First step in working with metaclasses in plugins, see #1090.

jedi/evaluate/context/klass.py

@@ -49,6 +49,7 @@ from jedi.evaluate.arguments import unpack_arglist, ValuesArguments
 from jedi.evaluate.base_context import ContextSet, iterator_to_context_set, \
     NO_CONTEXTS
 from jedi.evaluate.context.function import FunctionAndClassBase
+from jedi.plugins import plugin_manager
 
 
 def apply_py__get__(context, instance, class_context):
@@ -191,6 +192,11 @@ class ClassMixin(object):
 
     def get_filters(self, search_global=False, until_position=None,
                     origin_scope=None, is_instance=False):
+        metaclasses = self.get_metaclasses()
+        if metaclasses:
+            for f in self.get_metaclass_filters(metaclasses):
+                yield f
+
         if search_global:
             yield ParserTreeFilter(
                 self.evaluator,
@@ -247,12 +253,17 @@ class ClassContext(use_metaclass(CachedMetaClass, ClassMixin, FunctionAndClassBa
                     found.append(type_var)
         return found
 
-    @evaluator_method_cache(default=())
-    def py__bases__(self):
+    def _get_bases_arguments(self):
         arglist = self.tree_node.get_super_arglist()
         if arglist:
             from jedi.evaluate import arguments
-            args = arguments.TreeArguments(self.evaluator, self.parent_context, arglist)
+            return arguments.TreeArguments(self.evaluator, self.parent_context, arglist)
+        return None
+
+    @evaluator_method_cache(default=())
+    def py__bases__(self):
+        args = self._get_bases_arguments()
+        if args is not None:
             lst = [value for key, value in args.unpack() if key is None]
             if lst:
                 return lst
@@ -303,3 +314,24 @@ class ClassContext(use_metaclass(CachedMetaClass, ClassMixin, FunctionAndClassBa
     def get_signatures(self):
         init_funcs = self.py__getattribute__('__init__')
         return [sig.bind(self) for sig in init_funcs.get_signatures()]
+
+    @plugin_manager.decorate()
+    def get_metaclass_filters(self, metaclass):
+        debug.dbg('Unprocessed metaclass %s', metaclass)
+        return []
+
+    def get_metaclasses(self):
+        args = self._get_bases_arguments()
+        if args is not None:
+            m = [value for key, value in args.unpack() if key == 'metaclass']
+            metaclasses = ContextSet.from_sets(lazy_context.infer() for lazy_context in m)
+            metaclasses = ContextSet(m for m in metaclasses if m.is_class())
+            if metaclasses:
+                return metaclasses
+
+        for lazy_base in self.py__bases__():
+            for context in lazy_base.infer():
+                contexts = context.get_metaclasses()
+                if contexts:
+                    return contexts
+        return NO_CONTEXTS