help: check if a subtopic exists and raise an error if it doesn't (issue6145)

Differential Revision: https://phab.mercurial-scm.org/D6441

mercurial/help.py

@@ -1,869 +1,871
 # help.py - help data for mercurial
 #
 # Copyright 2006 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
 
 import itertools
 import os
 import re
 import textwrap
 
 from .i18n import (
     _,
     gettext,
 )
 from . import (
     cmdutil,
     encoding,
     error,
     extensions,
     fancyopts,
     filemerge,
     fileset,
     minirst,
     pycompat,
     registrar,
     revset,
     templatefilters,
     templatefuncs,
     templatekw,
     ui as uimod,
     util,
 )
 from .hgweb import (
     webcommands,
 )
 from .utils import (
     compression,
 )
 
 _exclkeywords = {
     "(ADVANCED)",
     "(DEPRECATED)",
     "(EXPERIMENTAL)",
     # i18n: "(ADVANCED)" is a keyword, must be translated consistently
     _("(ADVANCED)"),
     # i18n: "(DEPRECATED)" is a keyword, must be translated consistently
     _("(DEPRECATED)"),
     # i18n: "(EXPERIMENTAL)" is a keyword, must be translated consistently
     _("(EXPERIMENTAL)"),
 }
 
 # The order in which command categories will be displayed.
 # Extensions with custom categories should insert them into this list
 # after/before the appropriate item, rather than replacing the list or
 # assuming absolute positions.
 CATEGORY_ORDER = [
     registrar.command.CATEGORY_REPO_CREATION,
     registrar.command.CATEGORY_REMOTE_REPO_MANAGEMENT,
     registrar.command.CATEGORY_COMMITTING,
     registrar.command.CATEGORY_CHANGE_MANAGEMENT,
     registrar.command.CATEGORY_CHANGE_ORGANIZATION,
     registrar.command.CATEGORY_FILE_CONTENTS,
     registrar.command.CATEGORY_CHANGE_NAVIGATION ,
     registrar.command.CATEGORY_WORKING_DIRECTORY,
     registrar.command.CATEGORY_IMPORT_EXPORT,
     registrar.command.CATEGORY_MAINTENANCE,
     registrar.command.CATEGORY_HELP,
     registrar.command.CATEGORY_MISC,
     registrar.command.CATEGORY_NONE,
 ]
 
 # Human-readable category names. These are translated.
 # Extensions with custom categories should add their names here.
 CATEGORY_NAMES = {
     registrar.command.CATEGORY_REPO_CREATION: 'Repository creation',
     registrar.command.CATEGORY_REMOTE_REPO_MANAGEMENT:
         'Remote repository management',
     registrar.command.CATEGORY_COMMITTING: 'Change creation',
     registrar.command.CATEGORY_CHANGE_NAVIGATION: 'Change navigation',
     registrar.command.CATEGORY_CHANGE_MANAGEMENT: 'Change manipulation',
     registrar.command.CATEGORY_CHANGE_ORGANIZATION: 'Change organization',
     registrar.command.CATEGORY_WORKING_DIRECTORY:
         'Working directory management',
     registrar.command.CATEGORY_FILE_CONTENTS: 'File content management',
     registrar.command.CATEGORY_IMPORT_EXPORT: 'Change import/export',
     registrar.command.CATEGORY_MAINTENANCE: 'Repository maintenance',
     registrar.command.CATEGORY_HELP: 'Help',
     registrar.command.CATEGORY_MISC: 'Miscellaneous commands',
     registrar.command.CATEGORY_NONE: 'Uncategorized commands',
 }
 
 # Topic categories.
 TOPIC_CATEGORY_IDS = 'ids'
 TOPIC_CATEGORY_OUTPUT = 'output'
 TOPIC_CATEGORY_CONFIG = 'config'
 TOPIC_CATEGORY_CONCEPTS = 'concepts'
 TOPIC_CATEGORY_MISC = 'misc'
 TOPIC_CATEGORY_NONE = 'none'
 
 # The order in which topic categories will be displayed.
 # Extensions with custom categories should insert them into this list
 # after/before the appropriate item, rather than replacing the list or
 # assuming absolute positions.
 TOPIC_CATEGORY_ORDER = [
     TOPIC_CATEGORY_IDS,
     TOPIC_CATEGORY_OUTPUT,
     TOPIC_CATEGORY_CONFIG,
     TOPIC_CATEGORY_CONCEPTS,
     TOPIC_CATEGORY_MISC,
     TOPIC_CATEGORY_NONE,
 ]
 
 # Human-readable topic category names. These are translated.
 TOPIC_CATEGORY_NAMES = {
     TOPIC_CATEGORY_IDS: 'Mercurial identifiers',
     TOPIC_CATEGORY_OUTPUT: 'Mercurial output',
     TOPIC_CATEGORY_CONFIG: 'Mercurial configuration',
     TOPIC_CATEGORY_CONCEPTS: 'Concepts',
     TOPIC_CATEGORY_MISC: 'Miscellaneous',
     TOPIC_CATEGORY_NONE: 'Uncategorized topics',
 }
 
 def listexts(header, exts, indent=1, showdeprecated=False):
     '''return a text listing of the given extensions'''
     rst = []
     if exts:
         for name, desc in sorted(exts.iteritems()):
             if not showdeprecated and any(w in desc for w in _exclkeywords):
                 continue
             rst.append('%s:%s: %s\n' % (' ' * indent, name, desc))
     if rst:
         rst.insert(0, '\n%s\n\n' % header)
     return rst
 
 def extshelp(ui):
     rst = loaddoc('extensions')(ui).splitlines(True)
     rst.extend(listexts(
         _('enabled extensions:'), extensions.enabled(), showdeprecated=True))
     rst.extend(listexts(_('disabled extensions:'), extensions.disabled(),
                         showdeprecated=ui.verbose))
     doc = ''.join(rst)
     return doc
 
 def optrst(header, options, verbose):
     data = []
     multioccur = False
     for option in options:
         if len(option) == 5:
             shortopt, longopt, default, desc, optlabel = option
         else:
             shortopt, longopt, default, desc = option
             optlabel = _("VALUE") # default label
 
         if not verbose and any(w in desc for w in _exclkeywords):
             continue
 
         so = ''
         if shortopt:
             so = '-' + shortopt
         lo = '--' + longopt
         if default is True:
             lo = '--[no-]' + longopt
 
         if isinstance(default, fancyopts.customopt):
             default = default.getdefaultvalue()
         if default and not callable(default):
             # default is of unknown type, and in Python 2 we abused
             # the %s-shows-repr property to handle integers etc. To
             # match that behavior on Python 3, we do str(default) and
             # then convert it to bytes.
             defaultstr = pycompat.bytestr(default)
             if default is True:
                 defaultstr = _("on")
             desc += _(" (default: %s)") % defaultstr
 
         if isinstance(default, list):
             lo += " %s [+]" % optlabel
             multioccur = True
         elif (default is not None) and not isinstance(default, bool):
             lo += " %s" % optlabel
 
         data.append((so, lo, desc))
 
     if multioccur:
         header += (_(" ([+] can be repeated)"))
 
     rst = ['\n%s:\n\n' % header]
     rst.extend(minirst.maketable(data, 1))
 
     return ''.join(rst)
 
 def indicateomitted(rst, omitted, notomitted=None):
     rst.append('\n\n.. container:: omitted\n\n    %s\n\n' % omitted)
     if notomitted:
         rst.append('\n\n.. container:: notomitted\n\n    %s\n\n' % notomitted)
 
 def filtercmd(ui, cmd, func, kw, doc):
     if not ui.debugflag and cmd.startswith("debug") and kw != "debug":
         # Debug command, and user is not looking for those.
         return True
     if not ui.verbose:
         if not kw and not doc:
             # Command had no documentation, no point in showing it by default.
             return True
         if getattr(func, 'alias', False) and not getattr(func, 'owndoc', False):
             # Alias didn't have its own documentation.
             return True
         if doc and any(w in doc for w in _exclkeywords):
             # Documentation has excluded keywords.
             return True
     if kw == "shortlist" and not getattr(func, 'helpbasic', False):
         # We're presenting the short list but the command is not basic.
         return True
     if ui.configbool('help', 'hidden-command.%s' % cmd):
         # Configuration explicitly hides the command.
         return True
     return False
 
 def filtertopic(ui, topic):
     return ui.configbool('help', 'hidden-topic.%s' % topic, False)
 
 def topicmatch(ui, commands, kw):
     """Return help topics matching kw.
 
     Returns {'section': [(name, summary), ...], ...} where section is
     one of topics, commands, extensions, or extensioncommands.
     """
     kw = encoding.lower(kw)
     def lowercontains(container):
         return kw in encoding.lower(container)  # translated in helptable
     results = {'topics': [],
                'commands': [],
                'extensions': [],
                'extensioncommands': [],
                }
     for topic in helptable:
         names, header, doc = topic[0:3]
         # Old extensions may use a str as doc.
         if (sum(map(lowercontains, names))
             or lowercontains(header)
             or (callable(doc) and lowercontains(doc(ui)))):
             name = names[0]
             if not filtertopic(ui, name):
                 results['topics'].append((names[0], header))
     for cmd, entry in commands.table.iteritems():
         if len(entry) == 3:
             summary = entry[2]
         else:
             summary = ''
         # translate docs *before* searching there
         func = entry[0]
         docs = _(pycompat.getdoc(func)) or ''
         if kw in cmd or lowercontains(summary) or lowercontains(docs):
             doclines = docs.splitlines()
             if doclines:
                 summary = doclines[0]
             cmdname = cmdutil.parsealiases(cmd)[0]
             if filtercmd(ui, cmdname, func, kw, docs):
                 continue
             results['commands'].append((cmdname, summary))
     for name, docs in itertools.chain(
         extensions.enabled(False).iteritems(),
         extensions.disabled().iteritems()):
         if not docs:
             continue
         name = name.rpartition('.')[-1]
         if lowercontains(name) or lowercontains(docs):
             # extension docs are already translated
             results['extensions'].append((name, docs.splitlines()[0]))
         try:
             mod = extensions.load(ui, name, '')
         except ImportError:
             # debug message would be printed in extensions.load()
             continue
         for cmd, entry in getattr(mod, 'cmdtable', {}).iteritems():
             if kw in cmd or (len(entry) > 2 and lowercontains(entry[2])):
                 cmdname = cmdutil.parsealiases(cmd)[0]
                 func = entry[0]
                 cmddoc = pycompat.getdoc(func)
                 if cmddoc:
                     cmddoc = gettext(cmddoc).splitlines()[0]
                 else:
                     cmddoc = _('(no help text available)')
                 if filtercmd(ui, cmdname, func, kw, cmddoc):
                     continue
                 results['extensioncommands'].append((cmdname, cmddoc))
     return results
 
 def loaddoc(topic, subdir=None):
     """Return a delayed loader for help/topic.txt."""
 
     def loader(ui):
         docdir = os.path.join(util.datapath, 'help')
         if subdir:
             docdir = os.path.join(docdir, subdir)
         path = os.path.join(docdir, topic + ".txt")
         doc = gettext(util.readfile(path))
         for rewriter in helphooks.get(topic, []):
             doc = rewriter(ui, topic, doc)
         return doc
 
     return loader
 
 internalstable = sorted([
     (['bundle2'], _('Bundle2'),
      loaddoc('bundle2', subdir='internals')),
     (['bundles'], _('Bundles'),
      loaddoc('bundles', subdir='internals')),
     (['cbor'], _('CBOR'),
      loaddoc('cbor', subdir='internals')),
     (['censor'], _('Censor'),
      loaddoc('censor', subdir='internals')),
     (['changegroups'], _('Changegroups'),
      loaddoc('changegroups', subdir='internals')),
     (['config'], _('Config Registrar'),
      loaddoc('config', subdir='internals')),
     (['extensions', 'extension'], _('Extension API'),
      loaddoc('extensions', subdir='internals')),
     (['requirements'], _('Repository Requirements'),
      loaddoc('requirements', subdir='internals')),
     (['revlogs'], _('Revision Logs'),
      loaddoc('revlogs', subdir='internals')),
     (['wireprotocol'], _('Wire Protocol'),
      loaddoc('wireprotocol', subdir='internals')),
     (['wireprotocolrpc'], _('Wire Protocol RPC'),
      loaddoc('wireprotocolrpc', subdir='internals')),
     (['wireprotocolv2'], _('Wire Protocol Version 2'),
      loaddoc('wireprotocolv2', subdir='internals')),
 ])
 
