extensions: print some debug info on import failure

This is handy if hgext.foo exists but has a bogus "import blah":
previously we just discarded the "No module named blah" error. Now at
least you can see it with --debug. Not perfect, but better than
nothing.

mercurial/extensions.py

@@ -1,353 +1,355 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.
 
 import imp, os
 import util, cmdutil, error
 from i18n import _, gettext
 
 _extensions = {}
 _order = []
 _ignore = ['hbisect', 'bookmarks', 'parentrevspec']
 
 def extensions():
     for name in _order:
         module = _extensions[name]
         if module:
             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.expandpath(path)
     if os.path.isdir(path):
         # module/__init__.py style
         d, f = os.path.split(path.rstrip('/'))
         fd, fpath, desc = imp.find_module(f, [d])
         return imp.load_module(module_name, fd, fpath, desc)
     else:
         return imp.load_source(module_name, path)
 
 def load(ui, name, path):
     # unused ui argument kept for backwards compatibility
     if name.startswith('hgext.') or name.startswith('hgext/'):
         shortname = name[6:]
     else:
         shortname = name
     if shortname in _ignore:
         return None
     if shortname in _extensions:
         return _extensions[shortname]
     _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
         mod = loadpath(path, 'hgext.%s' % name)
     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:
+        except ImportError, err:
+            ui.debug('could not import hgext.%s (%s): trying %s\n'
+                     % (name, err, name))
             mod = importh(name)
     _extensions[shortname] = mod
     _order.append(shortname)
     return mod
 
 def loadall(ui):
     result = ui.configitems("extensions")
     newindex = len(_order)
     for (name, path) in result:
         if path:
             if path[0] == '!':
                 continue
         try:
             load(ui, name, path)
         except KeyboardInterrupt:
             raise
         except Exception, inst:
             if path:
                 ui.warn(_("*** failed to import extension %s from %s: %s\n")
                         % (name, path, inst))
             else:
                 ui.warn(_("*** failed to import extension %s: %s\n")
                         % (name, inst))
             if ui.traceback():
                 return 1
 
     for name in _order[newindex:]:
         uisetup = getattr(_extensions[name], 'uisetup', None)
         if uisetup:
             uisetup(ui)
 
     for name in _order[newindex:]:
         extsetup = getattr(_extensions[name], 'extsetup', None)
         if extsetup:
             try:
                 extsetup(ui)
             except TypeError:
                 if extsetup.func_code.co_argcount != 0:
                     raise
                 extsetup() # old extsetup with no ui argument
 
 def wrapcommand(table, command, wrapper):
     '''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.
     '''
     assert util.safehasattr(wrapper, '__call__')
     aliases, entry = cmdutil.findcmd(command, table)
     for alias, e in table.iteritems():
         if e is entry:
             key = alias
             break
 
     origfn = entry[0]
     def wrap(*args, **kwargs):
         return util.checksignature(wrapper)(
             util.checksignature(origfn), *args, **kwargs)
 
     wrap.__doc__ = getattr(origfn, '__doc__')
     wrap.__module__ = getattr(origfn, '__module__')
 
     newentry = list(entry)
     newentry[0] = wrap
     table[key] = tuple(newentry)
     return entry
 
 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 util.safehasattr(wrapper, '__call__')
     def wrap(*args, **kwargs):
         return wrapper(origfn, *args, **kwargs)
 
     origfn = getattr(container, funcname)
     assert util.safehasattr(origfn, '__call__')
     setattr(container, funcname, wrap)
     return origfn
 
 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
         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
     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).splitlines()[0]
     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:
         pass
 
     paths = _disabledpaths()
     if not paths:
         return None
 
     exts = {}
     for name, path in paths.iteritems():
         doc = _disabledhelp(path)
         if doc:
             exts[name] = doc
 
     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:
         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, 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
         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)
 
     # 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'''
     exts = {}
     for ename, ext in extensions():
         doc = (gettext(ext.__doc__) or _('(no help text available)'))
         ename = ename.split('.')[-1]
         exts[ename] = doc.splitlines()[0].strip()
 
     return exts