extensions: catch uisetup and extsetup failures and don't let them break hg

Otherwise users of the patience diff extension will be unable to run
anything at all in hg 4.3 until they figure out what's broken.

mercurial/extensions.py

@@ -1,597 +1,619 b''
 # extensions.py - extension handling 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
 
 import imp
 import inspect
 import os
 
 from .i18n import (
     _,
     gettext,
 )
 
 from . import (
     cmdutil,
     encoding,
     error,
     pycompat,
     util,
 )
 
 _extensions = {}
 _disabledextensions = {}
 _aftercallbacks = {}
 _order = []
 _builtin = {'hbisect', 'bookmarks', 'parentrevspec', 'progress', 'interhg',
             'inotify', 'hgcia'}
 
 def extensions(ui=None):
     if ui:
         def enabled(name):
             for format in ['%s', 'hgext.%s']:
                 conf = ui.config('extensions', format % name)
                 if conf is not None and not conf.startswith('!'):
                     return True
     else:
         enabled = lambda name: True
     for name in _order:
         module = _extensions[name]
         if module and enabled(name):
             yield name, module
 
 def find(name):
     '''return module with given extension name'''
     mod = None
     try:
         mod = _extensions[name]
     except KeyError:
         for k, v in _extensions.iteritems():
             if k.endswith('.' + name) or k.endswith('/' + name):
                 mod = v
                 break
     if not mod:
         raise KeyError(name)
     return mod
 
 def loadpath(path, module_name):
     module_name = module_name.replace('.', '_')
     path = util.normpath(util.expandpath(path))
     module_name = pycompat.fsdecode(module_name)
     path = pycompat.fsdecode(path)
     if os.path.isdir(path):
         # module/__init__.py style
         d, f = os.path.split(path)
         fd, fpath, desc = imp.find_module(f, [d])
         return imp.load_module(module_name, fd, fpath, desc)
     else:
         try:
             return imp.load_source(module_name, path)
         except IOError as exc:
             if not exc.filename:
                 exc.filename = path # python does not fill this
             raise
 
 def _importh(name):
     """import and return the <name> module"""
     mod = __import__(pycompat.sysstr(name))
     components = name.split('.')
     for comp in components[1:]:
         mod = getattr(mod, comp)
     return mod
 
 def _importext(name, path=None, reportfunc=None):
     if path:
         # the module will be loaded in sys.modules
         # choose an unique name so that it doesn't
         # conflicts with other modules
         mod = loadpath(path, 'hgext.%s' % name)
     else:
         try:
             mod = _importh("hgext.%s" % name)
         except ImportError as err:
             if reportfunc:
                 reportfunc(err, "hgext.%s" % name, "hgext3rd.%s" % name)
             try:
                 mod = _importh("hgext3rd.%s" % name)
             except ImportError as err:
                 if reportfunc:
                     reportfunc(err, "hgext3rd.%s" % name, name)
                 mod = _importh(name)
     return mod
 
 def _forbytes(inst):
     """Portably format an import error into a form suitable for
     %-formatting into bytestrings."""
     return encoding.strtolocal(str(inst))
 
 def _reportimporterror(ui, err, failed, next):
     # note: this ui.debug happens before --debug is processed,
     #       Use --config ui.debug=1 to see them.
     ui.debug('could not import %s (%s): trying %s\n'
              % (failed, _forbytes(err), next))
     if ui.debugflag:
         ui.traceback()
 
 # attributes set by registrar.command
 _cmdfuncattrs = ('norepo', 'optionalrepo', 'inferrepo')
 
 def _validatecmdtable(ui, cmdtable):
     """Check if extension commands have required attributes"""
     for c, e in cmdtable.iteritems():
         f = e[0]
         if getattr(f, '_deprecatedregistrar', False):
             ui.deprecwarn("cmdutil.command is deprecated, use "
                           "registrar.command to register '%s'" % c, '4.6')
         missing = [a for a in _cmdfuncattrs if not util.safehasattr(f, a)]
         if not missing:
             continue
         raise error.ProgrammingError(
             'missing attributes: %s' % ', '.join(missing),
             hint="use @command decorator to register '%s'" % c)
 
 def load(ui, name, path):
     if name.startswith('hgext.') or name.startswith('hgext/'):
         shortname = name[6:]
     else:
         shortname = name
     if shortname in _builtin:
         return None
     if shortname in _extensions:
         return _extensions[shortname]
     _extensions[shortname] = None
     mod = _importext(name, path, bind(_reportimporterror, ui))
 
     # Before we do anything with the extension, check against minimum stated
     # compatibility. This gives extension authors a mechanism to have their
     # extensions short circuit when loaded with a known incompatible version
     # of Mercurial.
     minver = getattr(mod, 'minimumhgversion', None)
     if minver and util.versiontuple(minver, 2) > util.versiontuple(n=2):
         ui.warn(_('(third party extension %s requires version %s or newer '
                   'of Mercurial; disabling)\n') % (shortname, minver))
         return
     _validatecmdtable(ui, getattr(mod, 'cmdtable', {}))
 
     _extensions[shortname] = mod
     _order.append(shortname)
     for fn in _aftercallbacks.get(shortname, []):
         fn(loaded=True)
     return mod
 
 def _runuisetup(name, ui):
     uisetup = getattr(_extensions[name], 'uisetup', None)
     if uisetup:
-        uisetup(ui)
+        try:
+            uisetup(ui)
+        except Exception as inst:
+            ui.traceback()
+            msg = _forbytes(inst)
+            ui.warn(_("*** failed to set up extension %s: %s\n") % (name, msg))
+            return False
+    return True
 
 def _runextsetup(name, ui):
     extsetup = getattr(_extensions[name], 'extsetup', None)
     if extsetup:
         try:
-            extsetup(ui)
-        except TypeError:
-            if inspect.getargspec(extsetup).args:
-                raise
-            extsetup() # old extsetup with no ui argument
+            try:
+                extsetup(ui)
+            except TypeError:
+                if inspect.getargspec(extsetup).args:
+                    raise
+                extsetup() # old extsetup with no ui argument
+        except Exception as inst:
+            ui.traceback()
+            msg = _forbytes(inst)
+            ui.warn(_("*** failed to set up extension %s: %s\n") % (name, msg))
+            return False
+    return True
 
 def loadall(ui, whitelist=None):
     result = ui.configitems("extensions")
     if whitelist is not None:
         result = [(k, v) for (k, v) in result if k in whitelist]
     newindex = len(_order)
     for (name, path) in result:
         if path:
             if path[0:1] == '!':
                 _disabledextensions[name] = path[1:]
                 continue
         try:
             load(ui, name, path)
         except Exception as inst:
             msg = _forbytes(inst)
             if path:
                 ui.warn(_("*** failed to import extension %s from %s: %s\n")
                         % (name, path, msg))
             else:
                 ui.warn(_("*** failed to import extension %s: %s\n")
                         % (name, msg))
             if isinstance(inst, error.Hint) and inst.hint:
                 ui.warn(_("*** (%s)\n") % inst.hint)
             ui.traceback()
 
+    broken = set()
     for name in _order[newindex:]:
-        _runuisetup(name, ui)
+        if not _runuisetup(name, ui):
+            broken.add(name)
 
     for name in _order[newindex:]:
-        _runextsetup(name, ui)
+        if name in broken:
+            continue
+        if not _runextsetup(name, ui):
+            broken.add(name)
+
+    for name in broken:
+        _extensions[name] = None
 
     # Call aftercallbacks that were never met.
     for shortname in _aftercallbacks:
         if shortname in _extensions:
             continue
 
         for fn in _aftercallbacks[shortname]:
             fn(loaded=False)
 
     # loadall() is called multiple times and lingering _aftercallbacks
     # entries could result in double execution. See issue4646.
     _aftercallbacks.clear()
 
 def afterloaded(extension, callback):
     '''Run the specified function after a named extension is loaded.
 
     If the named extension is already loaded, the callback will be called
     immediately.
 
     If the named extension never loads, the callback will be called after
     all extensions have been loaded.
 
     The callback receives the named argument ``loaded``, which is a boolean
     indicating whether the dependent extension actually loaded.
     '''
 
     if extension in _extensions:
         callback(loaded=True)
     else:
         _aftercallbacks.setdefault(extension, []).append(callback)
 
 def bind(func, *args):
     '''Partial function application
 
       Returns a new function that is the partial application of args and kwargs
       to func.  For example,
 
           f(1, 2, bar=3) === bind(f, 1)(2, bar=3)'''
     assert callable(func)
     def closure(*a, **kw):
         return func(*(args + a), **kw)
     return closure
 
 def _updatewrapper(wrap, origfn, unboundwrapper):
     '''Copy and add some useful attributes to wrapper'''
     wrap.__module__ = getattr(origfn, '__module__')
     wrap.__doc__ = getattr(origfn, '__doc__')
     wrap.__dict__.update(getattr(origfn, '__dict__', {}))
     wrap._origfunc = origfn
     wrap._unboundwrapper = unboundwrapper
 
 def wrapcommand(table, command, wrapper, synopsis=None, docstring=None):
     '''Wrap the command named `command' in table
 
     Replace command in the command table with wrapper. The wrapped command will
     be inserted into the command table specified by the table argument.
 
     The wrapper will be called like
 
       wrapper(orig, *args, **kwargs)
 
     where orig is the original (wrapped) function, and *args, **kwargs
     are the arguments passed to it.
 