 def internalshelp(ui):
     """Generate the index for the "internals" topic."""
     lines = ['To access a subtopic, use "hg help internals.{subtopic-name}"\n',
              '\n']
     for names, header, doc in internalstable:
         lines.append(' :%s: %s\n' % (names[0], header))
 
     return ''.join(lines)
 
 helptable = sorted([
     (['bundlespec'], _("Bundle File Formats"), loaddoc('bundlespec'),
      TOPIC_CATEGORY_CONCEPTS),
     (['color'], _("Colorizing Outputs"), loaddoc('color'),
      TOPIC_CATEGORY_OUTPUT),
     (["config", "hgrc"], _("Configuration Files"), loaddoc('config'),
      TOPIC_CATEGORY_CONFIG),
     (['deprecated'], _("Deprecated Features"), loaddoc('deprecated'),
      TOPIC_CATEGORY_MISC),
     (["dates"], _("Date Formats"), loaddoc('dates'), TOPIC_CATEGORY_OUTPUT),
     (["flags"], _("Command-line flags"), loaddoc('flags'),
      TOPIC_CATEGORY_CONFIG),
     (["patterns"], _("File Name Patterns"), loaddoc('patterns'),
      TOPIC_CATEGORY_IDS),
     (['environment', 'env'], _('Environment Variables'),
      loaddoc('environment'), TOPIC_CATEGORY_CONFIG),
     (['revisions', 'revs', 'revsets', 'revset', 'multirevs', 'mrevs'],
       _('Specifying Revisions'), loaddoc('revisions'), TOPIC_CATEGORY_IDS),
     (['filesets', 'fileset'], _("Specifying File Sets"), loaddoc('filesets'),
      TOPIC_CATEGORY_IDS),
     (['diffs'], _('Diff Formats'), loaddoc('diffs'), TOPIC_CATEGORY_OUTPUT),
     (['merge-tools', 'mergetools', 'mergetool'], _('Merge Tools'),
      loaddoc('merge-tools'), TOPIC_CATEGORY_CONFIG),
     (['templating', 'templates', 'template', 'style'], _('Template Usage'),
      loaddoc('templates'), TOPIC_CATEGORY_OUTPUT),
     (['urls'], _('URL Paths'), loaddoc('urls'), TOPIC_CATEGORY_IDS),
     (["extensions"], _("Using Additional Features"), extshelp,
      TOPIC_CATEGORY_CONFIG),
     (["subrepos", "subrepo"], _("Subrepositories"), loaddoc('subrepos'),
      TOPIC_CATEGORY_CONCEPTS),
     (["hgweb"], _("Configuring hgweb"), loaddoc('hgweb'),
      TOPIC_CATEGORY_CONFIG),
     (["glossary"], _("Glossary"), loaddoc('glossary'), TOPIC_CATEGORY_CONCEPTS),
     (["hgignore", "ignore"], _("Syntax for Mercurial Ignore Files"),
      loaddoc('hgignore'), TOPIC_CATEGORY_IDS),
     (["phases"], _("Working with Phases"), loaddoc('phases'),
      TOPIC_CATEGORY_CONCEPTS),
     (['scripting'], _('Using Mercurial from scripts and automation'),
      loaddoc('scripting'), TOPIC_CATEGORY_MISC),
     (['internals'], _("Technical implementation topics"), internalshelp,
      TOPIC_CATEGORY_MISC),
     (['pager'], _("Pager Support"), loaddoc('pager'), TOPIC_CATEGORY_CONFIG),
 ])
 
