fix: Remove deprecated _UnionGenericAlias to support Python 3.14+

Replace usage of private typing._UnionGenericAlias (deprecated in Python 3.14, removed in 3.17) with tuple-based isinstance checks using type(Union[int, str]). This maintains compatibility with both old-style Union[T1, T2] and new-style T1 | T2 syntax while avoiding deprecation warnings.

Author: miettal

google/genai/_automatic_function_calling_util.py

@@ -26,9 +26,9 @@
 
 
 if sys.version_info >= (3, 10):
-  VersionedUnionType = builtin_types.UnionType
+  VersionedUnionType = (builtin_types.UnionType, type(Union[int, str]))
 else:
-  VersionedUnionType = typing._UnionGenericAlias  # type: ignore[attr-defined]
+  VersionedUnionType = (type(Union[int, str]),)
 
 
 __all__ = [

google/genai/_transformers.py

@@ -42,11 +42,11 @@
 logger = logging.getLogger('google_genai._transformers')
 
 if sys.version_info >= (3, 10):
-  VersionedUnionType = builtin_types.UnionType
+  VersionedUnionType = (builtin_types.UnionType, type(Union[int, str]))
   _UNION_TYPES = (typing.Union, builtin_types.UnionType)
   from typing import TypeGuard
 else:
-  VersionedUnionType = typing._UnionGenericAlias  # type: ignore[attr-defined]
+  VersionedUnionType = (type(Union[int, str]),)
   _UNION_TYPES = (typing.Union,)
   from typing_extensions import TypeGuard
 

google/genai/types.py

@@ -25,7 +25,7 @@
 import sys
 import types as builtin_types
 import typing
-from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Union, _UnionGenericAlias  # type: ignore
+from typing import Any, Callable, Dict, List, Literal, Optional, Sequence, Union
 import pydantic
 from pydantic import ConfigDict, Field, PrivateAttr, model_validator
 from typing_extensions import Self, TypedDict
@@ -40,11 +40,11 @@
 
 if sys.version_info >= (3, 10):
   # Supports both Union[t1, t2] and t1 | t2
-  VersionedUnionType = Union[builtin_types.UnionType, _UnionGenericAlias]
+  VersionedUnionType = (builtin_types.UnionType, type(Union[int, str]))
   _UNION_TYPES = (typing.Union, builtin_types.UnionType)
 else:
   # Supports only Union[t1, t2]
-  VersionedUnionType = _UnionGenericAlias
+  VersionedUnionType = (type(Union[int, str]),)
   _UNION_TYPES = (typing.Union,)
 
 _is_pillow_image_imported = False