     Optionally append to the command synopsis and docstring, used for help.
     For example, if your extension wraps the ``bookmarks`` command to add the
     flags ``--remote`` and ``--all`` you might call this function like so:
 
       synopsis = ' [-a] [--remote]'
       docstring = """
 
       The ``remotenames`` extension adds the ``--remote`` and ``--all`` (``-a``)
       flags to the bookmarks command. Either flag will show the remote bookmarks
       known to the repository; ``--remote`` will also suppress the output of the
       local bookmarks.
       """
 
       extensions.wrapcommand(commands.table, 'bookmarks', exbookmarks,
                              synopsis, docstring)
     '''
     assert callable(wrapper)
     aliases, entry = cmdutil.findcmd(command, table)
     for alias, e in table.iteritems():
         if e is entry:
             key = alias
             break
 
     origfn = entry[0]
     wrap = bind(util.checksignature(wrapper), util.checksignature(origfn))
     _updatewrapper(wrap, origfn, wrapper)
     if docstring is not None:
         wrap.__doc__ += docstring
 
     newentry = list(entry)
     newentry[0] = wrap
     if synopsis is not None:
         newentry[2] += synopsis
     table[key] = tuple(newentry)
     return entry
 
 def wrapfilecache(cls, propname, wrapper):
     """Wraps a filecache property.
 
     These can't be wrapped using the normal wrapfunction.
     """
     assert callable(wrapper)
     for currcls in cls.__mro__:
         if propname in currcls.__dict__:
             origfn = currcls.__dict__[propname].func
             assert callable(origfn)
             def wrap(*args, **kwargs):
                 return wrapper(origfn, *args, **kwargs)
             currcls.__dict__[propname].func = wrap
             break
 
     if currcls is object:
         raise AttributeError(
             _("type '%s' has no property '%s'") % (cls, propname))
 
 def wrapfunction(container, funcname, wrapper):
     '''Wrap the function named funcname in container
 
     Replace the funcname member in the given container with the specified
     wrapper. The container is typically a module, class, or instance.
 
     The wrapper will be called like
 
       wrapper(orig, *args, **kwargs)
 
     where orig is the original (wrapped) function, and *args, **kwargs
     are the arguments passed to it.
 
     Wrapping methods of the repository object is not recommended since
     it conflicts with extensions that extend the repository by
     subclassing. All extensions that need to extend methods of
     localrepository should use this subclassing trick: namely,
     reposetup() should look like
 
       def reposetup(ui, repo):
           class myrepo(repo.__class__):
               def whatever(self, *args, **kwargs):
                   [...extension stuff...]
                   super(myrepo, self).whatever(*args, **kwargs)
                   [...extension stuff...]
 
           repo.__class__ = myrepo
 
     In general, combining wrapfunction() with subclassing does not
     work. Since you cannot control what other extensions are loaded by
     your end users, you should play nicely with others by using the
     subclass trick.
     '''
     assert callable(wrapper)
 
     origfn = getattr(container, funcname)
     assert callable(origfn)
     wrap = bind(wrapper, origfn)
     _updatewrapper(wrap, origfn, wrapper)
     setattr(container, funcname, wrap)
     return origfn
 
 def unwrapfunction(container, funcname, wrapper=None):
     '''undo wrapfunction
 
     If wrappers is None, undo the last wrap. Otherwise removes the wrapper
     from the chain of wrappers.
 
     Return the removed wrapper.
     Raise IndexError if wrapper is None and nothing to unwrap; ValueError if
     wrapper is not None but is not found in the wrapper chain.
     '''
     chain = getwrapperchain(container, funcname)
     origfn = chain.pop()
     if wrapper is None:
         wrapper = chain[0]
     chain.remove(wrapper)
     setattr(container, funcname, origfn)
     for w in reversed(chain):
         wrapfunction(container, funcname, w)
     return wrapper
 
 def getwrapperchain(container, funcname):
     '''get a chain of wrappers of a function
 
     Return a list of functions: [newest wrapper, ..., oldest wrapper, origfunc]
 
     The wrapper functions are the ones passed to wrapfunction, whose first
     argument is origfunc.
     '''
     result = []
     fn = getattr(container, funcname)
     while fn:
         assert callable(fn)
         result.append(getattr(fn, '_unboundwrapper', fn))
         fn = getattr(fn, '_origfunc', None)
     return result
 
 def _disabledpaths(strip_init=False):
     '''find paths of disabled extensions. returns a dict of {name: path}
     removes /__init__.py from packages if strip_init is True'''
     import hgext
     extpath = os.path.dirname(
         os.path.abspath(pycompat.fsencode(hgext.__file__)))
     try: # might not be a filesystem path
         files = os.listdir(extpath)
     except OSError:
         return {}
 
     exts = {}
     for e in files:
         if e.endswith('.py'):
             name = e.rsplit('.', 1)[0]
             path = os.path.join(extpath, e)
         else:
             name = e
             path = os.path.join(extpath, e, '__init__.py')
             if not os.path.exists(path):
                 continue
             if strip_init:
                 path = os.path.dirname(path)
         if name in exts or name in _order or name == '__init__':
             continue
         exts[name] = path
     exts.update(_disabledextensions)
     return exts
 
 def _moduledoc(file):
     '''return the top-level python documentation for the given file
 
     Loosely inspired by pydoc.source_synopsis(), but rewritten to
     handle triple quotes and to return the whole text instead of just
     the synopsis'''
     result = []
 
     line = file.readline()
     while line[:1] == '#' or not line.strip():
         line = file.readline()
         if not line:
             break
 
     start = line[:3]
     if start == '"""' or start == "'''":
         line = line[3:]
         while line:
             if line.rstrip().endswith(start):
                 line = line.split(start)[0]
                 if line:
                     result.append(line)
                 break
             elif not line:
                 return None # unmatched delimiter
             result.append(line)
             line = file.readline()
     else:
         return None
 
     return ''.join(result)
 
 def _disabledhelp(path):
     '''retrieve help synopsis of a disabled extension (without importing)'''
     try:
         file = open(path)
     except IOError:
         return
     else:
         doc = _moduledoc(file)
         file.close()
 
     if doc: # extracting localized synopsis
         return gettext(doc)
     else:
         return _('(no help text available)')
 
 def disabled():
     '''find disabled extensions from hgext. returns a dict of {name: desc}'''
     try:
         from hgext import __index__
         return dict((name, gettext(desc))
                     for name, desc in __index__.docs.iteritems()
                     if name not in _order)
     except (ImportError, AttributeError):
         pass
 
     paths = _disabledpaths()
     if not paths:
         return {}
 
     exts = {}
     for name, path in paths.iteritems():
         doc = _disabledhelp(path)
         if doc:
             exts[name] = doc.splitlines()[0]
 
     return exts
 
 def disabledext(name):
     '''find a specific disabled extension from hgext. returns desc'''
     try:
         from hgext import __index__
         if name in _order:  # enabled
             return
         else:
             return gettext(__index__.docs.get(name))
     except (ImportError, AttributeError):
         pass
 
     paths = _disabledpaths()
     if name in paths:
         return _disabledhelp(paths[name])
 
 def disabledcmd(ui, cmd, strict=False):
     '''import disabled extensions until cmd is found.
     returns (cmdname, extname, module)'''
 
     paths = _disabledpaths(strip_init=True)
     if not paths:
         raise error.UnknownCommand(cmd)
 
     def findcmd(cmd, name, path):
         try:
             mod = loadpath(path, 'hgext.%s' % name)
         except Exception:
             return
         try:
             aliases, entry = cmdutil.findcmd(cmd,
                 getattr(mod, 'cmdtable', {}), strict)
         except (error.AmbiguousCommand, error.UnknownCommand):
             return
         except Exception:
             ui.warn(_('warning: error finding commands in %s\n') % path)
             ui.traceback()
             return
         for c in aliases:
             if c.startswith(cmd):
                 cmd = c
                 break
         else:
             cmd = aliases[0]
         return (cmd, name, mod)
 
     ext = None
     # first, search for an extension with the same name as the command
     path = paths.pop(cmd, None)
     if path:
         ext = findcmd(cmd, cmd, path)
     if not ext:
         # otherwise, interrogate each extension until there's a match
         for name, path in paths.iteritems():
             ext = findcmd(cmd, name, path)
             if ext:
                 break
     if ext and 'DEPRECATED' not in ext.__doc__:
         return ext
 
     raise error.UnknownCommand(cmd)
 
 def enabled(shortname=True):
     '''return a dict of {name: desc} of extensions'''
     exts = {}
     for ename, ext in extensions():
         doc = (gettext(ext.__doc__) or _('(no help text available)'))
         if shortname:
             ename = ename.split('.')[-1]
         exts[ename] = doc.splitlines()[0].strip()
 
     return exts
 
 def notloaded():
     '''return short names of extensions that failed to load'''
     return [name for name, mod in _extensions.iteritems() if mod is None]
 
 def moduleversion(module):
     '''return version information from given module as a string'''
     if (util.safehasattr(module, 'getversion')
           and callable(module.getversion)):
         version = module.getversion()
     elif util.safehasattr(module, '__version__'):
         version = module.__version__
     else:
         version = ''
     if isinstance(version, (list, tuple)):
         version = '.'.join(str(o) for o in version)
     return version
 
 def ismoduleinternal(module):
     exttestedwith = getattr(module, 'testedwith', None)
     return exttestedwith == "ships-with-hg-core"

tests/test-extension.t

@@ -1,1633 +1,1659 b''
 Test basic extension support
 
   $ cat > foobar.py <<EOF
   > import os
   > from mercurial import commands, registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > def uisetup(ui):
   >     ui.write("uisetup called\\n")
   >     ui.flush()
   > def reposetup(ui, repo):
   >     ui.write("reposetup called for %s\\n" % os.path.basename(repo.root))
   >     ui.write("ui %s= repo.ui\\n" % (ui == repo.ui and "=" or "!"))
   >     ui.flush()
   > @command('foo', [], 'hg foo')
   > def foo(ui, *args, **kwargs):
   >     ui.write("Foo\\n")
   > @command('bar', [], 'hg bar', norepo=True)
   > def bar(ui, *args, **kwargs):
   >     ui.write("Bar\\n")
   > EOF
   $ abspath=`pwd`/foobar.py
 
   $ mkdir barfoo
   $ cp foobar.py barfoo/__init__.py
   $ barfoopath=`pwd`/barfoo
 
   $ hg init a
   $ cd a
   $ echo foo > file
   $ hg add file
   $ hg commit -m 'add file'
 
   $ echo '[extensions]' >> $HGRCPATH
   $ echo "foobar = $abspath" >> $HGRCPATH
   $ hg foo
   uisetup called
   reposetup called for a
   ui == repo.ui
   Foo
 
   $ cd ..
   $ hg clone a b
   uisetup called
   reposetup called for a
   ui == repo.ui
   reposetup called for b
   ui == repo.ui
   updating to branch default
   1 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
   $ hg bar
   uisetup called
   Bar
   $ echo 'foobar = !' >> $HGRCPATH
 
 module/__init__.py-style
 
   $ echo "barfoo = $barfoopath" >> $HGRCPATH
   $ cd a
   $ hg foo
   uisetup called
   reposetup called for a
   ui == repo.ui
   Foo
   $ echo 'barfoo = !' >> $HGRCPATH
 
 Check that extensions are loaded in phases:
 
   $ cat > foo.py <<EOF
   > import os
   > name = os.path.basename(__file__).rsplit('.', 1)[0]
   > print "1) %s imported" % name
   > def uisetup(ui):
   >     print "2) %s uisetup" % name
   > def extsetup():
   >     print "3) %s extsetup" % name
   > def reposetup(ui, repo):
   >    print "4) %s reposetup" % name
   > EOF
 
   $ cp foo.py bar.py
   $ echo 'foo = foo.py' >> $HGRCPATH
   $ echo 'bar = bar.py' >> $HGRCPATH
 
 Command with no output, we just want to see the extensions loaded:
 
   $ hg paths
   1) foo imported
   1) bar imported
   2) foo uisetup
   2) bar uisetup
   3) foo extsetup
   3) bar extsetup
   4) foo reposetup
   4) bar reposetup
 
 Check hgweb's load order:
 
   $ cat > hgweb.cgi <<EOF
   > #!/usr/bin/env python
   > from mercurial import demandimport; demandimport.enable()
   > from mercurial.hgweb import hgweb
   > from mercurial.hgweb import wsgicgi
   > application = hgweb('.', 'test repo')
   > wsgicgi.launch(application)
   > EOF
 
   $ REQUEST_METHOD='GET' PATH_INFO='/' SCRIPT_NAME='' QUERY_STRING='' \
   >    SERVER_PORT='80' SERVER_NAME='localhost' python hgweb.cgi \
   >    | grep '^[0-9]) ' # ignores HTML output
   1) foo imported
   1) bar imported
   2) foo uisetup
   2) bar uisetup
   3) foo extsetup
   3) bar extsetup
   4) foo reposetup
   4) bar reposetup
 
   $ echo 'foo = !' >> $HGRCPATH
   $ echo 'bar = !' >> $HGRCPATH
 
 Check "from __future__ import absolute_import" support for external libraries
 
 #if windows
   $ PATHSEP=";"
 #else
   $ PATHSEP=":"
 #endif
   $ export PATHSEP
 
   $ mkdir $TESTTMP/libroot
   $ echo "s = 'libroot/ambig.py'" > $TESTTMP/libroot/ambig.py
   $ mkdir $TESTTMP/libroot/mod
   $ touch $TESTTMP/libroot/mod/__init__.py
   $ echo "s = 'libroot/mod/ambig.py'" > $TESTTMP/libroot/mod/ambig.py
 
 #if absimport
   $ cat > $TESTTMP/libroot/mod/ambigabs.py <<EOF
   > from __future__ import absolute_import
   > import ambig # should load "libroot/ambig.py"
   > s = ambig.s
   > EOF
   $ cat > loadabs.py <<EOF
   > import mod.ambigabs as ambigabs
   > def extsetup():
   >     print 'ambigabs.s=%s' % ambigabs.s
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}/libroot; hg --config extensions.loadabs=loadabs.py root)
   ambigabs.s=libroot/ambig.py
   $TESTTMP/a (glob)
 #endif
 
 #if no-py3k
   $ cat > $TESTTMP/libroot/mod/ambigrel.py <<EOF
   > import ambig # should load "libroot/mod/ambig.py"
   > s = ambig.s
   > EOF
   $ cat > loadrel.py <<EOF
   > import mod.ambigrel as ambigrel
   > def extsetup():
   >     print 'ambigrel.s=%s' % ambigrel.s
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}/libroot; hg --config extensions.loadrel=loadrel.py root)
   ambigrel.s=libroot/mod/ambig.py
   $TESTTMP/a (glob)
 #endif
 
 Check absolute/relative import of extension specific modules
 
   $ mkdir $TESTTMP/extroot
   $ cat > $TESTTMP/extroot/bar.py <<EOF
   > s = 'this is extroot.bar'
   > EOF
   $ mkdir $TESTTMP/extroot/sub1
   $ cat > $TESTTMP/extroot/sub1/__init__.py <<EOF
   > s = 'this is extroot.sub1.__init__'
   > EOF
   $ cat > $TESTTMP/extroot/sub1/baz.py <<EOF
   > s = 'this is extroot.sub1.baz'
   > EOF
   $ cat > $TESTTMP/extroot/__init__.py <<EOF
   > s = 'this is extroot.__init__'
   > import foo
   > def extsetup(ui):
   >     ui.write('(extroot) ', foo.func(), '\n')
   >     ui.flush()
   > EOF
 
   $ cat > $TESTTMP/extroot/foo.py <<EOF
   > # test absolute import
   > buf = []
   > def func():
   >     # "not locals" case
   >     import extroot.bar
   >     buf.append('import extroot.bar in func(): %s' % extroot.bar.s)
   >     return '\n(extroot) '.join(buf)
   > # "fromlist == ('*',)" case
   > from extroot.bar import *
   > buf.append('from extroot.bar import *: %s' % s)
   > # "not fromlist" and "if '.' in name" case
   > import extroot.sub1.baz
   > buf.append('import extroot.sub1.baz: %s' % extroot.sub1.baz.s)
   > # "not fromlist" and NOT "if '.' in name" case
   > import extroot
   > buf.append('import extroot: %s' % extroot.s)
   > # NOT "not fromlist" and NOT "level != -1" case
   > from extroot.bar import s
   > buf.append('from extroot.bar import s: %s' % s)
   > EOF
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.extroot=$TESTTMP/extroot root)
   (extroot) from extroot.bar import *: this is extroot.bar
   (extroot) import extroot.sub1.baz: this is extroot.sub1.baz
   (extroot) import extroot: this is extroot.__init__
   (extroot) from extroot.bar import s: this is extroot.bar
   (extroot) import extroot.bar in func(): this is extroot.bar
   $TESTTMP/a (glob)
 
 #if no-py3k
   $ rm "$TESTTMP"/extroot/foo.*
   $ cat > $TESTTMP/extroot/foo.py <<EOF
   > # test relative import
   > buf = []
   > def func():
   >     # "not locals" case
   >     import bar
   >     buf.append('import bar in func(): %s' % bar.s)
   >     return '\n(extroot) '.join(buf)
   > # "fromlist == ('*',)" case
   > from bar import *
   > buf.append('from bar import *: %s' % s)
   > # "not fromlist" and "if '.' in name" case
   > import sub1.baz
   > buf.append('import sub1.baz: %s' % sub1.baz.s)
   > # "not fromlist" and NOT "if '.' in name" case
   > import sub1
   > buf.append('import sub1: %s' % sub1.s)
   > # NOT "not fromlist" and NOT "level != -1" case
   > from bar import s
   > buf.append('from bar import s: %s' % s)
   > EOF
   $ hg --config extensions.extroot=$TESTTMP/extroot root
   (extroot) from bar import *: this is extroot.bar
   (extroot) import sub1.baz: this is extroot.sub1.baz
   (extroot) import sub1: this is extroot.sub1.__init__
   (extroot) from bar import s: this is extroot.bar
   (extroot) import bar in func(): this is extroot.bar
   $TESTTMP/a (glob)
 #endif
 
 #if demandimport absimport
 
 Examine whether module loading is delayed until actual referring, even
 though module is imported with "absolute_import" feature.
 
 Files below in each packages are used for described purpose:
 
 - "called": examine whether "from MODULE import ATTR" works correctly
 - "unused": examine whether loading is delayed correctly
 - "used":   examine whether "from PACKAGE import MODULE" works correctly
 
 Package hierarchy is needed to examine whether demand importing works
 as expected for "from SUB.PACK.AGE import MODULE".
 
 Setup "external library" to be imported with "absolute_import"
 feature.
 
