extdiff: escape filenames with vim/DirDiff and make quoting work with Windows

Use vim function fnameescape() on filenames.
Use double quotes for arguments so cmd.exe is happy.

contrib/win32/mercurial.ini

@@ -1,93 +1,93 b''
 ; System-wide Mercurial config file.
 ;
 ; !!!  Do Not Edit This File !!!
 ;
 ; This file will be replaced by the installer on every upgrade.
 ; Editing this file can cause strange side effects on Vista.
 ;
 ; http://bitbucket.org/tortoisehg/stable/issue/135
 ;
 ; To change settings you see in this file, override (or enable) them in
 ; your user Mercurial.ini file, where USERNAME is your Windows user name:
 ;
 ; XP or older    - C:\Documents and Settings\USERNAME\Mercurial.ini
 ; Vista or later - C:\Users\USERNAME\Mercurial.ini
 
 
 [ui]
 ; editor used to enter commit logs, etc.  Most text editors will work.
 editor = notepad
 ; show changed files and be a bit more verbose if True
 ; verbose = True
  
 ; username data to appear in commits
 ; it usually takes the form: Joe User <[e-mail]>
 ; username = Joe User <[e-mail]>
 
 ; In order to push/pull over ssh you must specify an ssh tool
 ;ssh = "C:\Progra~1\TortoiseSVN\bin\TortoisePlink.exe" -ssh -2
 ;ssh = C:\cygwin\bin\ssh
 
 ;
 ; For more information about mercurial extensions, start here
 ; http://www.selenic.com/mercurial/wiki/index.cgi/UsingExtensions
 ;
 ; Extensions shipped with Mercurial
 ;
 [extensions]
 ;acl =
 ;alias =
 ;bugzilla =
 ;children =
 ;churn =
 ;color =
 ;convert =
 ;eol =
 ;extdiff =
 ;fetch =
 ;gpg =
 ;graphlog = 
 ;hgcia =
 ;hgk =
 ;highlight = 
 ;interhg =
 ;keyword =
 ;mq =
 ;notify =
 ;pager =
 ;patchbomb =
 ;progress =
 ;purge =
 ;rebase =
 ;record =
 ;transplant =
 ;win32mbcs =
 ;zeroconf =
 
 ;
 ; Define external diff commands
 ;
 [extdiff]
 ;cmd.bc3diff = C:\Program Files\Beyond Compare 3\BCompare.exe
 ;cmd.vdiff = C:\Progra~1\TortoiseSVN\bin\TortoiseMerge.exe
 ;cmd.vimdiff = gvim.exe
-;opts.vimdiff = -f '+next' '+execute "DirDiff ".argv(0)." ".argv(1)'
+;opts.vimdiff = -f "+next" "+execute 'DirDiff' fnameescape(argv(0)) fnameescape(argv(1))"
 
 
 [hgk]
 ; Replace the following with your path to hgk, uncomment it and 
 ; install ActiveTcl (or another win32 port like tclkit)
 ; path="C:\Program Files\Mercurial\Contrib\hgk.tcl"
 ; vdiff=vdiff
  
 
 ;
 ; The git extended diff format can represent binary files, file
 ; permission changes, and rename information that the normal patch format
 ; cannot describe.  However it is also not compatible with tools which
 ; expect normal patches. so enable git patches at your own risk.
 ;
 [diff]
 ;git = false
 ;nodates = false
 

hgext/extdiff.py

@@ -1,328 +1,329 b''
 # extdiff.py - external diff program support for mercurial
 #
 # Copyright 2006 Vadim Gelfer <[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.
 
 '''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 vdiff, runs kdiff3
   vdiff = kdiff3
 
   # add new command called meld, runs meld (no need to name twice)
   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" argv(0) argv(1)'
+  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).
 '''
 
 from mercurial.i18n import _
 from mercurial.node import short, nullid
 from mercurial import scmutil, scmutil, util, commands, encoding
 import os, shlex, shutil, tempfile, re
 