 # Maps topics with sub-topics to a list of their sub-topics.
 subtopics = {
     'internals': internalstable,
 }
 
 # Map topics to lists of callable taking the current topic help and
 # returning the updated version
 helphooks = {}
 
 def addtopichook(topic, rewriter):
     helphooks.setdefault(topic, []).append(rewriter)
 
 def makeitemsdoc(ui, topic, doc, marker, items, dedent=False):
     """Extract docstring from the items key to function mapping, build a
     single documentation block and use it to overwrite the marker in doc.
     """
     entries = []
     for name in sorted(items):
         text = (pycompat.getdoc(items[name]) or '').rstrip()
         if (not text
             or not ui.verbose and any(w in text for w in _exclkeywords)):
             continue
         text = gettext(text)
         if dedent:
             # Abuse latin1 to use textwrap.dedent() on bytes.
             text = textwrap.dedent(text.decode('latin1')).encode('latin1')
         lines = text.splitlines()
         doclines = [(lines[0])]
         for l in lines[1:]:
             # Stop once we find some Python doctest
             if l.strip().startswith('>>>'):
                 break
             if dedent:
                 doclines.append(l.rstrip())
             else:
                 doclines.append('  ' + l.strip())
         entries.append('\n'.join(doclines))
     entries = '\n\n'.join(entries)
     return doc.replace(marker, entries)
 
 def addtopicsymbols(topic, marker, symbols, dedent=False):
     def add(ui, topic, doc):
         return makeitemsdoc(ui, topic, doc, marker, symbols, dedent=dedent)
     addtopichook(topic, add)
 
 addtopicsymbols('bundlespec', '.. bundlecompressionmarker',
                 compression.bundlecompressiontopics())
 addtopicsymbols('filesets', '.. predicatesmarker', fileset.symbols)
 addtopicsymbols('merge-tools', '.. internaltoolsmarker',
                 filemerge.internalsdoc)
 addtopicsymbols('revisions', '.. predicatesmarker', revset.symbols)
 addtopicsymbols('templates', '.. keywordsmarker', templatekw.keywords)
 addtopicsymbols('templates', '.. filtersmarker', templatefilters.filters)
 addtopicsymbols('templates', '.. functionsmarker', templatefuncs.funcs)
 addtopicsymbols('hgweb', '.. webcommandsmarker', webcommands.commands,
                 dedent=True)
 
 def inserttweakrc(ui, topic, doc):
     marker = '.. tweakdefaultsmarker'
     repl = uimod.tweakrc
     def sub(m):
         lines = [m.group(1) + s for s in repl.splitlines()]
         return '\n'.join(lines)
     return re.sub(br'( *)%s' % re.escape(marker), sub, doc)
 
 addtopichook('config', inserttweakrc)
 
 def help_(ui, commands, name, unknowncmd=False, full=True, subtopic=None,
           **opts):
     '''
     Generate the help for 'name' as unformatted restructured text. If
     'name' is None, describe the commands available.
     '''
 
     opts = pycompat.byteskwargs(opts)
 
     def helpcmd(name, subtopic=None):
         try:
             aliases, entry = cmdutil.findcmd(name, commands.table,
                                              strict=unknowncmd)
         except error.AmbiguousCommand as inst:
             # py3 fix: except vars can't be used outside the scope of the
             # except block, nor can be used inside a lambda. python issue4617
             prefix = inst.args[0]
             select = lambda c: cmdutil.parsealiases(c)[0].startswith(prefix)
             rst = helplist(select)
             return rst
 
         rst = []
 
         # check if it's an invalid alias and display its error if it is
         if getattr(entry[0], 'badalias', None):
             rst.append(entry[0].badalias + '\n')
             if entry[0].unknowncmd:
                 try:
                     rst.extend(helpextcmd(entry[0].cmdname))
                 except error.UnknownCommand:
                     pass
             return rst
 
         # synopsis
         if len(entry) > 2:
             if entry[2].startswith('hg'):
                 rst.append("%s\n" % entry[2])
             else:
                 rst.append('hg %s %s\n' % (aliases[0], entry[2]))
         else:
             rst.append('hg %s\n' % aliases[0])
         # aliases
         if full and not ui.quiet and len(aliases) > 1:
             rst.append(_("\naliases: %s\n") % ', '.join(aliases[1:]))
         rst.append('\n')
 
