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

jedi/evaluate/compiled/context.py

@@ -264,6 +264,9 @@ class CompiledObject(Context):
     def negate(self):
         return create_from_access_path(self.evaluator, self.access_handle.negate())
 
+    def get_metaclasses(self):
+        return NO_CONTEXTS
+
 
 class CompiledName(AbstractNameDefinition):
     def __init__(self, evaluator, parent_context, name):

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

jedi/plugins/stdlib.py

@@ -13,6 +13,7 @@ import parso
 
 from jedi._compatibility import force_unicode
 from jedi import debug
+from jedi.evaluate.utils import safe_property
 from jedi.evaluate.helpers import get_str_or_none
 from jedi.evaluate.arguments import ValuesArguments, \
     repack_with_argument_clinic, AbstractArguments, TreeArgumentsWrapper
@@ -26,8 +27,10 @@ from jedi.evaluate.context import ClassContext, ModuleContext, \
 from jedi.evaluate.context import iterable
 from jedi.evaluate.lazy_context import LazyTreeContext, LazyKnownContext, \
     LazyKnownContexts
+from jedi.evaluate.names import ContextName
 from jedi.evaluate.syntax_tree import is_string
-from jedi.evaluate.filters import AttributeOverwrite, publish_method
+from jedi.evaluate.filters import AttributeOverwrite, publish_method, \
+    ParserTreeFilter, DictFilter
 
 
 # Copied from Python 3.6's stdlib.
@@ -602,3 +605,41 @@ _implemented = {
         'dataclass': lambda obj, arguments: NO_CONTEXTS,
     },
 }
+
+
+def get_metaclass_filters(func):
+    def wrapper(cls, metaclasses):
+        for metaclass in metaclasses:
+            if metaclass.py__name__() == 'EnumMeta' \
+                    and metaclass.get_root_context().py__name__() == 'enum':
+                print('cont', cls)
+                filter_ = ParserTreeFilter(cls.evaluator, context=cls)
+                return [DictFilter({
+                    name.string_name: EnumInstance(cls, name).name for name in filter_.values()
+                })]
+        return func(cls, metaclasses)
+    return wrapper
+
+
+class EnumInstance(LazyContextWrapper):
+    def __init__(self, cls, name):
+        self.evaluator = cls.evaluator
+        self._cls = cls  # Corresponds to super().__self__
+        self._name = name
+        self.tree_node = self._name.tree_name
+
+    @safe_property
+    def name(self):
+        return ContextName(self, self._name.tree_name)
+
+    def _get_wrapped_context(self):
+        obj, = self._cls.execute_evaluated()
+        return obj
+
+    def get_filters(self, search_global=False, position=None, origin_scope=None):
+        yield DictFilter(dict(
+            name=self._name.string_name,
+            value=self._name,
+        ))
+        for f in self._get_wrapped_context().get_filters():
+            yield f

test/completion/stdlib.py

@@ -290,3 +290,31 @@ class Test(metaclass=Meta):
         result = super(Test, self).test_function()
         #? []
         result.
+
+# -----------------
+# Enum
+# -----------------
+
+# python >= 3.4
+import enum
+
+class X(enum.Enum):
+    attr_x = 3
+    attr_y = 2.0
+
+#? ['mro']
+X.mro
+#? ['attr_x', 'attr_y']
+X.attr_
+#? str()
+X.attr_x.name
+#? int()
+X.attr_x.value
+#? str()
+X.attr_y.name
+#? float()
+X.attr_y.value
+#? str()
+X().name
+#? float()
+X().attr_x.attr_y.value

test/test_evaluate/test_imports.py

@@ -472,6 +472,6 @@ def test_relative_import_star(Script):
     from . import *
     furl.c
     """
-    script = jedi.Script(source,3,len("furl.c"), 'export.py')
+    script = jedi.Script(source, 3, len("furl.c"), 'export.py')
 
     assert script.completions()