   $ mkdir -p $TESTTMP/extlibroot/lsub1/lsub2
   $ touch $TESTTMP/extlibroot/__init__.py
   $ touch $TESTTMP/extlibroot/lsub1/__init__.py
   $ touch $TESTTMP/extlibroot/lsub1/lsub2/__init__.py
 
   $ cat > $TESTTMP/extlibroot/lsub1/lsub2/called.py <<EOF
   > def func():
   >     return "this is extlibroot.lsub1.lsub2.called.func()"
   > EOF
   $ cat > $TESTTMP/extlibroot/lsub1/lsub2/unused.py <<EOF
   > raise Exception("extlibroot.lsub1.lsub2.unused is loaded unintentionally")
   > EOF
   $ cat > $TESTTMP/extlibroot/lsub1/lsub2/used.py <<EOF
   > detail = "this is extlibroot.lsub1.lsub2.used"
   > EOF
 
 Setup sub-package of "external library", which causes instantiation of
 demandmod in "recurse down the module chain" code path. Relative
 importing with "absolute_import" feature isn't tested, because "level
 >=1 " doesn't cause instantiation of demandmod.
 
   $ mkdir -p $TESTTMP/extlibroot/recursedown/abs
   $ cat > $TESTTMP/extlibroot/recursedown/abs/used.py <<EOF
   > detail = "this is extlibroot.recursedown.abs.used"
   > EOF
   $ cat > $TESTTMP/extlibroot/recursedown/abs/__init__.py <<EOF
   > from __future__ import absolute_import
   > from extlibroot.recursedown.abs.used import detail
   > EOF
 
   $ mkdir -p $TESTTMP/extlibroot/recursedown/legacy
   $ cat > $TESTTMP/extlibroot/recursedown/legacy/used.py <<EOF
   > detail = "this is extlibroot.recursedown.legacy.used"
   > EOF
   $ cat > $TESTTMP/extlibroot/recursedown/legacy/__init__.py <<EOF
   > # legacy style (level == -1) import
   > from extlibroot.recursedown.legacy.used import detail
   > EOF
 
   $ cat > $TESTTMP/extlibroot/recursedown/__init__.py <<EOF
   > from __future__ import absolute_import
   > from extlibroot.recursedown.abs import detail as absdetail
   > from .legacy import detail as legacydetail
   > EOF
 
 Setup extension local modules to be imported with "absolute_import"
 feature.
 
   $ mkdir -p $TESTTMP/absextroot/xsub1/xsub2
   $ touch $TESTTMP/absextroot/xsub1/__init__.py
   $ touch $TESTTMP/absextroot/xsub1/xsub2/__init__.py
 
   $ cat > $TESTTMP/absextroot/xsub1/xsub2/called.py <<EOF
   > def func():
   >     return "this is absextroot.xsub1.xsub2.called.func()"
   > EOF
   $ cat > $TESTTMP/absextroot/xsub1/xsub2/unused.py <<EOF
   > raise Exception("absextroot.xsub1.xsub2.unused is loaded unintentionally")
   > EOF
   $ cat > $TESTTMP/absextroot/xsub1/xsub2/used.py <<EOF
   > detail = "this is absextroot.xsub1.xsub2.used"
   > EOF
 
 Setup extension local modules to examine whether demand importing
 works as expected in "level > 1" case.
 
   $ cat > $TESTTMP/absextroot/relimportee.py <<EOF
   > detail = "this is absextroot.relimportee"
   > EOF
   $ cat > $TESTTMP/absextroot/xsub1/xsub2/relimporter.py <<EOF
   > from __future__ import absolute_import
   > from ... import relimportee
   > detail = "this relimporter imports %r" % (relimportee.detail)
   > EOF
 
 Setup modules, which actually import extension local modules at
 runtime.
 
   $ cat > $TESTTMP/absextroot/absolute.py << EOF
   > from __future__ import absolute_import
   > 
   > # import extension local modules absolutely (level = 0)
   > from absextroot.xsub1.xsub2 import used, unused
   > from absextroot.xsub1.xsub2.called import func
   > 
   > def getresult():
   >     result = []
   >     result.append(used.detail)
   >     result.append(func())
   >     return result
   > EOF
 
   $ cat > $TESTTMP/absextroot/relative.py << EOF
   > from __future__ import absolute_import
   > 
   > # import extension local modules relatively (level == 1)
   > from .xsub1.xsub2 import used, unused
   > from .xsub1.xsub2.called import func
   > 
   > # import a module, which implies "importing with level > 1"
   > from .xsub1.xsub2 import relimporter
   > 
   > def getresult():
   >     result = []
   >     result.append(used.detail)
   >     result.append(func())
   >     result.append(relimporter.detail)
   >     return result
   > EOF
 
 Setup main procedure of extension.
 
   $ cat > $TESTTMP/absextroot/__init__.py <<EOF
   > from __future__ import absolute_import
   > from mercurial import registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > 
   > # "absolute" and "relative" shouldn't be imported before actual
   > # command execution, because (1) they import same modules, and (2)
   > # preceding import (= instantiate "demandmod" object instead of
   > # real "module" object) might hide problem of succeeding import.
   > 
   > @command('showabsolute', [], norepo=True)
   > def showabsolute(ui, *args, **opts):
   >     from absextroot import absolute
   >     ui.write('ABS: %s\n' % '\nABS: '.join(absolute.getresult()))
   > 
   > @command('showrelative', [], norepo=True)
   > def showrelative(ui, *args, **opts):
   >     from . import relative
   >     ui.write('REL: %s\n' % '\nREL: '.join(relative.getresult()))
   > 
   > # import modules from external library
   > from extlibroot.lsub1.lsub2 import used as lused, unused as lunused
   > from extlibroot.lsub1.lsub2.called import func as lfunc
   > from extlibroot.recursedown import absdetail, legacydetail
   > 
   > def uisetup(ui):
   >     result = []
   >     result.append(lused.detail)
   >     result.append(lfunc())
   >     result.append(absdetail)
   >     result.append(legacydetail)
   >     ui.write('LIB: %s\n' % '\nLIB: '.join(result))
   > EOF
 
 Examine module importing.
 
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.absextroot=$TESTTMP/absextroot showabsolute)
   LIB: this is extlibroot.lsub1.lsub2.used
   LIB: this is extlibroot.lsub1.lsub2.called.func()
   LIB: this is extlibroot.recursedown.abs.used
   LIB: this is extlibroot.recursedown.legacy.used
   ABS: this is absextroot.xsub1.xsub2.used
   ABS: this is absextroot.xsub1.xsub2.called.func()
 
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.absextroot=$TESTTMP/absextroot showrelative)
   LIB: this is extlibroot.lsub1.lsub2.used
   LIB: this is extlibroot.lsub1.lsub2.called.func()
   LIB: this is extlibroot.recursedown.abs.used
   LIB: this is extlibroot.recursedown.legacy.used
   REL: this is absextroot.xsub1.xsub2.used
   REL: this is absextroot.xsub1.xsub2.called.func()
   REL: this relimporter imports 'this is absextroot.relimportee'
 
 Examine whether sub-module is imported relatively as expected.
 
 See also issue5208 for detail about example case on Python 3.x.
 
   $ f -q $TESTTMP/extlibroot/lsub1/lsub2/notexist.py
   $TESTTMP/extlibroot/lsub1/lsub2/notexist.py: file not found
 
   $ cat > $TESTTMP/notexist.py <<EOF
   > text = 'notexist.py at root is loaded unintentionally\n'
   > EOF
 
   $ cat > $TESTTMP/checkrelativity.py <<EOF
   > from mercurial import registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > 
   > # demand import avoids failure of importing notexist here
   > import extlibroot.lsub1.lsub2.notexist
   > 
   > @command('checkrelativity', [], norepo=True)
   > def checkrelativity(ui, *args, **opts):
   >     try:
   >         ui.write(extlibroot.lsub1.lsub2.notexist.text)
   >         return 1 # unintentional success
   >     except ImportError:
   >         pass # intentional failure
   > EOF
 
   $ (PYTHONPATH=${PYTHONPATH}${PATHSEP}${TESTTMP}; hg --config extensions.checkrelativity=$TESTTMP/checkrelativity.py checkrelativity)
 
 #endif
 
   $ cd ..
 
 hide outer repo
   $ hg init
 
   $ cat > empty.py <<EOF
   > '''empty cmdtable
   > '''
   > cmdtable = {}
   > EOF
   $ emptypath=`pwd`/empty.py
   $ echo "empty = $emptypath" >> $HGRCPATH
   $ hg help empty
   empty extension - empty cmdtable
   
   no commands defined
 
 
   $ echo 'empty = !' >> $HGRCPATH
 
   $ cat > debugextension.py <<EOF
   > '''only debugcommands
   > '''
   > from mercurial import registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command('debugfoobar', [], 'hg debugfoobar')
   > def debugfoobar(ui, repo, *args, **opts):
   >     "yet another debug command"
   >     pass
   > @command('foo', [], 'hg foo')
   > def foo(ui, repo, *args, **opts):
   >     """yet another foo command
   >     This command has been DEPRECATED since forever.
   >     """
   >     pass
   > EOF
   $ debugpath=`pwd`/debugextension.py
   $ echo "debugextension = $debugpath" >> $HGRCPATH
 
   $ hg help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
   (some details hidden, use --verbose to show complete help)
 
 
   $ hg --verbose help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
    -T --template TEMPLATE display with template (EXPERIMENTAL)
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
 
 
 
 
 
   $ hg --debug help debugextension
   hg debugextensions
   
   show information about active extensions
   
   options:
   
    -T --template TEMPLATE display with template (EXPERIMENTAL)
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
 
 
 
 
   $ echo 'debugextension = !' >> $HGRCPATH
 
 Asking for help about a deprecated extension should do something useful:
 
   $ hg help glog
   'glog' is provided by the following extension:
   
       graphlog      command to view revision graphs from a shell (DEPRECATED)
   
   (use 'hg help extensions' for information on enabling extensions)
 
 Extension module help vs command help:
 
   $ echo 'extdiff =' >> $HGRCPATH
   $ hg help extdiff
   hg extdiff [OPT]... [FILE]...
   
   use external program to diff repository (or selected files)
   
       Show differences between revisions for the specified files, using an
       external program. The default program used is diff, with default options
       "-Npru".
   
