Allow explicit disabling of extensions

If the first character of an extension path is '!', the extension
is silently skipped.

mercurial/extensions.py

@@ -1,83 +1,85 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, incorporated herein by reference.
 
 import imp, os
 import util, sys
 from i18n import _
 
 _extensions = {}
 _order = []
 
 def extensions():
     for name in _order:
         module = _extensions[name]
         if module:
             yield name, module
 
 def find(name):
     '''return module with given extension name'''
     try:
         return _extensions[name]
     except KeyError:
         for k, v in _extensions.iteritems():
             if k.endswith('.' + name) or k.endswith('/' + name):
                 return v
         raise KeyError(name)
 
 def load(ui, name, path):
     if name.startswith('hgext.'):
         shortname = name[6:]
     else:
         shortname = name
     if shortname in _extensions:
         return
     _extensions[shortname] = None
     if path:
         # the module will be loaded in sys.modules
         # choose an unique name so that it doesn't
         # conflicts with other modules
         module_name = "hgext_%s" % name.replace('.', '_')
         if os.path.isdir(path):
             # module/__init__.py style
             d, f = os.path.split(path)
             fd, fpath, desc = imp.find_module(f, [d])
             mod = imp.load_module(module_name, fd, fpath, desc)
         else:
             mod = imp.load_source(module_name, path)
     else:
         def importh(name):
             mod = __import__(name)
             components = name.split('.')
             for comp in components[1:]:
                 mod = getattr(mod, comp)
             return mod
         try:
             mod = importh("hgext.%s" % name)
         except ImportError:
             mod = importh(name)
     _extensions[shortname] = mod
     _order.append(shortname)
 
     uisetup = getattr(mod, 'uisetup', None)
     if uisetup:
         uisetup(ui)
 
 def loadall(ui):
     result = ui.configitems("extensions")
     for i, (name, path) in enumerate(result):
         if path:
+            if path[0] == '!':
+                continue
             path = os.path.expanduser(path)
         try:
             load(ui, name, path)
         except (util.SignalInterrupt, KeyboardInterrupt):
             raise
         except Exception, inst:
             ui.warn(_("*** failed to import extension %s: %s\n") %
                     (name, inst))
             if ui.print_exc():
                 return 1