 def snapshot(ui, repo, files, node, tmproot):
     '''snapshot files as of some revision
     if not using snapshot, -I/-X does not work and recursive diff
     in tools like kdiff3 and meld displays too many files.'''
     dirname = os.path.basename(repo.root)
     if dirname == "":
         dirname = "root"
     if node is not None:
         dirname = '%s.%s' % (dirname, short(node))
     base = os.path.join(tmproot, dirname)
     os.mkdir(base)
     if node is not None:
         ui.note(_('making snapshot of %d files from rev %s\n') %
                 (len(files), short(node)))
     else:
         ui.note(_('making snapshot of %d files from working directory\n') %
             (len(files)))
     wopener = scmutil.opener(base)
     fns_and_mtime = []
     ctx = repo[node]
     for fn in files:
         wfn = util.pconvert(fn)
         if not wfn in ctx:
             # File doesn't exist; could be a bogus modify
             continue
         ui.note('  %s\n' % wfn)
         dest = os.path.join(base, wfn)
         fctx = ctx[wfn]
         data = repo.wwritedata(wfn, fctx.data())
         if 'l' in fctx.flags():
             wopener.symlink(data, wfn)
         else:
             wopener.write(wfn, data)
             if 'x' in fctx.flags():
                 util.setflags(dest, False, True)
         if node is None:
             fns_and_mtime.append((dest, repo.wjoin(fn),
                                   os.lstat(dest).st_mtime))
     return dirname, fns_and_mtime
 
 def dodiff(ui, repo, diffcmd, diffopts, pats, opts):
     '''Do the actuall diff:
 
     - copy to a temp structure if diffing 2 internal revisions
     - copy to a temp structure if diffing working revision with
       another one and more than 1 file is changed
     - just invoke the diff for a single file in the working dir
     '''
 
     revs = opts.get('rev')
     change = opts.get('change')
     args = ' '.join(diffopts)
     do3way = '$parent2' in args
 
     if revs and change:
         msg = _('cannot specify --rev and --change at the same time')
         raise util.Abort(msg)
     elif change:
         node2 = scmutil.revsingle(repo, change, None).node()
         node1a, node1b = repo.changelog.parents(node2)
     else:
         node1a, node2 = scmutil.revpair(repo, revs)
         if not revs:
             node1b = repo.dirstate.p2()
         else:
             node1b = nullid
 
     # Disable 3-way merge if there is only one parent
     if do3way:
         if node1b == nullid:
             do3way = False
 
     matcher = scmutil.match(repo[node2], pats, opts)
     mod_a, add_a, rem_a = map(set, repo.status(node1a, node2, matcher)[:3])
     if do3way:
         mod_b, add_b, rem_b = map(set, repo.status(node1b, node2, matcher)[:3])
     else:
         mod_b, add_b, rem_b = set(), set(), set()
     modadd = mod_a | add_a | mod_b | add_b
     common = modadd | rem_a | rem_b
     if not common:
         return 0
 
     tmproot = tempfile.mkdtemp(prefix='extdiff.')
     try:
         # Always make a copy of node1a (and node1b, if applicable)
         dir1a_files = mod_a | rem_a | ((mod_b | add_b) - add_a)
         dir1a = snapshot(ui, repo, dir1a_files, node1a, tmproot)[0]
         rev1a = '@%d' % repo[node1a].rev()
         if do3way:
             dir1b_files = mod_b | rem_b | ((mod_a | add_a) - add_b)
             dir1b = snapshot(ui, repo, dir1b_files, node1b, tmproot)[0]
             rev1b = '@%d' % repo[node1b].rev()
         else:
             dir1b = None
             rev1b = ''
 
         fns_and_mtime = []
 
         # If node2 in not the wc or there is >1 change, copy it
         dir2root = ''
         rev2 = ''
         if node2:
             dir2 = snapshot(ui, repo, modadd, node2, tmproot)[0]
             rev2 = '@%d' % repo[node2].rev()
         elif len(common) > 1:
             #we only actually need to get the files to copy back to
             #the working dir in this case (because the other cases
             #are: diffing 2 revisions or single file -- in which case
             #the file is already directly passed to the diff tool).
             dir2, fns_and_mtime = snapshot(ui, repo, modadd, None, tmproot)
         else:
             # This lets the diff tool open the changed file directly
             dir2 = ''
             dir2root = repo.root
 
         label1a = rev1a
         label1b = rev1b
         label2 = rev2
 
         # If only one change, diff the files instead of the directories
         # Handle bogus modifies correctly by checking if the files exist
         if len(common) == 1:
             common_file = util.localpath(common.pop())
             dir1a = os.path.join(tmproot, dir1a, common_file)
             label1a = common_file + rev1a
             if not os.path.isfile(dir1a):
                 dir1a = os.devnull
             if do3way:
                 dir1b = os.path.join(tmproot, dir1b, common_file)
                 label1b = common_file + rev1b
                 if not os.path.isfile(dir1b):
                     dir1b = os.devnull
             dir2 = os.path.join(dir2root, dir2, common_file)
             label2 = common_file + rev2
 
         # Function to quote file/dir names in the argument string.
         # When not operating in 3-way mode, an empty string is
         # returned for parent2
         replace = dict(parent=dir1a, parent1=dir1a, parent2=dir1b,
                        plabel1=label1a, plabel2=label1b,
                        clabel=label2, child=dir2,
                        root=repo.root)
         def quote(match):
             key = match.group()[1:]
             if not do3way and key == 'parent2':
                 return ''
             return util.shellquote(replace[key])
 
