Fix the weird py__path__ behavior

jedi/inference/compiled/access.py

@@ -273,7 +273,13 @@ class DirectObjectAccess(object):
         return [self._create_access_path(base) for base in self._obj.__bases__]
 
     def py__path__(self):
-        return self._obj.__path__
+        paths = getattr(self._obj, '__path__', None)
+        # Avoid some weird hacks that would just fail, because they cannot be
+        # used by pickle.
+        if not isinstance(paths, list) \
+                or not all(isinstance(p, (bytes, unicode)) for p in paths):
+            return None
+        return paths
 
     @_force_unicode_decorator
     def get_repr(self):

jedi/inference/compiled/mixed.py

@@ -277,7 +277,7 @@ def _create(inference_state, access_handle, parent_context, *args):
                 file_io=file_io,
                 string_names=string_names,
                 code_lines=code_lines,
-                is_package=hasattr(compiled_object, 'py__path__'),
+                is_package=compiled_object.is_package,
             ).as_context()
             if name is not None:
                 inference_state.module_cache.add(string_names, ValueSet([module_context]))

jedi/inference/compiled/value.py

@@ -83,9 +83,14 @@ class CompiledObject(Value):
             for access in self.access_handle.py__bases__()
         )
 
-    @CheckAttribute()
     def py__path__(self):
-        return map(cast_path, self.access_handle.py__path__())
+        paths = self.access_handle.py__path__()
+        if paths is None:
+            return None
+        return map(cast_path, paths)
+
+    def is_package(self):
+        return self.py__path__() is not None
 
     @property
     def string_names(self):