update from upstream

1 files changed, 19 insertions, 7 deletions

diff --git a/devscripts/lazy_load_template.py b/devscripts/lazy_load_template.py
index c4e5fc1f4..da89e070d 100644
--- a/devscripts/lazy_load_template.py
+++ b/devscripts/lazy_load_template.py
@@ -1,19 +1,31 @@
 # coding: utf-8
-from __future__ import unicode_literals
-
 import re
 
+from ..utils import bug_reports_message, write_string
+
+
+class LazyLoadMetaClass(type):
+    def __getattr__(cls, name):
+        if '_real_class' not in cls.__dict__:
+            write_string(
+                f'WARNING: Falling back to normal extractor since lazy extractor '
+                f'{cls.__name__} does not have attribute {name}{bug_reports_message()}')
+        return getattr(cls._get_real_class(), name)
+
 
-class LazyLoadExtractor(object):
+class LazyLoadExtractor(metaclass=LazyLoadMetaClass):
     _module = None
+    _WORKING = True
 
     @classmethod
-    def ie_key(cls):
-        return cls.__name__[:-2]
+    def _get_real_class(cls):
+        if '_real_class' not in cls.__dict__:
+            mod = __import__(cls._module, fromlist=(cls.__name__,))
+            cls._real_class = getattr(mod, cls.__name__)
+        return cls._real_class
 
     def __new__(cls, *args, **kwargs):
-        mod = __import__(cls._module, fromlist=(cls.__name__,))
-        real_cls = getattr(mod, cls.__name__)
+        real_cls = cls._get_real_class()
         instance = real_cls.__new__(real_cls)
         instance.__init__(*args, **kwargs)
         return instance