cfg update

Summary: Pull Request resolved: fairinternal/detectron2#516

Reviewed By: alexander-kirillov

Differential Revision: D27017312

Pulled By: ppwwyyxx

fbshipit-source-id: 36995a9a5ccf3c98283e44db6ba34094b26c9f2c

detectron2/config/instantiate.py

@@ -45,7 +45,10 @@ def instantiate(cfg):
     """
     from omegaconf import ListConfig
 
-    if isinstance(cfg, (list, tuple, ListConfig)):
+    if isinstance(cfg, ListConfig):
+        lst = [instantiate(x) for x in cfg]
+        return ListConfig(lst, flags={"allow_objects": True})
+    if isinstance(cfg, list):
         # Specialize for list, because many classes take
         # list[objects] as arguments, such as ResNet, DatasetMapper
         return [instantiate(x) for x in cfg]