diff options
Diffstat (limited to 'Lib')
| -rw-r--r-- | Lib/dataclasses.py | 2 | ||||
| -rwxr-xr-x | Lib/test/test_dataclasses.py | 14 |
2 files changed, 13 insertions, 3 deletions
diff --git a/Lib/dataclasses.py b/Lib/dataclasses.py index 71d9896..325b822 100644 --- a/Lib/dataclasses.py +++ b/Lib/dataclasses.py @@ -241,7 +241,7 @@ class Field: self.hash = hash self.compare = compare self.metadata = (_EMPTY_METADATA - if metadata is None or len(metadata) == 0 else + if metadata is None else types.MappingProxyType(metadata)) self._field_type = None diff --git a/Lib/test/test_dataclasses.py b/Lib/test/test_dataclasses.py index ff6060c..9c83459 100755 --- a/Lib/test/test_dataclasses.py +++ b/Lib/test/test_dataclasses.py @@ -1737,23 +1737,33 @@ class TestCase(unittest.TestCase): i: int = field(metadata=0) # Make sure an empty dict works. + d = {} @dataclass class C: - i: int = field(metadata={}) + i: int = field(metadata=d) self.assertFalse(fields(C)[0].metadata) self.assertEqual(len(fields(C)[0].metadata), 0) + # Update should work (see bpo-35960). + d['foo'] = 1 + self.assertEqual(len(fields(C)[0].metadata), 1) + self.assertEqual(fields(C)[0].metadata['foo'], 1) with self.assertRaisesRegex(TypeError, 'does not support item assignment'): fields(C)[0].metadata['test'] = 3 # Make sure a non-empty dict works. + d = {'test': 10, 'bar': '42', 3: 'three'} @dataclass class C: - i: int = field(metadata={'test': 10, 'bar': '42', 3: 'three'}) + i: int = field(metadata=d) self.assertEqual(len(fields(C)[0].metadata), 3) self.assertEqual(fields(C)[0].metadata['test'], 10) self.assertEqual(fields(C)[0].metadata['bar'], '42') self.assertEqual(fields(C)[0].metadata[3], 'three') + # Update should work. + d['foo'] = 1 + self.assertEqual(len(fields(C)[0].metadata), 4) + self.assertEqual(fields(C)[0].metadata['foo'], 1) with self.assertRaises(KeyError): # Non-existent key. fields(C)[0].metadata['baz'] |