fix(pydantic v1): more robust ModelField.annotation check (#2163)

--------- Co-authored-by: Konnor Young <konnoryoung@ip-192-168-1-39.us-west-1.compute.internal> Co-authored-by: Robert Craigie <robert@craigie.dev>
openai · stainless-app · Apr 23, 2025 · Apr 18, 2025 · Apr 21, 2025 · Apr 21, 2025
commit 7351b12bc981f56632b92342d9ef26f6fb28d540
@@ -651,8 +651,8 @@ def _build_discriminated_union_meta(*, union: type, meta_annotations: tuple[Any,
                # Note: if one variant defines an alias then they all should
                discriminator_alias = field_info.alias

-                if field_info.annotation and is_literal_type(field_info.annotation):
-                    for entry in get_args(field_info.annotation):
+                if (annotation := getattr(field_info, 'annotation', None)) and is_literal_type(annotation):
+                    for entry in get_args(annotation):
                        if isinstance(entry, str):
                            mapping[entry] = variant