fix: Fix RemoteA2AAgent deepcopy errors

RemoteA2Agent's new _config attribute in v1.27.0 was not working with deepcopy() because it had Callable fields, causing agent engine deployment issues. This adds a custom deepcopy attribute that handles Callables by copying them by reference.

Co-authored-by: Kathy Wu <wukathy@google.com>
PiperOrigin-RevId: 893590078

Author: wukath

src/google/adk/a2a/agent/config.py

@@ -16,6 +16,7 @@
 
 from __future__ import annotations
 
+import copy
 from typing import Any
 from typing import Awaitable
 from typing import Callable
@@ -108,3 +109,16 @@ class A2aRemoteAgentConfig(BaseModel):
   )
 
   request_interceptors: Optional[list[RequestInterceptor]] = None
+
+  def __deepcopy__(self, memo):
+    cls = self.__class__
+    copied_values = {}
+    for k, v in self.__dict__.items():
+      if not k.startswith('_'):
+        if callable(v):
+          copied_values[k] = v
+        else:
+          copied_values[k] = copy.deepcopy(v, memo)
+    result = cls.model_construct(**copied_values)
+    memo[id(self)] = result
+    return result

tests/unittests/agents/test_remote_a2a_agent.py

@@ -12,6 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import copy
 import json
 from pathlib import Path
 import tempfile
@@ -36,6 +37,7 @@
 from a2a.types import TextPart
 from google.adk.a2a.agent import ParametersConfig
 from google.adk.a2a.agent import RequestInterceptor
+from google.adk.a2a.agent.config import A2aRemoteAgentConfig
 from google.adk.a2a.agent.utils import execute_after_request_interceptors
 from google.adk.a2a.agent.utils import execute_before_request_interceptors
 from google.adk.agents.invocation_context import InvocationContext
@@ -2866,3 +2868,28 @@ async def test_execute_after_request_interceptors_no_after_request(
     )
 
     assert result is event
+
+
+class TestRemoteA2aAgentDeepcopy:
+  """Test deepcopy functionality for RemoteA2aAgent and its config."""
+
+  def test_deepcopy_config(self):
+    """Test that A2aRemoteAgentConfig can be deepcopied with interceptors."""
+    config = A2aRemoteAgentConfig()
+    mock_interceptor = Mock()
+    config.request_interceptors = [mock_interceptor]
+
+    copied_config = copy.deepcopy(config)
+    assert copied_config is not None
+
+    # Verify that functions are shared (by reference)
+    assert copied_config.a2a_message_converter is config.a2a_message_converter
+
+    # Verify that request_interceptors list was copied
+    assert copied_config.request_interceptors is not None
+    assert len(copied_config.request_interceptors) == 1
+    # Standard objects inside lists should be deepcopied (new instances)
+    assert (
+        copied_config.request_interceptors[0]
+        is not config.request_interceptors[0]
+    )