    # Now that we're operating in the right directory/repository with
-    # the right config settings, check for shell aliases
-    shellaliasfn = _checkshellalias(lui, ui, args)
-    if shellaliasfn:
-        return shellaliasfn()
-
     # 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)
 
-    if not lui.configbool("ui", "strict"):
-        # All aliases and commands are completely defined, now.
-        # Check abbreviation/ambiguity of shell alias again, because shell
-        # alias may cause failure of "_parse" (see issue4355)
-        shellaliasfn = _checkshellalias(lui, ui, args, precheck=False)
-        if shellaliasfn:
-            return shellaliasfn()
+    # 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)
 
     uis = set([ui, lui])
 
     if req.repo:
         uis.add(req.repo.ui)
 
     if options['verbose'] or options['debug'] or options['quiet']:
         for opt in ('verbose', 'debug', 'quiet'):
             val = str(bool(options[opt]))
             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 cmdoptions.get('insecure', False):
         for ui_ in uis:
             ui_.insecureconnections = True
 
     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 _cmdattr(ui, cmd, 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 _cmdattr(ui, cmd, func, 'optionalrepo'):
                     if (_cmdattr(ui, cmd, 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)")
                                               % os.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 = ' '.join(' ' in a and repr(a) or a for a in fullargs)
     ui.log("command", '%s\n', msg)
     d = lambda: util.checksignature(func)(ui, *args, **cmdoptions)
     try:
         return runcommand(lui, repo, cmd, fullargs, ui, options, d,
                           cmdpats, cmdoptions)
     finally:
         if repo and repo != req.repo:
             repo.close()
 
 def lsprofile(ui, func, fp):
     format = ui.config('profiling', 'format', default='text')
     field = ui.config('profiling', 'sort', default='inlinetime')
     limit = ui.configint('profiling', 'limit', default=30)
     climit = ui.configint('profiling', 'nested', default=0)
 
     if format not in ['text', 'kcachegrind']:
         ui.warn(_("unrecognized profiling format '%s'"
                     " - Ignored\n") % format)
         format = 'text'
 
     try:
         from . import lsprof
     except ImportError:
         raise error.Abort(_(
             'lsprof not available - install from '
             'http://codespeak.net/svn/user/arigo/hack/misc/lsprof/'))
     p = lsprof.Profiler()
     p.enable(subcalls=True)
     try:
         return func()
     finally:
         p.disable()
 
         if format == 'kcachegrind':
             from . import lsprofcalltree
             calltree = lsprofcalltree.KCacheGrind(p)
             calltree.output(fp)
         else:
             # format == 'text'
             stats = lsprof.Stats(p.getstats())
             stats.sort(field)
             stats.pprint(limit=limit, file=fp, climit=climit)
 
 def flameprofile(ui, func, fp):
     try:
         from flamegraph import flamegraph
     except ImportError:
         raise error.Abort(_(
             'flamegraph not available - install from '
             'https://github.com/evanhempel/python-flamegraph'))
     # developer config: profiling.freq
     freq = ui.configint('profiling', 'freq', default=1000)
     filter_ = None
     collapse_recursion = True
     thread = flamegraph.ProfileThread(fp, 1.0 / freq,
                                       filter_, collapse_recursion)
     start_time = time.clock()
     try:
         thread.start()
         func()
     finally:
         thread.stop()
         thread.join()
         print('Collected %d stack frames (%d unique) in %2.2f seconds.' % (
             time.clock() - start_time, thread.num_frames(),
             thread.num_frames(unique=True)))
 
 
 def statprofile(ui, func, fp):
     try:
         import statprof
     except ImportError:
         raise error.Abort(_(
             'statprof not available - install using "easy_install statprof"'))
 
     freq = ui.configint('profiling', 'freq', default=1000)
     if freq > 0:
         statprof.reset(freq)
     else:
         ui.warn(_("invalid sampling frequency '%s' - ignoring\n") % freq)
 
     statprof.start()
     try:
         return func()
     finally:
         statprof.stop()
         statprof.display(fp)
 
 def _runcommand(ui, options, cmd, cmdfunc):
     """Enables the profiler if applicable.
 
     ``profiling.enabled`` - boolean config that enables or disables profiling
     """
     def checkargs():
         try:
             return cmdfunc()
         except error.SignatureError:
             raise error.CommandError(cmd, _("invalid arguments"))
 
     if options['profile'] or ui.configbool('profiling', 'enabled'):
         profiler = os.getenv('HGPROF')
         if profiler is None:
             profiler = ui.config('profiling', 'type', default='ls')
         if profiler not in ('ls', 'stat', 'flame'):
             ui.warn(_("unrecognized profiler '%s' - ignored\n") % profiler)
             profiler = 'ls'
 
         output = ui.config('profiling', 'output')
 
         if output == 'blackbox':
             fp = util.stringio()
         elif output:
             path = ui.expandpath(output)
             fp = open(path, 'wb')
         else:
             fp = sys.stderr
 
         try:
             if profiler == 'ls':
                 return lsprofile(ui, checkargs, fp)
             elif profiler == 'flame':
                 return flameprofile(ui, checkargs, fp)
             else:
                 return statprofile(ui, checkargs, fp)
         finally:
             if output:
                 if output == 'blackbox':
                     val = "Profile:\n%s" % fp.getvalue()
                     # ui.log treats the input as a format string,
                     # so we need to escape any % signs.
                     val = val.replace('%', '%%')
                     ui.log('profile', val)
                 fp.close()
     else:
         return checkargs()
 