       To select a different program, use the -p/--program option. The program
       will be passed the names of two directories to compare. To pass additional
       options to the program, use -o/--option. These will be passed before the
       names of the directories to compare.
   
       When two revision arguments are given, then changes are shown between
       those revisions. If only one revision is specified then that revision is
       compared to the working directory, and, when no revisions are specified,
       the working directory files are compared to its parent.
   
   (use 'hg help -e extdiff' to show help for the extdiff extension)
   
   options ([+] can be repeated):
   
    -p --program CMD         comparison program to run
    -o --option OPT [+]      pass option to comparison program
    -r --rev REV [+]         revision
    -c --change REV          change made by revision
       --patch               compare patches for two revisions
    -I --include PATTERN [+] include names matching the given patterns
    -X --exclude PATTERN [+] exclude names matching the given patterns
    -S --subrepos            recurse into subrepositories
   
   (some details hidden, use --verbose to show complete help)
 
 
 
 
 
 
 
 
 
 
   $ hg help --extension extdiff
   extdiff extension - command to allow external programs to compare revisions
   
   The extdiff Mercurial extension allows you to use external programs to compare
   revisions, or revision with working directory. The external diff programs are
   called with a configurable set of options and two non-option arguments: paths
   to directories containing snapshots of files to compare.
   
   The extdiff extension also allows you to configure new diff commands, so you
   do not need to type 'hg extdiff -p kdiff3' always.
   
     [extdiff]
     # add new command that runs GNU diff(1) in 'context diff' mode
     cdiff = gdiff -Nprc5
     ## or the old way:
     #cmd.cdiff = gdiff
     #opts.cdiff = -Nprc5
   
     # add new command called meld, runs meld (no need to name twice).  If
     # the meld executable is not available, the meld tool in [merge-tools]
     # will be used, if available
     meld =
   
     # add new command called vimdiff, runs gvimdiff with DirDiff plugin
     # (see http://www.vim.org/scripts/script.php?script_id=102) Non
     # English user, be sure to put "let g:DirDiffDynamicDiffText = 1" in
     # your .vimrc
     vimdiff = gvim -f "+next" \
               "+execute 'DirDiff' fnameescape(argv(0)) fnameescape(argv(1))"
   
   Tool arguments can include variables that are expanded at runtime:
   
     $parent1, $plabel1 - filename, descriptive label of first parent
     $child,   $clabel  - filename, descriptive label of child revision
     $parent2, $plabel2 - filename, descriptive label of second parent
     $root              - repository root
     $parent is an alias for $parent1.
   
   The extdiff extension will look in your [diff-tools] and [merge-tools]
   sections for diff tool arguments, when none are specified in [extdiff].
   
     [extdiff]
     kdiff3 =
   
     [diff-tools]
     kdiff3.diffargs=--L1 '$plabel1' --L2 '$clabel' $parent $child
   
   You can use -I/-X and list of file or directory names like normal 'hg diff'
   command. The extdiff extension makes snapshots of only needed files, so
   running the external diff program will actually be pretty fast (at least
   faster than having to compare the entire tree).
   
   list of commands:
   
    extdiff       use external program to diff repository (or selected files)
   
   (use 'hg help -v -e extdiff' to show built-in aliases and global options)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   $ echo 'extdiff = !' >> $HGRCPATH
 
 Test help topic with same name as extension
 
   $ cat > multirevs.py <<EOF
   > from mercurial import commands, registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > """multirevs extension
   > Big multi-line module docstring."""
   > @command('multirevs', [], 'ARG', norepo=True)
   > def multirevs(ui, repo, arg, *args, **opts):
   >     """multirevs command"""
   >     pass
   > EOF
   $ echo "multirevs = multirevs.py" >> $HGRCPATH
 
   $ hg help multirevs | tail
         bookmark (this works because the last revision of the revset is used):
   
           hg update :@
   
       - Show diff between tags 1.3 and 1.5 (this works because the first and the
         last revisions of the revset are used):
   
           hg diff -r 1.3::1.5
   
   use 'hg help -c multirevs' to see help for the multirevs command
 
 
 
 
 
 
   $ hg help -c multirevs
   hg multirevs ARG
   
   multirevs command
   
   (some details hidden, use --verbose to show complete help)
 
 
 
   $ hg multirevs
   hg multirevs: invalid arguments
   hg multirevs ARG
   
   multirevs command
   
   (use 'hg multirevs -h' to show more help)
   [255]
 
 
 
   $ echo "multirevs = !" >> $HGRCPATH
 
 Issue811: Problem loading extensions twice (by site and by user)
 
   $ cat <<EOF >> $HGRCPATH
   > mq =
   > strip =
   > hgext.mq =
   > hgext/mq =
   > EOF
 
 Show extensions:
 (note that mq force load strip, also checking it's not loaded twice)
 
   $ hg debugextensions
   mq
   strip
 
 For extensions, which name matches one of its commands, help
 message should ask '-v -e' to get list of built-in aliases
 along with extension help itself
 
   $ mkdir $TESTTMP/d
   $ cat > $TESTTMP/d/dodo.py <<EOF
   > """
   > This is an awesome 'dodo' extension. It does nothing and
   > writes 'Foo foo'
   > """
   > from mercurial import commands, registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command('dodo', [], 'hg dodo')
   > def dodo(ui, *args, **kwargs):
   >     """Does nothing"""
   >     ui.write("I do nothing. Yay\\n")
   > @command('foofoo', [], 'hg foofoo')
   > def foofoo(ui, *args, **kwargs):
   >     """Writes 'Foo foo'"""
   >     ui.write("Foo foo\\n")
   > EOF
   $ dodopath=$TESTTMP/d/dodo.py
 
   $ echo "dodo = $dodopath" >> $HGRCPATH
 
 Make sure that user is asked to enter '-v -e' to get list of built-in aliases
   $ hg help -e dodo
   dodo extension -
   
   This is an awesome 'dodo' extension. It does nothing and writes 'Foo foo'
   
   list of commands:
   
    dodo          Does nothing
    foofoo        Writes 'Foo foo'
   
   (use 'hg help -v -e dodo' to show built-in aliases and global options)
 
 Make sure that '-v -e' prints list of built-in aliases along with
 extension help itself
   $ hg help -v -e dodo
   dodo extension -
   
   This is an awesome 'dodo' extension. It does nothing and writes 'Foo foo'
   
   list of commands:
   
    dodo          Does nothing
    foofoo        Writes 'Foo foo'
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
 Make sure that single '-v' option shows help and built-ins only for 'dodo' command
   $ hg help -v dodo
   hg dodo
   
   Does nothing
   
   (use 'hg help -e dodo' to show help for the dodo extension)
   
   options:
   
     --mq operate on patch repository
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
 In case when extension name doesn't match any of its commands,
 help message should ask for '-v' to get list of built-in aliases
 along with extension help
   $ cat > $TESTTMP/d/dudu.py <<EOF
   > """
   > This is an awesome 'dudu' extension. It does something and
   > also writes 'Beep beep'
   > """
   > from mercurial import commands, registrar
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > @command('something', [], 'hg something')
   > def something(ui, *args, **kwargs):
   >     """Does something"""
   >     ui.write("I do something. Yaaay\\n")
   > @command('beep', [], 'hg beep')
   > def beep(ui, *args, **kwargs):
   >     """Writes 'Beep beep'"""
   >     ui.write("Beep beep\\n")
   > EOF
   $ dudupath=$TESTTMP/d/dudu.py
 
   $ echo "dudu = $dudupath" >> $HGRCPATH
 
   $ hg help -e dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   (use 'hg help -v dudu' to show built-in aliases and global options)
 
 In case when extension name doesn't match any of its commands,
 help options '-v' and '-v -e' should be equivalent
   $ hg help -v dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
   $ hg help -v -e dudu
   dudu extension -
   
   This is an awesome 'dudu' extension. It does something and also writes 'Beep
   beep'
   
   list of commands:
   
    beep          Writes 'Beep beep'
    something     Does something
   
   global options ([+] can be repeated):
   
    -R --repository REPO   repository root directory or name of overlay bundle
                           file
       --cwd DIR           change working directory
    -y --noninteractive    do not prompt, automatically pick the first choice for
                           all prompts
    -q --quiet             suppress output
    -v --verbose           enable additional output
       --color TYPE        when to colorize (boolean, always, auto, never, or
                           debug)
       --config CONFIG [+] set/override config option (use 'section.name=value')
       --debug             enable debugging output
       --debugger          start debugger
       --encoding ENCODE   set the charset encoding (default: ascii)
       --encodingmode MODE set the charset encoding mode (default: strict)
       --traceback         always print a traceback on exception
       --time              time how long the command takes
       --profile           print command execution profile
       --version           output version information and exit
    -h --help              display help and exit
       --hidden            consider hidden changesets
       --pager TYPE        when to paginate (boolean, always, auto, or never)
                           (default: auto)
 
 Disabled extension commands:
 
   $ ORGHGRCPATH=$HGRCPATH
   $ HGRCPATH=
   $ export HGRCPATH
   $ hg help email
   'email' is provided by the following extension:
   
       patchbomb     command to send changesets as (a series of) patch emails
   
   (use 'hg help extensions' for information on enabling extensions)
 
 
   $ hg qdel
   hg: unknown command 'qdel'
   'qdelete' is provided by the following extension:
   
       mq            manage a stack of patches
   
   (use 'hg help extensions' for information on enabling extensions)
   [255]
 
 
   $ hg churn
   hg: unknown command 'churn'
   'churn' is provided by the following extension:
   
       churn         command to display statistics about repository history
   
   (use 'hg help extensions' for information on enabling extensions)
   [255]
 
 
 
 Disabled extensions:
 
   $ hg help churn
   churn extension - command to display statistics about repository history
   
   (use 'hg help extensions' for information on enabling extensions)
 
   $ hg help patchbomb
   patchbomb extension - command to send changesets as (a series of) patch emails
   
   The series is started off with a "[PATCH 0 of N]" introduction, which
   describes the series as a whole.
   
