fix: Handle generic types in UnsupportedTypeError

This commit fixes a test failure caused by an `AttributeError` when handling generic types from the `typing` module in the `UnsupportedTypeError` class.

The `__init__` method of `UnsupportedTypeError` has been updated to check if a type is a generic from the `typing` module and, if so, convert it to a string directly to get the full type representation (e.g., `list[str]`). This ensures that the error message is generated correctly without raising an `AttributeError`.

A new unit test has also been added to `tests/unit/functions/test_function_typing.py` to verify the fix.

Author: google-labs-jules[bot]

bigframes/functions/function_typing.py

@@ -65,10 +65,16 @@ def __init__(self, type_, supported_types):
         if isinstance(supported_types, dict):
             types_to_format = supported_types.keys()
 
-        supported_types_str = ", ".join(sorted([t.__name__ for t in types_to_format]))
+        supported_types_str = ", ".join(
+            sorted([getattr(t, "__name__", str(t)) for t in types_to_format])
+        )
+        if get_origin(type_) is not None:
+            type_str = str(type_)
+        else:
+            type_str = getattr(type_, "__name__", str(type_))
 
         super().__init__(
-            f"'{type_.__name__}' must be one of the supported types ({supported_types_str}) "
+            f"'{type_str}' must be one of the supported types ({supported_types_str}) "
             "or a list of one of those types."
         )
 

tests/unit/functions/test_function_typing.py

@@ -55,3 +55,14 @@ def test_sdk_type_from_python_type_raises_unsupported_type_error():
         function_typing.sdk_type_from_python_type(unsupported_type)
     assert "datetime" in str(excinfo.value)
     assert "bool, bytes, float, int, str" in str(excinfo.value)
+
+
+def test_sdk_type_from_python_type_with_generic_type_raises_unsupported_type_error():
+    # Arrange
+    unsupported_type = list[str]
+
+    # Act & Assert
+    with pytest.raises(function_typing.UnsupportedTypeError) as excinfo:
+        function_typing.sdk_type_from_python_type(unsupported_type)
+    assert "list[str]" in str(excinfo.value)
+    assert "bool, bytes, float, int, str" in str(excinfo.value)