         # Match parent2 first, so 'parent1?' will match both parent1 and parent
         regex = '\$(parent2|parent1?|child|plabel1|plabel2|clabel|root)'
         if not do3way and not re.search(regex, args):
             args += ' $parent1 $child'
         args = re.sub(regex, quote, args)
         cmdline = util.shellquote(diffcmd) + ' ' + args
 
         ui.debug('running %r in %s\n' % (cmdline, tmproot))
         util.system(cmdline, cwd=tmproot, out=ui.fout)
 
         for copy_fn, working_fn, mtime in fns_and_mtime:
             if os.lstat(copy_fn).st_mtime != mtime:
                 ui.debug('file changed while diffing. '
                          'Overwriting: %s (src: %s)\n' % (working_fn, copy_fn))
                 util.copyfile(copy_fn, working_fn)
 
         return 1
     finally:
         ui.note(_('cleaning up temp directory\n'))
         shutil.rmtree(tmproot)
 
 def extdiff(ui, repo, *pats, **opts):
     '''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.'''
     program = opts.get('program')
     option = opts.get('option')
     if not program:
         program = 'diff'
         option = option or ['-Npru']
     return dodiff(ui, repo, program, option, pats, opts)
 
 cmdtable = {
     "extdiff":
     (extdiff,
      [('p', 'program', '',
        _('comparison program to run'), _('CMD')),
       ('o', 'option', [],
        _('pass option to comparison program'), _('OPT')),
       ('r', 'rev', [],
        _('revision'), _('REV')),
       ('c', 'change', '',
        _('change made by revision'), _('REV')),
      ] + commands.walkopts,
      _('hg extdiff [OPT]... [FILE]...')),
     }
 
 def uisetup(ui):
     for cmd, path in ui.configitems('extdiff'):
         if cmd.startswith('cmd.'):
             cmd = cmd[4:]
             if not path:
                 path = cmd
             diffopts = ui.config('extdiff', 'opts.' + cmd, '')
             diffopts = diffopts and [diffopts] or []
         elif cmd.startswith('opts.'):
             continue
         else:
             # command = path opts
             if path:
                 diffopts = shlex.split(path)
                 path = diffopts.pop(0)
             else:
                 path, diffopts = cmd, []
         # look for diff arguments in [diff-tools] then [merge-tools]
         if diffopts == []:
             args = ui.config('diff-tools', cmd+'.diffargs') or \
                    ui.config('merge-tools', cmd+'.diffargs')
             if args:
                 diffopts = shlex.split(args)
         def save(cmd, path, diffopts):
             '''use closure to save diff command to use'''
             def mydiff(ui, repo, *pats, **opts):
                 return dodiff(ui, repo, path, diffopts + opts['option'],
                               pats, opts)
             doc = _('''\
 use %(path)s to diff repository (or selected files)
 
     Show differences between revisions for the specified files, using
     the %(path)s program.
 
     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.\
 ''') % dict(path=util.uirepr(path))
 
             # We must translate the docstring right away since it is
             # used as a format string. The string will unfortunately
             # be translated again in commands.helpcmd and this will
             # fail when the docstring contains non-ASCII characters.
             # Decoding the string to a Unicode string here (using the
             # right encoding) prevents that.
             mydiff.__doc__ = doc.decode(encoding.encoding)
             return mydiff
         cmdtable[cmd] = (save(cmd, path, diffopts),
                          cmdtable['extdiff'][1][1:],
                          _('hg %s [OPTION]... [FILE]...') % cmd)

tests/test-extension.t

@@ -1,479 +1,480 b''
 Test basic extension support
 
   $ "$TESTDIR/hghave" no-outer-repo || exit 80
 
   $ cat > foobar.py <<EOF
   > import os
   > from mercurial import commands
   > 
   > def uisetup(ui):
   >     ui.write("uisetup called\\n")
   > 
   > 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 "!"))
   > 
   > def foo(ui, *args, **kwargs):
   >     ui.write("Foo\\n")
   > 
   > def bar(ui, *args, **kwargs):
   >     ui.write("Bar\\n")
   > 
   > cmdtable = {
   >    "foo": (foo, [], "hg foo"),
   >    "bar": (bar, [], "hg bar"),
   > }
   > 
   > commands.norepo += ' bar'
   > 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
 
   $ SCRIPT_NAME='/' 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
   4) foo reposetup
   4) bar reposetup
 
   $ echo 'foo = !' >> $HGRCPATH
   $ echo 'bar = !' >> $HGRCPATH
 
   $ cd ..
 
