Better dummies (#15148)

* Better dummies

* See if this fixes the issue

* Fix quality

* Style

* Add doc for DummyObject

utils/check_dummies.py

@@ -33,46 +33,15 @@ DUMMY_CONSTANT = """
 {0} = None
 """
 
-DUMMY_PRETRAINED_CLASS = """
-class {0}:
-    def __init__(self, *args, **kwargs):
-        requires_backends(self, {1})
-
-    @classmethod
-    def from_pretrained(cls, *args, **kwargs):
-        requires_backends(cls, {1})
-"""
-
-PT_DUMMY_PRETRAINED_CLASS = (
-    DUMMY_PRETRAINED_CLASS
-    + """
-    def forward(self, *args, **kwargs):
-        requires_backends(self, {1})
-"""
-)
-
-TF_DUMMY_PRETRAINED_CLASS = (
-    DUMMY_PRETRAINED_CLASS
-    + """
-    def call(self, *args, **kwargs):
-        requires_backends(self, {1})
-"""
-)
-
-FLAX_DUMMY_PRETRAINED_CLASS = (
-    DUMMY_PRETRAINED_CLASS
-    + """
-    def __call__(self, *args, **kwargs):
-        requires_backends(self, {1})
-"""
-)
-
 DUMMY_CLASS = """
-class {0}:
+class {0}(metaclass=DummyObject):
+    _backends = {1}
+
     def __init__(self, *args, **kwargs):
         requires_backends(self, {1})
 """
 
+
 DUMMY_FUNCTION = """
 def {0}(*args, **kwargs):
     requires_backends({0}, {1})
@@ -126,45 +95,12 @@ def read_init():
 
 def create_dummy_object(name, backend_name):
     """Create the code for the dummy object corresponding to `name`."""
-    _models = [
-        "ForCausalLM",
-        "ForConditionalGeneration",
-        "ForMaskedLM",
-        "ForMultipleChoice",
-        "ForNextSentencePrediction",
-        "ForObjectDetection",
-        "ForQuestionAnswering",
-        "ForSegmentation",
-        "ForSequenceClassification",
-        "ForTokenClassification",
-        "Model",
-    ]
-    _pretrained = ["Config", "Tokenizer", "Processor"]
     if name.isupper():
         return DUMMY_CONSTANT.format(name)
     elif name.islower():
         return DUMMY_FUNCTION.format(name, backend_name)
     else:
-        is_model = False
-        for part in _models:
-            if part in name:
-                is_model = True
-                break
-        if is_model:
-            if name.startswith("TF"):
-                return TF_DUMMY_PRETRAINED_CLASS.format(name, backend_name)
-            if name.startswith("Flax"):
-                return FLAX_DUMMY_PRETRAINED_CLASS.format(name, backend_name)
-            return PT_DUMMY_PRETRAINED_CLASS.format(name, backend_name)
-        is_pretrained = False
-        for part in _pretrained:
-            if part in name:
-                is_pretrained = True
-                break
-        if is_pretrained:
-            return DUMMY_PRETRAINED_CLASS.format(name, backend_name)
-        else:
-            return DUMMY_CLASS.format(name, backend_name)
+        return DUMMY_CLASS.format(name, backend_name)
 
 
 def create_dummy_files():
@@ -176,7 +112,8 @@ def create_dummy_files():
     for backend, objects in backend_specific_objects.items():
         backend_name = "[" + ", ".join(f'"{b}"' for b in backend.split("_and_")) + "]"
         dummy_file = "# This file is autogenerated by the command `make fix-copies`, do not edit.\n"
-        dummy_file += "from ..file_utils import requires_backends\n\n"
+        dummy_file += "# flake8: noqa\n"
+        dummy_file += "from ..file_utils import DummyObject, requires_backends\n\n"
         dummy_file += "\n".join([create_dummy_object(o, backend_name) for o in objects])
         dummy_files[backend] = dummy_file