A transform for the builtin `dataclasses` module was added.

This should address various `dataclasses` issues that were surfaced
even more after the release of pylint 2.4.0.
In the previous versions of `astroid`, annotated assign nodes were
allowed to be retrieved via `getattr()` but that no longer happens
with the latest `astroid` release, as those attribute are not actual
attributes, but rather virtual ones, thus an operation such as `getattr()`
does not make sense for them.

1 files changed, 33 insertions, 0 deletions

diff --git a/astroid/tests/unittest_brain.py b/astroid/tests/unittest_brain.py
index a045b194..9b29a280 100644
--- a/astroid/tests/unittest_brain.py
+++ b/astroid/tests/unittest_brain.py
@@ -1927,5 +1927,38 @@ def test_crypt_brain():
         assert attr in module
 
 
+@pytest.mark.skipif(sys.version_info < (3, 7), reason="Dataclasses were added in 3.7")
+def test_dataclasses():
+    code = """
+    import dataclasses
+    from dataclasses import dataclass
+
+    @dataclass
+    class InventoryItem:
+        name: str
+        quantity_on_hand: int = 0
+
+    @dataclasses.dataclass
+    class Other:
+        name: str
+    """
+
+    module = astroid.parse(code)
+    first = module["InventoryItem"]
+    second = module["Other"]
+
+    name = first.getattr("name")
+    assert len(name) == 1
+    assert isinstance(name[0], astroid.Unknown)
+
+    quantity_on_hand = first.getattr("quantity_on_hand")
+    assert len(quantity_on_hand) == 1
+    assert isinstance(quantity_on_hand[0], astroid.Unknown)
+
+    name = second.getattr("name")
+    assert len(name) == 1
+    assert isinstance(name[0], astroid.Unknown)
+
+
 if __name__ == "__main__":
     unittest.main()