diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index 2f0e5ff0b6e039..391f32e11d52a1 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -210,7 +210,12 @@ def __init__(self, type): self.type = type def __repr__(self): - return f'dataclasses.InitVar[{self.type.__name__}]' + if isinstance(self.type, type): + type_name = self.type.__name__ + else: + # typing objects, e.g. List[int] + type_name = repr(self.type) + return f'dataclasses.InitVar[{type_name}]' # Instances of Field are only ever created from within this module, diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index 0885c9798fe68a..b018133cf23025 100755 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -1102,6 +1102,8 @@ def test_init_var_preserve_type(self): # Make sure the repr is correct. self.assertEqual(repr(InitVar[int]), 'dataclasses.InitVar[int]') + self.assertEqual(repr(InitVar[List[int]]), + 'dataclasses.InitVar[typing.List[int]]') def test_init_var_inheritance(self): # Note that this deliberately tests that a dataclass need not diff --git a/Misc/NEWS.d/next/Library/2019-10-10-16-53-00.bpo-38431.d5wzNp.rst b/Misc/NEWS.d/next/Library/2019-10-10-16-53-00.bpo-38431.d5wzNp.rst new file mode 100644 index 00000000000000..c2f860d804c13a --- /dev/null +++ b/Misc/NEWS.d/next/Library/2019-10-10-16-53-00.bpo-38431.d5wzNp.rst @@ -0,0 +1 @@ +Fix ``__repr__`` method for :class:`dataclasses.InitVar` to support typing objects, patch by Samuel Colvin.