   Each patch email has a Subject line of "[PATCH M of N] ...", using the first
   line of the changeset description as the subject text. The message contains
   two or three body parts:
   
   - The changeset description.
   - [Optional] The result of running diffstat on the patch.
   - The patch itself, as generated by 'hg export'.
   
   Each message refers to the first in the series using the In-Reply-To and
   References headers, so they will show up as a sequence in threaded mail and
   news readers, and in mail archives.
   
   To configure other defaults, add a section like this to your configuration
   file:
   
     [email]
     from = My Name <my@email>
     to = recipient1, recipient2, ...
     cc = cc1, cc2, ...
     bcc = bcc1, bcc2, ...
     reply-to = address1, address2, ...
   
   Use "[patchbomb]" as configuration section name if you need to override global
   "[email]" address settings.
   
   Then you can use the 'hg email' command to mail a series of changesets as a
   patchbomb.
   
   You can also either configure the method option in the email section to be a
   sendmail compatible mailer or fill out the [smtp] section so that the
   patchbomb extension can automatically send patchbombs directly from the
   commandline. See the [email] and [smtp] sections in hgrc(5) for details.
   
   By default, 'hg email' will prompt for a "To" or "CC" header if you do not
   supply one via configuration or the command line.  You can override this to
   never prompt by configuring an empty value:
   
     [email]
     cc =
   
   You can control the default inclusion of an introduction message with the
   "patchbomb.intro" configuration option. The configuration is always
   overwritten by command line flags like --intro and --desc:
   
     [patchbomb]
     intro=auto   # include introduction message if more than 1 patch (default)
     intro=never  # never include an introduction message
     intro=always # always include an introduction message
   
   You can specify a template for flags to be added in subject prefixes. Flags
   specified by --flag option are exported as "{flags}" keyword:
   
     [patchbomb]
     flagtemplate = "{separate(' ',
                               ifeq(branch, 'default', '', branch|upper),
                               flags)}"
   
   You can set patchbomb to always ask for confirmation by setting
   "patchbomb.confirm" to true.
   
   (use 'hg help extensions' for information on enabling extensions)
 
 
 Broken disabled extension and command:
 
   $ mkdir hgext
   $ echo > hgext/__init__.py
   $ cat > hgext/broken.py <<EOF
   > "broken extension'
   > EOF
   $ cat > path.py <<EOF
   > import os, sys
   > sys.path.insert(0, os.environ['HGEXTPATH'])
   > EOF
   $ HGEXTPATH=`pwd`
   $ export HGEXTPATH
 
   $ hg --config extensions.path=./path.py help broken
   broken extension - (no help text available)
   
   (use 'hg help extensions' for information on enabling extensions)
 
 
   $ cat > hgext/forest.py <<EOF
   > cmdtable = None
   > EOF
   $ hg --config extensions.path=./path.py help foo > /dev/null
   warning: error finding commands in $TESTTMP/hgext/forest.py (glob)
   abort: no such help topic: foo
   (try 'hg help --keyword foo')
   [255]
 
   $ cat > throw.py <<EOF
   > from mercurial import commands, registrar, util
   > cmdtable = {}
   > command = registrar.command(cmdtable)
   > class Bogon(Exception): pass
   > @command('throw', [], 'hg throw', norepo=True)
   > def throw(ui, **opts):
   >     """throws an exception"""
   >     raise Bogon()
   > EOF
 
 No declared supported version, extension complains:
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM * (glob)
   ** Extensions loaded: throw
 
 empty declaration of supported version, extension complains:
   $ echo "testedwith = ''" >> throw.py
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 If the extension specifies a buglink, show that:
   $ echo 'buglink = "http://example.com/bts"' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions unknown of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to http://example.com/bts
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 If the extensions declare outdated versions, accuse the older extension first:
   $ echo "from mercurial import util" >> older.py
   $ echo "util.version = lambda:'2.2'" >> older.py
   $ echo "testedwith = '1.9.3'" >> older.py
   $ echo "testedwith = '2.1.1'" >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
   ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 2.2)
   ** Extensions loaded: throw, older
 
 One extension only tested with older, one only with newer versions:
   $ echo "util.version = lambda:'2.1'" >> older.py
   $ rm -f older.pyc older.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension older
   ** which supports versions 1.9 of Mercurial.
   ** Please disable older and try your action again.
   ** If that fixes the bug please report it to the extension author.
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 2.1)
   ** Extensions loaded: throw, older
 
 Older extension is tested with current version, the other only with newer:
   $ echo "util.version = lambda:'1.9.3'" >> older.py
   $ rm -f older.pyc older.pyo
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   throw 2>&1 | egrep '^\*\*'
   ** Unknown exception encountered with possibly-broken third-party extension throw
   ** which supports versions 2.1 of Mercurial.
   ** Please disable throw and try your action again.
   ** If that fixes the bug please report it to http://example.com/bts
   ** Python * (glob)
   ** Mercurial Distributed SCM (version 1.9.3)
   ** Extensions loaded: throw, older
 
 Ability to point to a different point
   $ hg --config extensions.throw=throw.py --config extensions.older=older.py \
   >   --config ui.supportcontact='Your Local Goat Lenders' throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** Your Local Goat Lenders
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw, older
 
 Declare the version as supporting this hg version, show regular bts link:
   $ hgver=`hg debuginstall -T '{hgver}'`
   $ echo 'testedwith = """'"$hgver"'"""' >> throw.py
   $ if [ -z "$hgver" ]; then
   >   echo "unable to fetch a mercurial version. Make sure __version__ is correct";
   > fi
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** https://mercurial-scm.org/wiki/BugTracker
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 Patch version is ignored during compatibility check
   $ echo "testedwith = '3.2'" >> throw.py
   $ echo "util.version = lambda:'3.2.2'" >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg --config extensions.throw=throw.py throw 2>&1 | egrep '^\*\*'
   ** unknown exception encountered, please report by visiting
   ** https://mercurial-scm.org/wiki/BugTracker
   ** Python * (glob)
   ** Mercurial Distributed SCM (*) (glob)
   ** Extensions loaded: throw
 
 Test version number support in 'hg version':
   $ echo '__version__ = (1, 2, 3)' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg version -v
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
 
   $ hg version -v --config extensions.throw=throw.py
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
     throw  external  1.2.3
   $ echo 'getversion = lambda: "1.twentythree"' >> throw.py
   $ rm -f throw.pyc throw.pyo
   $ hg version -v --config extensions.throw=throw.py --config extensions.strip=
   Mercurial Distributed SCM (version *) (glob)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   
   Enabled extensions:
   
     throw  external  1.twentythree
     strip  internal  
 
   $ hg version -q --config extensions.throw=throw.py
   Mercurial Distributed SCM (version *) (glob)
 
 Test JSON output of version:
 
   $ hg version -Tjson
   [
    {
     "extensions": [],
     "ver": "*" (glob)
    }
   ]
 
   $ hg version --config extensions.throw=throw.py -Tjson
   [
    {
     "extensions": [{"bundled": false, "name": "throw", "ver": "1.twentythree"}],
     "ver": "3.2.2"
    }
   ]
 
   $ hg version --config extensions.strip= -Tjson
   [
    {
     "extensions": [{"bundled": true, "name": "strip", "ver": null}],
     "ver": "*" (glob)
    }
   ]
 
 Test template output of version:
 
   $ hg version --config extensions.throw=throw.py --config extensions.strip= \
   > -T'{extensions % "{name}  {pad(ver, 16)}  ({if(bundled, "internal", "external")})\n"}'
   throw  1.twentythree     (external)
   strip                    (internal)
 
 Refuse to load extensions with minimum version requirements
 
   $ cat > minversion1.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.5.2'
   > minimumhgversion = '3.6'
   > EOF
   $ hg --config extensions.minversion=minversion1.py version
   (third party extension minversion requires version 3.6 or newer of Mercurial; disabling)
   Mercurial Distributed SCM (version 3.5.2)
   (see https://mercurial-scm.org for more information)
   
   Copyright (C) 2005-* Matt Mackall and others (glob)
   This is free software; see the source for copying conditions. There is NO
   warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 
   $ cat > minversion2.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.6'
   > minimumhgversion = '3.7'
   > EOF
   $ hg --config extensions.minversion=minversion2.py version 2>&1 | egrep '\(third'
   (third party extension minversion requires version 3.7 or newer of Mercurial; disabling)
 
 Can load version that is only off by point release
 
   $ cat > minversion2.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.6.1'
   > minimumhgversion = '3.6'
   > EOF
   $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
   [1]
 
 Can load minimum version identical to current
 
   $ cat > minversion3.py << EOF
   > from mercurial import util
   > util.version = lambda: '3.5'
   > minimumhgversion = '3.5'
   > EOF
   $ hg --config extensions.minversion=minversion3.py version 2>&1 | egrep '\(third'
   [1]
 
 Restore HGRCPATH
 
   $ HGRCPATH=$ORGHGRCPATH
   $ export HGRCPATH
 
 Commands handling multiple repositories at a time should invoke only
 "reposetup()" of extensions enabling in the target repository.
 