 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', '')
             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 testedwith == 'internal':
                 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, 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')
     warning += ((_("** Python %s\n") % sys.version.replace('\n', '')) +
                 (_("** 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

tests/test-pager.t

@@ -1,179 +1,191 b''
   $ cat >> fakepager.py <<EOF
   > import sys
   > for line in sys.stdin:
   >     sys.stdout.write('paged! %r\n' % line)
   > EOF
 
 Enable ui.formatted because pager won't fire without it, and set up
 pager and tell it to use our fake pager that lets us see when the
 pager was running.
   $ cat >> $HGRCPATH <<EOF
   > [ui]
   > formatted = yes
   > [extensions]
   > pager=
   > [pager]
   > pager = python $TESTTMP/fakepager.py
   > EOF
 
   $ hg init repo
   $ cd repo
   $ echo a >> a
   $ hg add a
   $ hg ci -m 'add a'
   $ for x in `python $TESTDIR/seq.py 1 10`; do
   >   echo a $x >> a
   >   hg ci -m "modify a $x"
   > done
 
 By default diff and log are paged, but summary is not:
 
   $ hg diff -c 2 --pager=yes
   paged! 'diff -r f4be7687d414 -r bce265549556 a\n'
   paged! '--- a/a\tThu Jan 01 00:00:00 1970 +0000\n'
   paged! '+++ b/a\tThu Jan 01 00:00:00 1970 +0000\n'
   paged! '@@ -1,2 +1,3 @@\n'
   paged! ' a\n'
   paged! ' a 1\n'
   paged! '+a 2\n'
 
   $ hg log --limit 2
   paged! 'changeset:   10:46106edeeb38\n'
   paged! 'tag:         tip\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 10\n'
   paged! '\n'
   paged! 'changeset:   9:6dd8ea7dd621\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 9\n'
   paged! '\n'
 
   $ hg summary
   parent: 10:46106edeeb38 tip
    modify a 10
   branch: default
   commit: (clean)
   update: (current)
   phases: 11 draft
 
 We can enable the pager on summary:
 
   $ hg --config pager.attend-summary=yes summary
   paged! 'parent: 10:46106edeeb38 tip\n'
   paged! ' modify a 10\n'
   paged! 'branch: default\n'
   paged! 'commit: (clean)\n'
   paged! 'update: (current)\n'
   paged! 'phases: 11 draft\n'
 
 If we completely change the attend list that's respected:
 
   $ hg --config pager.attend-diff=no diff -c 2
   diff -r f4be7687d414 -r bce265549556 a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,2 +1,3 @@
    a
    a 1
   +a 2
 
   $ hg --config pager.attend=summary diff -c 2
   diff -r f4be7687d414 -r bce265549556 a
   --- a/a	Thu Jan 01 00:00:00 1970 +0000
   +++ b/a	Thu Jan 01 00:00:00 1970 +0000
   @@ -1,2 +1,3 @@
    a
    a 1
   +a 2
 
 If 'log' is in attend, then 'history' should also be paged:
   $ hg history --limit 2 --config pager.attend=log
   paged! 'changeset:   10:46106edeeb38\n'
   paged! 'tag:         tip\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 10\n'
   paged! '\n'
   paged! 'changeset:   9:6dd8ea7dd621\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 9\n'
   paged! '\n'
 
 Possible bug: history is explicitly ignored in pager config, but
 because log is in the attend list it still gets pager treatment.
 
   $ hg history --limit 2 --config pager.attend=log \
   >   --config pager.ignore=history
   paged! 'changeset:   10:46106edeeb38\n'
   paged! 'tag:         tip\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 10\n'
   paged! '\n'
   paged! 'changeset:   9:6dd8ea7dd621\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 9\n'
   paged! '\n'
 
 Possible bug: history is explicitly marked as attend-history=no, but
 it doesn't fail to get paged because log is still in the attend list.
 
   $ hg history --limit 2 --config pager.attend-history=no
   paged! 'changeset:   10:46106edeeb38\n'
   paged! 'tag:         tip\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 10\n'
   paged! '\n'
   paged! 'changeset:   9:6dd8ea7dd621\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 9\n'
   paged! '\n'
 
 Possible bug: disabling pager for log but enabling it for history
 doesn't result in history being paged.
 
   $ hg history --limit 2 --config pager.attend-log=no \
   > --config pager.attend-history=yes
   changeset:   10:46106edeeb38
   tag:         tip
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     modify a 10
   
   changeset:   9:6dd8ea7dd621
   user:        test
   date:        Thu Jan 01 00:00:00 1970 +0000
   summary:     modify a 9
   
 
 Pager with color enabled allows colors to come through by default,
 even though stdout is no longer a tty.
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > color=
   > [color]
   > mode = ansi
   > EOF
   $ hg log --limit 3
   paged! '\x1b[0;33mchangeset:   10:46106edeeb38\x1b[0m\n'
   paged! 'tag:         tip\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 10\n'
   paged! '\n'
   paged! '\x1b[0;33mchangeset:   9:6dd8ea7dd621\x1b[0m\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 9\n'
   paged! '\n'
   paged! '\x1b[0;33mchangeset:   8:cff05a6312fe\x1b[0m\n'
   paged! 'user:        test\n'
   paged! 'date:        Thu Jan 01 00:00:00 1970 +0000\n'
   paged! 'summary:     modify a 8\n'
   paged! '\n'
+
+Pager works with shell aliases.
+
+  $ cat >> $HGRCPATH <<EOF
+  > [alias]
+  > echoa = !echo a
+  > EOF
+
+  $ hg echoa
+  a
+  $ hg --config pager.attend-echoa=yes echoa
+  paged! 'a\n'