fix: updating BaseAgent.clone() and LlmAgent.clone() to properly clone fields that are lists

src/google/adk/agents/base_agent.py

@@ -132,6 +132,26 @@ class BaseAgent(BaseModel):
       response and appended to event history as agent response.
   """
 
+  def _clone_list_fields(
+      self,
+      cloned_agent: BaseAgent,
+      update: Mapping[str, Any] | None,
+  ) -> None:
+    """Shallow copies fields that are lists and not provided in the update."""
+    if (update is None or 'before_agent_callback' not in update) and isinstance(
+        cloned_agent.before_agent_callback, list
+    ):
+      cloned_agent.before_agent_callback = (
+          cloned_agent.before_agent_callback.copy()
+      )
+
+    if (update is None or 'after_agent_callback' not in update) and isinstance(
+        cloned_agent.after_agent_callback, list
+    ):
+      cloned_agent.after_agent_callback = (
+          cloned_agent.after_agent_callback.copy()
+      )
+
   def clone(
       self: SelfAgent, update: Mapping[str, Any] | None = None
   ) -> SelfAgent:
@@ -165,6 +185,11 @@ def clone(
 
     cloned_agent = self.model_copy(update=update)
 
+    # If any field is stored as list and not provided in the update, need to
+    # shallow copy it for the cloned agent to avoid sharing the same list object
+    # with the original agent.
+    self._clone_list_fields(cloned_agent=cloned_agent, update=update)
+
     if update is None or 'sub_agents' not in update:
       # If `sub_agents` is not provided in the update, need to recursively clone
       # the sub-agents to avoid sharing the sub-agents with the original agent.

src/google/adk/agents/llm_agent.py

@@ -23,6 +23,7 @@
 from typing import Callable
 from typing import List
 from typing import Literal
+from typing import Mapping
 from typing import Optional
 from typing import Type
 from typing import Union
@@ -276,6 +277,43 @@ class LlmAgent(BaseAgent):
   """
   # Callbacks - End
 
+  @override
+  def _clone_list_fields(
+      self,
+      cloned_agent: LlmAgent,
+      update: Mapping[str, Any] | None,
+  ) -> None:
+    super()._clone_list_fields(cloned_agent=cloned_agent, update=update)
+
+    if (update is None or 'before_model_callback' not in update) and isinstance(
+        cloned_agent.before_model_callback, list
+    ):
+      cloned_agent.before_model_callback = (
+          cloned_agent.before_model_callback.copy()
+      )
+
+    if (update is None or 'after_model_callback' not in update) and isinstance(
+        cloned_agent.after_model_callback, list
+    ):
+      cloned_agent.after_model_callback = (
+          cloned_agent.after_model_callback.copy()
+      )
+
+    if (update is None or 'before_tool_callback' not in update) and isinstance(
+        cloned_agent.before_tool_callback, list
+    ):
+      cloned_agent.before_tool_callback = (
+          cloned_agent.before_tool_callback.copy()
+      )
+
+    if (update is None or 'after_tool_callback' not in update) and isinstance(
+        cloned_agent.after_tool_callback, list
+    ):
+      cloned_agent.after_tool_callback = cloned_agent.after_tool_callback.copy()
+
+    if update is None or 'tools' not in update:
+      cloned_agent.tools = cloned_agent.tools.copy()
+
   @override
   async def _run_async_impl(
       self, ctx: InvocationContext

tests/unittests/agents/test_agent_clone.py

@@ -374,6 +374,39 @@ def test_clone_with_sub_agents_update():
   assert original.sub_agents[1].name == "original_sub2"
 
 
+def test_clone_with_callbacks():
+  """Test cloning with callbacks in list format."""
+  before_agent_callback = [lambda *args, **kwargs: None]
+  after_agent_callback = [lambda *args, **kwargs: None]
+  before_model_callback = [lambda *args, **kwargs: None]
+  after_model_callback = [lambda *args, **kwargs: None]
+  before_tool_callback = [lambda *args, **kwargs: None]
+  after_tool_callback = [lambda *args, **kwargs: None]
+  tools = [lambda *args, **kwargs: None]
+
+  original = LlmAgent(
+      name="original_agent",
+      description="Original agent",
+      before_agent_callback=before_agent_callback,
+      after_agent_callback=after_agent_callback,
+      before_model_callback=before_model_callback,
+      after_model_callback=after_model_callback,
+      before_tool_callback=before_tool_callback,
+      after_tool_callback=after_tool_callback,
+      tools=tools,
+  )
+
+  cloned = original.clone()
+
+  assert id(original.before_agent_callback) != id(cloned.before_agent_callback)
+  assert id(original.after_agent_callback) != id(cloned.after_agent_callback)
+  assert id(original.before_model_callback) != id(cloned.before_model_callback)
+  assert id(original.after_model_callback) != id(cloned.after_model_callback)
+  assert id(original.before_tool_callback) != id(cloned.before_tool_callback)
+  assert id(original.after_tool_callback) != id(cloned.after_tool_callback)
+  assert id(original.tools) != id(cloned.tools)
+
+
 if __name__ == "__main__":
   # Run a specific test for debugging
   test_three_level_nested_agent()