Adding required flags to non-default arguments in hf_argparser (#10688)

* Adding required flags to non-default arguments.
Signed-off-by: Adam Pocock <adam.pocock@oracle.com>

* make style fix.

* Update src/transformers/hf_argparser.py
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>

src/transformers/hf_argparser.py

@@ -99,6 +99,8 @@ class HfArgumentParser(ArgumentParser):
                 kwargs["type"] = type(kwargs["choices"][0])
                 if field.default is not dataclasses.MISSING:
                     kwargs["default"] = field.default
+                else:
+                    kwargs["required"] = True
             elif field.type is bool or field.type == Optional[bool]:
                 if field.default is True:
                     self.add_argument(f"--no_{field.name}", action="store_false", dest=field.name, **kwargs)
@@ -124,6 +126,8 @@ class HfArgumentParser(ArgumentParser):
                 ), "{} cannot be a List of mixed types".format(field.name)
                 if field.default_factory is not dataclasses.MISSING:
                     kwargs["default"] = field.default_factory()
+                elif field.default is dataclasses.MISSING:
+                    kwargs["required"] = True
             else:
                 kwargs["type"] = field.type
                 if field.default is not dataclasses.MISSING:

tests/test_hf_argparser.py

@@ -78,6 +78,16 @@ class ListExample:
     foo_float: List[float] = list_field(default=[0.1, 0.2, 0.3])
 
 
+@dataclass
+class RequiredExample:
+    required_list: List[int] = field()
+    required_str: str = field()
+    required_enum: BasicEnum = field()
+
+    def __post_init__(self):
+        self.required_enum = BasicEnum(self.required_enum)
+
+
 class HfArgumentParserTest(unittest.TestCase):
     def argparsersEqual(self, a: argparse.ArgumentParser, b: argparse.ArgumentParser) -> bool:
         """
@@ -186,6 +196,15 @@ class HfArgumentParserTest(unittest.TestCase):
         args = parser.parse_args("--foo 12 --bar 3.14 --baz 42 --ces a b c --des 1 2 3".split())
         self.assertEqual(args, Namespace(foo=12, bar=3.14, baz="42", ces=["a", "b", "c"], des=[1, 2, 3]))
 
+    def test_with_required(self):
+        parser = HfArgumentParser(RequiredExample)
+
+        expected = argparse.ArgumentParser()
+        expected.add_argument("--required_list", nargs="+", type=int, required=True)
+        expected.add_argument("--required_str", type=str, required=True)
+        expected.add_argument("--required_enum", type=str, choices=["titi", "toto"], required=True)
+        self.argparsersEqual(parser, expected)
+
     def test_parse_dict(self):
         parser = HfArgumentParser(BasicExample)