         # description
         doc = gettext(pycompat.getdoc(entry[0]))
         if not doc:
             doc = _("(no help text available)")
         if util.safehasattr(entry[0], 'definition'):  # aliased command
             source = entry[0].source
             if entry[0].definition.startswith('!'):  # shell alias
                 doc = (_('shell alias for: %s\n\n%s\n\ndefined by: %s\n') %
                        (entry[0].definition[1:], doc, source))
             else:
                 doc = (_('alias for: hg %s\n\n%s\n\ndefined by: %s\n') %
                        (entry[0].definition, doc, source))
         doc = doc.splitlines(True)
         if ui.quiet or not full:
             rst.append(doc[0])
         else:
             rst.extend(doc)
         rst.append('\n')
 
         # check if this command shadows a non-trivial (multi-line)
         # extension help text
         try:
             mod = extensions.find(name)
             doc = gettext(pycompat.getdoc(mod)) or ''
             if '\n' in doc.strip():
                 msg = _("(use 'hg help -e %s' to show help for "
                         "the %s extension)") % (name, name)
                 rst.append('\n%s\n' % msg)
         except KeyError:
             pass
 
         # options
         if not ui.quiet and entry[1]:
             rst.append(optrst(_("options"), entry[1], ui.verbose))
 
         if ui.verbose:
             rst.append(optrst(_("global options"),
                               commands.globalopts, ui.verbose))
 
         if not ui.verbose:
             if not full:
                 rst.append(_("\n(use 'hg %s -h' to show more help)\n")
                            % name)
             elif not ui.quiet:
                 rst.append(_('\n(some details hidden, use --verbose '
                                'to show complete help)'))
 
         return rst
 
     def helplist(select=None, **opts):
         # Category -> list of commands
         cats = {}
         # Command -> short description
         h = {}
         # Command -> string showing synonyms
         syns = {}
         for c, e in commands.table.iteritems():
             fs = cmdutil.parsealiases(c)
             f = fs[0]
             syns[f] = ', '.join(fs)
             func = e[0]
             if select and not select(f):
                 continue
             doc = pycompat.getdoc(func)
             if filtercmd(ui, f, func, name, doc):
                 continue
             doc = gettext(doc)
             if not doc:
                 doc = _("(no help text available)")
             h[f] = doc.splitlines()[0].rstrip()
 
             cat = getattr(func, 'helpcategory', None) or (
                 registrar.command.CATEGORY_NONE)
             cats.setdefault(cat, []).append(f)
 
         rst = []
         if not h:
             if not ui.quiet:
                 rst.append(_('no commands defined\n'))
             return rst
 
         # Output top header.
         if not ui.quiet:
             if name == "shortlist":
                 rst.append(_('basic commands:\n\n'))
             elif name == "debug":
                 rst.append(_('debug commands (internal and unsupported):\n\n'))
             else:
                 rst.append(_('list of commands:\n'))
 
         def appendcmds(cmds):
             cmds = sorted(cmds)
             for c in cmds:
                 if ui.verbose:
                     rst.append(" :%s: %s\n" % (syns[c], h[c]))
                 else:
                     rst.append(' :%s: %s\n' % (c, h[c]))
 
         if name in ('shortlist', 'debug'):
             # List without categories.
             appendcmds(h)
         else:
             # Check that all categories have an order.
             missing_order = set(cats.keys()) - set(CATEGORY_ORDER)
             if missing_order:
                 ui.develwarn('help categories missing from CATEGORY_ORDER: %s' %
                              missing_order)
 
             # List per category.
             for cat in CATEGORY_ORDER:
                 catfns = cats.get(cat, [])
                 if catfns:
                     if len(cats) > 1:
                         catname = gettext(CATEGORY_NAMES[cat])
                         rst.append("\n%s:\n" % catname)
                     rst.append("\n")
                     appendcmds(catfns)
 
         ex = opts.get
         anyopts = (ex(r'keyword') or not (ex(r'command') or ex(r'extension')))
         if not name and anyopts:
             exts = listexts(_('enabled extensions:'), extensions.enabled(),
                             showdeprecated=ui.verbose)
             if exts:
                 rst.append('\n')
                 rst.extend(exts)
 
             rst.append(_("\nadditional help topics:\n"))
             # Group commands by category.
             topiccats = {}
             for topic in helptable:
                 names, header, doc = topic[0:3]
                 if len(topic) > 3 and topic[3]:
                     category = topic[3]
                 else:
                     category = TOPIC_CATEGORY_NONE
 
                 topicname = names[0]
                 if not filtertopic(ui, topicname):
                     topiccats.setdefault(category, []).append(
                         (topicname, header))
 
