fix: retry TypeAdapter creation without config if it fails

PiperOrigin-RevId: 927430716

Author: google-genai-bot

src/google/adk/tools/_function_tool_declarations.py

@@ -162,10 +162,21 @@ def _build_response_json_schema(
       return_annotation = type_args[0]
 
   try:
-    adapter = pydantic.TypeAdapter(
-        return_annotation,
-        config=pydantic.ConfigDict(arbitrary_types_allowed=True),
-    )
+    try:
+      adapter = pydantic.TypeAdapter(
+          return_annotation,
+          config=pydantic.ConfigDict(arbitrary_types_allowed=True),
+      )
+    except pydantic.PydanticUserError as e:
+      # If it failed, maybe it was because of the config argument (e.g. for dataclasses).
+      # Retry without config.
+      logging.debug(
+          'Failed to build schema with config, retrying without config for'
+          ' %s: %s',
+          func.__name__,
+          e,
+      )
+      adapter = pydantic.TypeAdapter(return_annotation)
     return adapter.json_schema()
   except Exception:
     logging.warning(

tests/unittests/tools/BUILD

@@ -44,3 +44,12 @@ pytest_test(
         "//third_party/py/pytest_asyncio",
     ],
 )
+
+pytest_test(
+    name = "test_function_tool_declarations",
+    srcs = ["test_function_tool_declarations.py"],
+    deps = [
+        "//third_party/py/absl/testing:parameterized",
+        "//third_party/py/google/adk",
+    ],
+)

tests/unittests/tools/test_function_tool_declarations.py

@@ -21,6 +21,7 @@
 from __future__ import annotations
 
 from collections.abc import Sequence
+import dataclasses
 from enum import Enum
 from typing import Any
 from typing import AsyncGenerator
@@ -76,6 +77,13 @@ class Window:
   height: int
 
 
+@dataclasses.dataclass
+class StandardReturnDataclass:
+  """A standard library dataclass for testing."""
+
+  status: str
+
+
 class TestBasicTypes(parameterized.TestCase):
   """Tests for basic Python types."""
 
@@ -618,6 +626,18 @@ def save_addresses(addresses: list[Address]) -> int:
         },
     )
 
+  def test_returns_standard_dataclass(self):
+    """Test function that returns a standard library dataclass."""
+
+    def get_status() -> StandardReturnDataclass:
+      return StandardReturnDataclass(status="ok")
+
+    decl = build_function_declaration_with_json_schema(get_status)
+
+    self.assertIsNotNone(decl.response_json_schema)
+    self.assertEqual(decl.response_json_schema["type"], "object")
+    self.assertIn("status", decl.response_json_schema["properties"])
+
 
 class TestSpecialCases(parameterized.TestCase):
   """Tests for special cases and edge cases."""