   $ mkdir reposetup-test
   $ cd reposetup-test
 
   $ cat > $TESTTMP/reposetuptest.py <<EOF
   > from mercurial import extensions
   > def reposetup(ui, repo):
   >     ui.write('reposetup() for %s\n' % (repo.root))
   >     ui.flush()
   > EOF
   $ hg init src
   $ echo a > src/a
   $ hg -R src commit -Am '#0 at src/a'
   adding a
   $ echo '[extensions]' >> src/.hg/hgrc
   $ echo '# enable extension locally' >> src/.hg/hgrc
   $ echo "reposetuptest = $TESTTMP/reposetuptest.py" >> src/.hg/hgrc
   $ hg -R src status
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ hg clone -U src clone-dst1
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init push-dst1
   $ hg -q -R src push push-dst1
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init pull-src1
   $ hg -q -R pull-src1 pull src
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # disable extension globally and explicitly
   > reposetuptest = !
   > EOF
   $ hg clone -U src clone-dst2
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init push-dst2
   $ hg -q -R src push push-dst2
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   $ hg init pull-src2
   $ hg -q -R pull-src2 pull src
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # enable extension globally
   > reposetuptest = $TESTTMP/reposetuptest.py
   > EOF
   $ hg clone -U src clone-dst3
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   reposetup() for $TESTTMP/reposetup-test/clone-dst3 (glob)
   $ hg init push-dst3
   reposetup() for $TESTTMP/reposetup-test/push-dst3 (glob)
   $ hg -q -R src push push-dst3
   reposetup() for $TESTTMP/reposetup-test/src (glob)
   reposetup() for $TESTTMP/reposetup-test/push-dst3 (glob)
   $ hg init pull-src3
   reposetup() for $TESTTMP/reposetup-test/pull-src3 (glob)
   $ hg -q -R pull-src3 pull src
   reposetup() for $TESTTMP/reposetup-test/pull-src3 (glob)
   reposetup() for $TESTTMP/reposetup-test/src (glob)
 
   $ echo '[extensions]' >> src/.hg/hgrc
   $ echo '# disable extension locally' >> src/.hg/hgrc
   $ echo 'reposetuptest = !' >> src/.hg/hgrc
   $ hg clone -U src clone-dst4
   reposetup() for $TESTTMP/reposetup-test/clone-dst4 (glob)
   $ hg init push-dst4
   reposetup() for $TESTTMP/reposetup-test/push-dst4 (glob)
   $ hg -q -R src push push-dst4
   reposetup() for $TESTTMP/reposetup-test/push-dst4 (glob)
   $ hg init pull-src4
   reposetup() for $TESTTMP/reposetup-test/pull-src4 (glob)
   $ hg -q -R pull-src4 pull src
   reposetup() for $TESTTMP/reposetup-test/pull-src4 (glob)
 
 disabling in command line overlays with all configuration
   $ hg --config extensions.reposetuptest=! clone -U src clone-dst5
   $ hg --config extensions.reposetuptest=! init push-dst5
   $ hg --config extensions.reposetuptest=! -q -R src push push-dst5
   $ hg --config extensions.reposetuptest=! init pull-src5
   $ hg --config extensions.reposetuptest=! -q -R pull-src5 pull src
 
   $ cat <<EOF >> $HGRCPATH
   > [extensions]
   > # disable extension globally and explicitly
   > reposetuptest = !
   > EOF
   $ hg init parent
   $ hg init parent/sub1
   $ echo 1 > parent/sub1/1
   $ hg -R parent/sub1 commit -Am '#0 at parent/sub1'
   adding 1
   $ hg init parent/sub2
   $ hg init parent/sub2/sub21
   $ echo 21 > parent/sub2/sub21/21
   $ hg -R parent/sub2/sub21 commit -Am '#0 at parent/sub2/sub21'
   adding 21
   $ cat > parent/sub2/.hgsub <<EOF
   > sub21 = sub21
   > EOF
   $ hg -R parent/sub2 commit -Am '#0 at parent/sub2'
   adding .hgsub
   $ hg init parent/sub3
   $ echo 3 > parent/sub3/3
   $ hg -R parent/sub3 commit -Am '#0 at parent/sub3'
   adding 3
   $ cat > parent/.hgsub <<EOF
   > sub1 = sub1
   > sub2 = sub2
   > sub3 = sub3
   > EOF
   $ hg -R parent commit -Am '#0 at parent'
   adding .hgsub
   $ echo '[extensions]' >> parent/.hg/hgrc
   $ echo '# enable extension locally' >> parent/.hg/hgrc
   $ echo "reposetuptest = $TESTTMP/reposetuptest.py" >> parent/.hg/hgrc
   $ cp parent/.hg/hgrc parent/sub2/.hg/hgrc
   $ hg -R parent status -S -A
   reposetup() for $TESTTMP/reposetup-test/parent (glob)
   reposetup() for $TESTTMP/reposetup-test/parent/sub2 (glob)
   C .hgsub
   C .hgsubstate
   C sub1/1
   C sub2/.hgsub
   C sub2/.hgsubstate
   C sub2/sub21/21
   C sub3/3
 
   $ cd ..
 
 Prohibit registration of commands that don't use @command (issue5137)
 
   $ hg init deprecated
   $ cd deprecated
 
   $ cat <<EOF > deprecatedcmd.py
   > def deprecatedcmd(repo, ui):
   >     pass
   > cmdtable = {
   >     'deprecatedcmd': (deprecatedcmd, [], ''),
   > }
   > EOF
   $ cat <<EOF > .hg/hgrc
   > [extensions]
   > deprecatedcmd = `pwd`/deprecatedcmd.py
   > mq = !
   > hgext.mq = !
   > hgext/mq = !
   > EOF
 
   $ hg deprecatedcmd > /dev/null
   *** failed to import extension deprecatedcmd from $TESTTMP/deprecated/deprecatedcmd.py: missing attributes: norepo, optionalrepo, inferrepo
   *** (use @command decorator to register 'deprecatedcmd')
   hg: unknown command 'deprecatedcmd'
   [255]
 
  the extension shouldn't be loaded at all so the mq works:
 
   $ hg qseries --config extensions.mq= > /dev/null
   *** failed to import extension deprecatedcmd from $TESTTMP/deprecated/deprecatedcmd.py: missing attributes: norepo, optionalrepo, inferrepo
   *** (use @command decorator to register 'deprecatedcmd')
 
   $ cd ..
 
 Test synopsis and docstring extending
 
   $ hg init exthelp
   $ cat > exthelp.py <<EOF
   > from mercurial import commands, extensions
   > def exbookmarks(orig, *args, **opts):
   >     return orig(*args, **opts)
   > def uisetup(ui):
   >     synopsis = ' GREPME [--foo] [-x]'
   >     docstring = '''
   >     GREPME make sure that this is in the help!
   >     '''
   >     extensions.wrapcommand(commands.table, 'bookmarks', exbookmarks,
   >                            synopsis, docstring)
   > EOF
   $ abspath=`pwd`/exthelp.py
   $ echo '[extensions]' >> $HGRCPATH
   $ echo "exthelp = $abspath" >> $HGRCPATH
   $ cd exthelp
   $ hg help bookmarks | grep GREPME
   hg bookmarks [OPTIONS]... [NAME]... GREPME [--foo] [-x]
       GREPME make sure that this is in the help!
   $ cd ..
 