             # Check that all categories have an order.
             missing_order = set(topiccats.keys()) - set(TOPIC_CATEGORY_ORDER)
             if missing_order:
                 ui.develwarn(
                     'help categories missing from TOPIC_CATEGORY_ORDER: %s' %
                     missing_order)
 
             # Output topics per category.
             for cat in TOPIC_CATEGORY_ORDER:
                 topics = topiccats.get(cat, [])
                 if topics:
                     if len(topiccats) > 1:
                         catname = gettext(TOPIC_CATEGORY_NAMES[cat])
                         rst.append("\n%s:\n" % catname)
                     rst.append("\n")
                     for t, desc in topics:
                         rst.append(" :%s: %s\n" % (t, desc))
 
         if ui.quiet:
             pass
         elif ui.verbose:
             rst.append('\n%s\n' % optrst(_("global options"),
                                          commands.globalopts, ui.verbose))
             if name == 'shortlist':
                 rst.append(_("\n(use 'hg help' for the full list "
                              "of commands)\n"))
         else:
             if name == 'shortlist':
                 rst.append(_("\n(use 'hg help' for the full list of commands "
                              "or 'hg -v' for details)\n"))
             elif name and not full:
                 rst.append(_("\n(use 'hg help %s' to show the full help "
                              "text)\n") % name)
             elif name and syns and name in syns.keys():
                 rst.append(_("\n(use 'hg help -v -e %s' to show built-in "
                              "aliases and global options)\n") % name)
             else:
                 rst.append(_("\n(use 'hg help -v%s' to show built-in aliases "
                              "and global options)\n")
                            % (name and " " + name or ""))
         return rst
 
     def helptopic(name, subtopic=None):
         # Look for sub-topic entry first.
         header, doc = None, None
         if subtopic and name in subtopics:
             for names, header, doc in subtopics[name]:
                 if subtopic in names:
                     break
+            if not any(subtopic in s[0] for s in subtopics[name]):
+                raise error.UnknownCommand(name)
 
         if not header:
             for topic in helptable:
                 names, header, doc = topic[0:3]
                 if name in names:
                     break
             else:
                 raise error.UnknownCommand(name)
 
         rst = [minirst.section(header)]
 
         # description
         if not doc:
             rst.append("    %s\n" % _("(no help text available)"))
         if callable(doc):
             rst += ["    %s\n" % l for l in doc(ui).splitlines()]
 
         if not ui.verbose:
             omitted = _('(some details hidden, use --verbose'
                          ' to show complete help)')
             indicateomitted(rst, omitted)
 
         try:
             cmdutil.findcmd(name, commands.table)
             rst.append(_("\nuse 'hg help -c %s' to see help for "
                        "the %s command\n") % (name, name))
         except error.UnknownCommand:
             pass
         return rst
 
     def helpext(name, subtopic=None):
         try:
             mod = extensions.find(name)
             doc = gettext(pycompat.getdoc(mod)) or _('no help text available')
         except KeyError:
             mod = None
             doc = extensions.disabledext(name)
             if not doc:
                 raise error.UnknownCommand(name)
 
         if '\n' not in doc:
             head, tail = doc, ""
         else:
             head, tail = doc.split('\n', 1)
         rst = [_('%s extension - %s\n\n') % (name.rpartition('.')[-1], head)]
         if tail:
             rst.extend(tail.splitlines(True))
             rst.append('\n')
 
         if not ui.verbose:
             omitted = _('(some details hidden, use --verbose'
                          ' to show complete help)')
             indicateomitted(rst, omitted)
 