   $ 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
   > '''
   > def debugfoobar(ui, repo, *args, **opts):
   >     "yet another debug command"
   >     pass
   > 
   > def foo(ui, repo, *args, **opts):
   >     """yet another foo command
   > 
   >     This command has been DEPRECATED since forever.
   >     """
   >     pass
   > 
   > cmdtable = {
   >    "debugfoobar": (debugfoobar, (), "hg debugfoobar"),
   >    "foo": (foo, (), "hg foo")
   > }
   > EOF
   $ debugpath=`pwd`/debugextension.py
   $ echo "debugextension = $debugpath" >> $HGRCPATH
 
   $ hg help debugextension
   debugextension extension - only debugcommands
   
   no commands defined
 
   $ hg --verbose help debugextension
   debugextension extension - only debugcommands
   
   list of commands:
   
    foo:
         yet another foo command
   
   global options:
   
    -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
       --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
   
   [+] marked option can be specified multiple times
 
   $ hg --debug help debugextension
   debugextension extension - only debugcommands
   
   list of commands:
   
    debugfoobar:
         yet another debug command
    foo:
         yet another foo command
   
   global options:
   
    -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
       --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
   
   [+] marked option can be specified multiple times
   $ echo 'debugextension = !' >> $HGRCPATH
 
 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:
   
    -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
    -I --include PATTERN [+] include names matching the given patterns
    -X --exclude PATTERN [+] exclude names matching the given patterns
   
   [+] marked option can be specified multiple times
   
   use "hg -v help extdiff" to show more info
 
   $ 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 vdiff, runs kdiff3
     vdiff = kdiff3
   
     # add new command called meld, runs meld (no need to name twice)
     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" argv(0) argv(1)'
+    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 -v help extdiff" to show builtin aliases and global options
 
   $ echo 'extdiff = !' >> $HGRCPATH
 
 Test help topic with same name as extension
 
   $ cat > multirevs.py <<EOF
   > from mercurial import commands
   > """multirevs extension
   > Big multi-line module docstring."""
   > def multirevs(ui, repo, arg, *args, **opts):
   >     """multirevs command"""
   >     pass
   > cmdtable = {
   >    "multirevs": (multirevs, [], 'ARG')
   > }
   > commands.norepo += ' multirevs'
   > EOF
   $ echo "multirevs = multirevs.py" >> $HGRCPATH
 
   $ hg help multirevs
   Specifying Multiple Revisions
   
       When Mercurial accepts more than one revision, they may be specified
       individually, or provided as a topologically continuous range, separated
       by the ":" character.
   
       The syntax of range notation is [BEGIN]:[END], where BEGIN and END are
       revision identifiers. Both BEGIN and END are optional. If BEGIN is not
       specified, it defaults to revision number 0. If END is not specified, it
       defaults to the tip. The range ":" thus means "all revisions".
   
       If BEGIN is greater than END, revisions are treated in reverse order.
   
       A range acts as a closed interval. This means that a range of 3:5 gives 3,
       4 and 5. Similarly, a range of 9:6 gives 9, 8, 7, and 6.
   
   use "hg help -c multirevs" to see help for the multirevs command
 
   $ hg help -c multirevs
   hg multirevs ARG
   
   multirevs command
   
   use "hg -v help multirevs" to show more info
 
   $ hg multirevs
   hg multirevs: invalid arguments
   hg multirevs ARG
   
   multirevs command
   
   use "hg help multirevs" to show the full help text
   [255]
 
   $ echo "multirevs = !" >> $HGRCPATH
 
 Issue811: Problem loading extensions twice (by site and by user)
 
   $ debugpath=`pwd`/debugissue811.py
   $ cat > debugissue811.py <<EOF
   > '''show all loaded extensions
   > '''
   > from mercurial import extensions, commands
   > 
   > def debugextensions(ui):
   >     "yet another debug command"
   >     ui.write("%s\n" % '\n'.join([x for x, y in extensions.extensions()]))
   > 
   > cmdtable = {"debugextensions": (debugextensions, (), "hg debugextensions")}
   > commands.norepo += " debugextensions"
   > EOF
   $ echo "debugissue811 = $debugpath" >> $HGRCPATH
   $ echo "mq=" >> $HGRCPATH
   $ echo "hgext.mq=" >> $HGRCPATH
   $ echo "hgext/mq=" >> $HGRCPATH
 
 Show extensions:
 
   $ hg debugextensions
   debugissue811
   mq
 
 Disabled extension commands:
 
   $ 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
   
   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)
   hg: unknown command 'foo'
   warning: error finding commands in $TESTTMP/hgext/forest.py (glob)
   [255]