fix: optional union types being marked as required

Author: mak626

graphene_pydantic/converters.py

@@ -8,6 +8,7 @@
 import typing as T
 import uuid
 from types import UnionType
+from typing import get_origin
 
 import graphene
 from graphene import (
@@ -113,9 +114,14 @@ def convert_pydantic_field(
     to the generated Graphene data model type.
     """
     declared_type = getattr(field, "annotation", None)
+
     # Convert Python 11 UnionType to T.Union
-    if isinstance(declared_type, UnionType):
+    is_union_type = (
+        get_origin(declared_type) is T.Union or get_origin(declared_type) is UnionType
+    )
+    if is_union_type:
         declared_type = T.Union[declared_type.__args__]
+
     field_kwargs.setdefault(
         "type" if GRAPHENE2 else "type_",
         convert_pydantic_type(
@@ -128,6 +134,7 @@ def convert_pydantic_field(
         or (
             type(field.default) is not PydanticUndefined
             and getattr(declared_type, "_name", "") != "Optional"
+            and not is_union_type
         ),
     )
     field_kwargs.setdefault(

tests/test_converters.py

@@ -4,6 +4,7 @@
 import sys
 import typing as T
 import uuid
+from typing import Optional
 
 import graphene
 import graphene.types
@@ -70,10 +71,26 @@ def test_builtin_scalars(input, expected):
     assert field.default_value == input[1]
 
 
-def test_union():
+def test_union_optional():
     field = _convert_field_from_spec("attr", (T.Union[int, float, str], 5.0))
-    assert issubclass(field.type.of_type, graphene.Union)
+    assert issubclass(field.type, graphene.Union)
     assert field.default_value == 5.0
+    assert field.type.__name__.startswith("UnionOf")
+
+
+@pytest.mark.parametrize(
+    "input",
+    [
+        (T.Union[int, float, str], ...),
+        (T.Union[int, float, str, None], ...),
+        (Optional[T.Union[int, float, str]], ...),
+        (Optional[T.Union[int, float, None]], ...),
+    ],
+)
+def test_union(input):
+    field = _convert_field_from_spec("attr", input)
+    assert isinstance(field.type, graphene.NonNull)
+    assert field.default_value == None
     assert field.type.of_type.__name__.startswith("UnionOf")
 
 
@@ -95,6 +112,27 @@ def test_literal_singleton():
         assert field.default_value == "literal1"
         assert field.type.of_type == graphene.String
 
+    def test_union_pipe_optional():
+        field = _convert_field_from_spec("attr", (int | float | str, 5.0))
+        assert issubclass(field.type, graphene.Union)
+        assert field.default_value == 5.0
+        assert field.type.__name__.startswith("UnionOf")
+
+    @pytest.mark.parametrize(
+        "input",
+        [
+            (int | float | str, ...),
+            (int | float | str | None, ...),
+            (Optional[int | float | str], ...),
+            (Optional[int | float | None], ...),
+        ],
+    )
+    def test_union_pipe(input):
+        field = _convert_field_from_spec("attr", input)
+        assert isinstance(field.type, graphene.NonNull)
+        assert field.default_value == None
+        assert field.type.of_type.__name__.startswith("UnionOf")
+
 
 def test_mapping():
     with pytest.raises(ConversionError) as exc: