demandimport: fix an obscure corner-case.

Python's __import__() function has 'level' as the fourth argument, not the
third. The code path in question probably never worked.

(This was seen trying to run Mercurial in PyPy. Fixing this made it
die somewhere else...)

mercurial/demandimport.py

@@ -1,160 +1,160 b''
 # demandimport.py - global demand-loading of modules for Mercurial
 #
 # Copyright 2006, 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.
 
 '''
 demandimport - automatic demandloading of modules
 
 To enable this module, do:
 
   import demandimport; demandimport.enable()
 
 Imports of the following forms will be demand-loaded:
 
   import a, b.c
   import a.b as c
   from a import b,c # a will be loaded immediately
 
 These imports will not be delayed:
 
   from a import *
   b = __import__(a)
 '''
 
 import __builtin__
 _origimport = __import__
 
 class _demandmod(object):
     """module demand-loader and proxy"""
     def __init__(self, name, globals, locals, level):
         if '.' in name:
             head, rest = name.split('.', 1)
             after = [rest]
         else:
             head = name
             after = []
         object.__setattr__(self, "_data", (head, globals, locals, after, level))
         object.__setattr__(self, "_module", None)
     def _extend(self, name):
         """add to the list of submodules to load"""
         self._data[3].append(name)
     def _load(self):
         if not self._module:
             head, globals, locals, after, level = self._data
             if level is not None:
-                mod = _origimport(head, globals, locals, level)
+                mod = _origimport(head, globals, locals, level=level)
             else:
                 mod = _origimport(head, globals, locals)
             # load submodules
             def subload(mod, p):
                 h, t = p, None
                 if '.' in p:
                     h, t = p.split('.', 1)
                 if not hasattr(mod, h):
                     # TODO: should we adjust the level here?
                     submod = _demandmod(p, mod.__dict__, mod.__dict__,
                                         level=level)
                     setattr(mod, h, submod)
                 elif t:
                     subload(getattr(mod, h), t)
 
             for x in after:
                 subload(mod, x)
 
             # are we in the locals dictionary still?
             if locals and locals.get(head) == self:
                 locals[head] = mod
             object.__setattr__(self, "_module", mod)
 
     def __repr__(self):
         if self._module:
             return "<proxied module '%s'>" % self._data[0]
         return "<unloaded module '%s'>" % self._data[0]
     def __call__(self, *args, **kwargs):
         raise TypeError("%s object is not callable" % repr(self))
     def __getattribute__(self, attr):
         if attr in ('_data', '_extend', '_load', '_module'):
             return object.__getattribute__(self, attr)
         self._load()
         return getattr(self._module, attr)
     def __setattr__(self, attr, val):
         self._load()
         setattr(self._module, attr, val)
 
 def _demandimport(name, globals=None, locals=None, fromlist=None, level=None):
     if not locals or name in ignore or fromlist == ('*',):
         # these cases we can't really delay
         if level is None:
             return _origimport(name, globals, locals, fromlist)
         else:
             return _origimport(name, globals, locals, fromlist, level)
     elif not fromlist:
         # import a [as b]
         if '.' in name: # a.b
             base, rest = name.split('.', 1)
             # email.__init__ loading email.mime
             if globals and globals.get('__name__', None) == base:
                 if level is not None:
                     return _origimport(name, globals, locals, fromlist, level)
                 else:
                     return _origimport(name, globals, locals, fromlist)
             # if a is already demand-loaded, add b to its submodule list
             if base in locals:
                 if isinstance(locals[base], _demandmod):
                     locals[base]._extend(rest)
                 return locals[base]
         return _demandmod(name, globals, locals, level=level)
     else:
         # from a import b,c,d
         if level is not None:
             mod = _origimport(name, globals, locals, level=level)
         else:
             mod = _origimport(name, globals, locals)
         # recurse down the module chain
         for comp in name.split('.')[1:]:
             if not hasattr(mod, comp):
                 # TODO: should we adjust the level here?
                 submod = _demandmod(comp, mod.__dict__, mod.__dict__,
                                     level=level)
                 setattr(mod, comp, submod)
             mod = getattr(mod, comp)
         for x in fromlist:
             # set requested submodules for demand load
             if not(hasattr(mod, x)):
                 # TODO: should we adjust the level here?
                 submod = _demandmod(x, mod.__dict__, locals, level=level)
                 setattr(mod, x, submod)
         return mod
 
 ignore = [
     '_hashlib',
     '_xmlplus',
     'fcntl',
     'win32com.gen_py',
     '_winreg', # 2.7 mimetypes needs immediate ImportError
     'pythoncom',
     # imported by tarfile, not available under Windows
     'pwd',
     'grp',
     # imported by profile, itself imported by hotshot.stats,
     # not available under Windows
     'resource',
     # this trips up many extension authors
     'gtk',
     # setuptools' pkg_resources.py expects "from __main__ import x" to
     # raise ImportError if x not defined
     '__main__',
     '_ssl', # conditional imports in the stdlib, issue1964
     ]
 
 def enable():
     "enable global demand-loading of modules"
     __builtin__.__import__ = _demandimport
 
 def disable():
     "disable global demand-loading of modules"
     __builtin__.__import__ = _origimport