diff -r c07974215b3d -r de1e7099d100 mercurial/extensions.py
--- a/mercurial/extensions.py	Sun Feb 07 11:32:08 2010 +0100
+++ b/mercurial/extensions.py	Sun Feb 07 14:01:43 2010 +0100
@@ -6,7 +6,7 @@
 # GNU General Public License version 2 or any later version.
 
 import imp, os
-import util, cmdutil, help
+import util, cmdutil, help, error
 from i18n import _, gettext
 
 _extensions = {}
@@ -131,8 +131,9 @@
     setattr(container, funcname, wrap)
     return origfn
 
-def _disabledpaths():
-    '''find paths of disabled extensions. returns a dict of {name: path}'''
+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(hgext.__file__))
     try: # might not be a filesystem path
@@ -150,6 +151,8 @@
             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
@@ -191,6 +194,53 @@
 
     return exts, maxlength
 
+def disabledext(name):
+    '''find a specific disabled extension from hgext. returns desc'''
+    paths = _disabledpaths()
+    if name in paths:
+        return _disabledhelp(paths[name])
+
+def disabledcmd(cmd, strict=False):
+    '''import disabled extensions until cmd is found.
+    returns (cmdname, extname, doc)'''
+
+    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
+        for c in aliases:
+            if c.startswith(cmd):
+                cmd = c
+                break
+        else:
+            cmd = aliases[0]
+        return (cmd, name, mod)
+
+    # 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 ext:
+            return ext
+
+    # otherwise, interrogate each extension until there's a match
+    for name, path in paths.iteritems():
+        ext = findcmd(cmd, name, path)
+        if ext:
+            return ext
+
+    raise error.UnknownCommand(cmd)
+
 def enabled():
     '''return a dict of {name: desc} of extensions, and the max name length'''
     exts = {}