         if mod:
             try:
                 ct = mod.cmdtable
             except AttributeError:
                 ct = {}
             modcmds = {c.partition('|')[0] for c in ct}
             rst.extend(helplist(modcmds.__contains__))
         else:
             rst.append(_("(use 'hg help extensions' for information on enabling"
                        " extensions)\n"))
         return rst
 
     def helpextcmd(name, subtopic=None):
         cmd, ext, doc = extensions.disabledcmd(ui, name,
                                                ui.configbool('ui', 'strict'))
         doc = doc.splitlines()[0]
 
         rst = listexts(_("'%s' is provided by the following "
                               "extension:") % cmd, {ext: doc}, indent=4,
                        showdeprecated=True)
         rst.append('\n')
         rst.append(_("(use 'hg help extensions' for information on enabling "
                    "extensions)\n"))
         return rst
 
 
     rst = []
     kw = opts.get('keyword')
     if kw or name is None and any(opts[o] for o in opts):
         matches = topicmatch(ui, commands, name or '')
         helpareas = []
         if opts.get('extension'):
             helpareas += [('extensions', _('Extensions'))]
         if opts.get('command'):
             helpareas += [('commands', _('Commands'))]
         if not helpareas:
             helpareas = [('topics', _('Topics')),
                          ('commands', _('Commands')),
                          ('extensions', _('Extensions')),
                          ('extensioncommands', _('Extension Commands'))]
         for t, title in helpareas:
             if matches[t]:
                 rst.append('%s:\n\n' % title)
                 rst.extend(minirst.maketable(sorted(matches[t]), 1))
                 rst.append('\n')
         if not rst:
             msg = _('no matches')
             hint = _("try 'hg help' for a list of topics")
             raise error.Abort(msg, hint=hint)
     elif name and name != 'shortlist':
         queries = []
         if unknowncmd:
             queries += [helpextcmd]
         if opts.get('extension'):
             queries += [helpext]
         if opts.get('command'):
             queries += [helpcmd]
         if not queries:
             queries = (helptopic, helpcmd, helpext, helpextcmd)
         for f in queries:
             try:
                 rst = f(name, subtopic)
                 break
             except error.UnknownCommand:
                 pass
         else:
             if unknowncmd:
                 raise error.UnknownCommand(name)
             else:
                 msg = _('no such help topic: %s') % name
                 hint = _("try 'hg help --keyword %s'") % name
                 raise error.Abort(msg, hint=hint)
     else:
         # program name
         if not ui.quiet:
             rst = [_("Mercurial Distributed SCM\n"), '\n']
         rst.extend(helplist(None, **pycompat.strkwargs(opts)))
 
     return ''.join(rst)
 
 def formattedhelp(ui, commands, fullname, keep=None, unknowncmd=False,
                   full=True, **opts):
     """get help for a given topic (as a dotted name) as rendered rst
 
     Either returns the rendered help text or raises an exception.
     """
     if keep is None:
         keep = []
     else:
         keep = list(keep) # make a copy so we can mutate this later
 
     # <fullname> := <name>[.<subtopic][.<section>]
     name = subtopic = section = None
     if fullname is not None:
         nameparts = fullname.split('.')
         name = nameparts.pop(0)
         if nameparts and name in subtopics:
             subtopic = nameparts.pop(0)
         if nameparts:
             section = encoding.lower('.'.join(nameparts))
 
     textwidth = ui.configint('ui', 'textwidth')
     termwidth = ui.termwidth() - 2
     if textwidth <= 0 or termwidth < textwidth:
         textwidth = termwidth
     text = help_(ui, commands, name,
                  subtopic=subtopic, unknowncmd=unknowncmd, full=full, **opts)
 
     blocks, pruned = minirst.parse(text, keep=keep)
     if 'verbose' in pruned:
         keep.append('omitted')
     else:
         keep.append('notomitted')
     blocks, pruned = minirst.parse(text, keep=keep)
     if section:
         blocks = minirst.filtersections(blocks, section)
 
     # We could have been given a weird ".foo" section without a name
     # to look for, or we could have simply failed to found "foo.bar"
     # because bar isn't a section of foo
     if section and not (blocks and name):
         raise error.Abort(_("help section not found: %s") % fullname)
 
     return minirst.formatplain(blocks, textwidth)