 Show deprecation warning for the use of cmdutil.command
 
   $ cat > nonregistrar.py <<EOF
   > from mercurial import cmdutil
   > cmdtable = {}
   > command = cmdutil.command(cmdtable)
   > @command('foo', [], norepo=True)
   > def foo(ui):
   >     pass
   > EOF
 
   $ hg --config extensions.nonregistrar=`pwd`/nonregistrar.py version > /dev/null
   devel-warn: cmdutil.command is deprecated, use registrar.command to register 'foo'
   (compatibility will be dropped after Mercurial-4.6, update your code.) * (glob)
 
 Make sure a broken uisetup doesn't globally break hg:
   $ cat > baduisetup.py <<EOF
   > from mercurial import (
   >     bdiff,
   >     extensions,
   > )
   > 
   > def blockswrapper(orig, *args, **kwargs):
   >     return orig(*args, **kwargs)
   > 
   > def uisetup(ui):
   >     extensions.wrapfunction(bdiff, 'blocks', blockswrapper)
   > EOF
   $ cat >> $HGRCPATH <<EOF
   > [extensions]
   > baduisetup = $PWD/baduisetup.py
   > EOF
 
-Broken: an extension that triggers the import of bdiff during uisetup
-can't be easily debugged:
+Even though the extension fails during uisetup, hg is still basically usable:
   $ hg version
-  abort: No module named bdiff!
-  (did you forget to compile extensions?)
-  [255]
+  *** failed to set up extension baduisetup: No module named bdiff
+  Mercurial Distributed SCM (version *) (glob)
+  (see https://mercurial-scm.org for more information)
+  
+  Copyright (C) 2005-2017 Matt Mackall and others
+  This is free software; see the source for copying conditions. There is NO
+  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+
+  $ hg version --traceback
+  Traceback (most recent call last):
+    File "*/mercurial/extensions.py", line *, in _runuisetup (glob)
+      uisetup(ui)
+    File "$TESTTMP/baduisetup.py", line 10, in uisetup
+      extensions.wrapfunction(bdiff, 'blocks', blockswrapper)
+    File "*/mercurial/extensions.py", line *, in wrapfunction (glob)
+      origfn = getattr(container, funcname)
+    File "*/hgdemandimport/demandimportpy2.py", line *, in __getattr__ (glob)
+      self._load()
+    File "*/hgdemandimport/demandimportpy2.py", line *, in _load (glob)
+      mod = _hgextimport(_import, head, globals, locals, None, level)
+    File "*/hgdemandimport/demandimportpy2.py", line *, in _hgextimport (glob)
+      return importfunc(name, globals, *args, **kwargs)
+  ImportError: No module named bdiff
+  *** failed to set up extension baduisetup: No module named bdiff
+  Mercurial Distributed SCM (version *) (glob)
+  (see https://mercurial-scm.org for more information)
+  
+  Copyright (C) 2005-2017 Matt Mackall and others
+  This is free software; see the source for copying conditions. There is NO
+  warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

tests/test-flagprocessor.t

@@ -1,247 +1,248 b''
 # Create server
   $ hg init server
   $ cd server
   $ cat >> .hg/hgrc << EOF
   > [extensions]
   > extension=$TESTDIR/flagprocessorext.py
   > EOF
   $ cd ../
 
 # Clone server and enable extensions
   $ hg clone -q server client
   $ cd client
   $ cat >> .hg/hgrc << EOF
   > [extensions]
   > extension=$TESTDIR/flagprocessorext.py
   > EOF
 
 # Commit file that will trigger the noop extension
   $ echo '[NOOP]' > noop
   $ hg commit -Aqm "noop"
 
 # Commit file that will trigger the base64 extension
   $ echo '[BASE64]' > base64
   $ hg commit -Aqm 'base64'
 
 # Commit file that will trigger the gzip extension
   $ echo '[GZIP]' > gzip
   $ hg commit -Aqm 'gzip'
 
 # Commit file that will trigger noop and base64
   $ echo '[NOOP][BASE64]' > noop-base64
   $ hg commit -Aqm 'noop+base64'
 
 # Commit file that will trigger noop and gzip
   $ echo '[NOOP][GZIP]' > noop-gzip
   $ hg commit -Aqm 'noop+gzip'
 
 # Commit file that will trigger base64 and gzip
   $ echo '[BASE64][GZIP]' > base64-gzip
   $ hg commit -Aqm 'base64+gzip'
 
 # Commit file that will trigger base64, gzip and noop
   $ echo '[BASE64][GZIP][NOOP]' > base64-gzip-noop
   $ hg commit -Aqm 'base64+gzip+noop'
 
 # TEST: ensure the revision data is consistent
   $ hg cat noop
   [NOOP]
   $ hg debugdata noop 0
   [NOOP]
 
   $ hg cat -r . base64
   [BASE64]
   $ hg debugdata base64 0
   W0JBU0U2NF0K (no-eol)
 
   $ hg cat -r . gzip
   [GZIP]
   $ hg debugdata gzip 0
   x\x9c\x8bv\x8f\xf2\x0c\x88\xe5\x02\x00\x08\xc8\x01\xfd (no-eol) (esc)
 
   $ hg cat -r . noop-base64
   [NOOP][BASE64]
   $ hg debugdata noop-base64 0
   W05PT1BdW0JBU0U2NF0K (no-eol)
 
   $ hg cat -r . noop-gzip
   [NOOP][GZIP]
   $ hg debugdata noop-gzip 0
   x\x9c\x8b\xf6\xf3\xf7\x0f\x88\x8dv\x8f\xf2\x0c\x88\xe5\x02\x00\x1dH\x03\xf1 (no-eol) (esc)
 
   $ hg cat -r . base64-gzip
   [BASE64][GZIP]
   $ hg debugdata base64-gzip 0
   eJyLdnIMdjUziY12j/IMiOUCACLBBDo= (no-eol)
 
   $ hg cat -r . base64-gzip-noop
   [BASE64][GZIP][NOOP]
   $ hg debugdata base64-gzip-noop 0
   eJyLdnIMdjUziY12j/IMiI328/cPiOUCAESjBi4= (no-eol)
 
 # Push to the server
   $ hg push
   pushing to $TESTTMP/server (glob)
   searching for changes
   adding changesets
   adding manifests
   adding file changes
   added 7 changesets with 7 changes to 7 files
 
 # Initialize new client (not cloning) and setup extension
   $ cd ..
   $ hg init client2
   $ cd client2
   $ cat >> .hg/hgrc << EOF
   > [paths]
   > default = $TESTTMP/server
   > [extensions]
   > extension=$TESTDIR/flagprocessorext.py
   > EOF
 
 # Pull from server and update to latest revision
   $ hg pull default
   pulling from $TESTTMP/server (glob)
   requesting all changes
   adding changesets
   adding manifests
   adding file changes
   added 7 changesets with 7 changes to 7 files
   (run 'hg update' to get a working copy)
   $ hg update
   7 files updated, 0 files merged, 0 files removed, 0 files unresolved
 
 # TEST: ensure the revision data is consistent
   $ hg cat noop
   [NOOP]
   $ hg debugdata noop 0
   [NOOP]
 
   $ hg cat -r . base64
   [BASE64]
   $ hg debugdata base64 0
   W0JBU0U2NF0K (no-eol)
 
   $ hg cat -r . gzip
   [GZIP]
   $ hg debugdata gzip 0
   x\x9c\x8bv\x8f\xf2\x0c\x88\xe5\x02\x00\x08\xc8\x01\xfd (no-eol) (esc)
 
   $ hg cat -r . noop-base64
   [NOOP][BASE64]
   $ hg debugdata noop-base64 0
   W05PT1BdW0JBU0U2NF0K (no-eol)
 
   $ hg cat -r . noop-gzip
   [NOOP][GZIP]
   $ hg debugdata noop-gzip 0
   x\x9c\x8b\xf6\xf3\xf7\x0f\x88\x8dv\x8f\xf2\x0c\x88\xe5\x02\x00\x1dH\x03\xf1 (no-eol) (esc)
 
   $ hg cat -r . base64-gzip
   [BASE64][GZIP]
   $ hg debugdata base64-gzip 0
   eJyLdnIMdjUziY12j/IMiOUCACLBBDo= (no-eol)
 
   $ hg cat -r . base64-gzip-noop
   [BASE64][GZIP][NOOP]
   $ hg debugdata base64-gzip-noop 0
   eJyLdnIMdjUziY12j/IMiI328/cPiOUCAESjBi4= (no-eol)
 
 # TEST: ensure a missing processor is handled
   $ echo '[FAIL][BASE64][GZIP][NOOP]' > fail-base64-gzip-noop
   $ hg commit -Aqm 'fail+base64+gzip+noop'
   abort: missing processor for flag '0x1'!
   [255]
 
 # TEST: ensure we cannot register several flag processors on the same flag
   $ cat >> .hg/hgrc << EOF
   > [extensions]
   > extension=$TESTDIR/flagprocessorext.py
   > duplicate=$TESTDIR/flagprocessorext.py
   > EOF
   $ echo 'this should fail' > file
   $ hg commit -Aqm 'add file'
-  abort: cannot register multiple processors on flag '0x8'.
+  *** failed to set up extension duplicate: cannot register multiple processors on flag '0x8'.
+  abort: missing processor for flag '0x1'!
   [255]
 
   $ cd ..
 
 # TEST: bundle repo
   $ hg init bundletest
   $ cd bundletest
 
   $ cat >> .hg/hgrc << EOF
   > [extensions]
   > flagprocessor=$TESTDIR/flagprocessorext.py
   > EOF
 
   $ for i in 0 single two three 4; do
   >   echo '[BASE64]a-bit-longer-'$i > base64
   >   hg commit -m base64-$i -A base64
   > done
 
   $ hg update 2 -q
   $ echo '[BASE64]a-bit-longer-branching' > base64
   $ hg commit -q -m branching
 
   $ hg bundle --base 1 bundle.hg
   4 changesets found
   $ hg --config extensions.strip= strip -r 2 --no-backup --force -q
   $ hg -R bundle.hg log --stat -T '{rev} {desc}\n' base64
   5 branching
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   4 base64-4
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   3 base64-three
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   2 base64-two
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   1 base64-single
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   0 base64-0
    base64 |  1 +
    1 files changed, 1 insertions(+), 0 deletions(-)
   
 
   $ hg bundle -R bundle.hg --base 1 bundle-again.hg -q
   $ hg -R bundle-again.hg log --stat -T '{rev} {desc}\n' base64
   5 branching
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   4 base64-4
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   3 base64-three
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   2 base64-two
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   1 base64-single
    base64 |  2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)
   
   0 base64-0
    base64 |  1 +
    1 files changed, 1 insertions(+), 0 deletions(-)
   
   $ rm bundle.hg bundle-again.hg
 
 # TEST: hg status
 
   $ hg status
   $ hg diff