refactor(agents): Revert "Support ADK 2.0 workflow execution in SequentialAgent"

Change-Id: I1ed948f8b79a707ea505c297457dc56e2d155e44

Author: xuanyang15

src/google/adk/agents/sequential_agent.py

@@ -30,7 +30,6 @@
 from .base_agent import BaseAgent
 from .base_agent import BaseAgentState
 from .base_agent_config import BaseAgentConfig
-from .context import Context
 from .invocation_context import InvocationContext
 from .llm_agent import LlmAgent
 from .sequential_agent_config import SequentialAgentConfig
@@ -52,9 +51,6 @@ class SequentialAgent(BaseAgent):
   config_type: ClassVar[Type[BaseAgentConfig]] = SequentialAgentConfig
   """The config type for this agent."""
 
-  rerun_on_resume: bool = True
-  """SequentialAgent needs to rerun on resume to drive its sub-agents."""
-
   @override
   async def _run_async_impl(
       self, ctx: InvocationContext
@@ -161,23 +157,3 @@ def task_completed():
       async with Aclosing(sub_agent.run_live(ctx)) as agen:
         async for event in agen:
           yield event
-
-  @override
-  async def _run_impl(
-      self,
-      *,
-      ctx: Context,
-      node_input: Any,
-  ) -> AsyncGenerator[Any, None]:
-    """Runs the sequential agent as a node."""
-    if not self.sub_agents:
-      return
-
-    output = None
-    for i, sub_agent in enumerate(self.sub_agents):
-      # Pass initial input to the first agent, and None to the rest to avoid
-      # duplicate messages in session for agents that rely on session history.
-      inp = node_input if i == 0 else None
-      output = await ctx.run_node(sub_agent, node_input=inp)
-
-    yield output

tests/unittests/agents/test_sequential_agent.py

@@ -17,14 +17,12 @@
 from typing import AsyncGenerator
 
 from google.adk.agents.base_agent import BaseAgent
-from google.adk.agents.context import Context
 from google.adk.agents.invocation_context import InvocationContext
 from google.adk.agents.sequential_agent import SequentialAgent
 from google.adk.agents.sequential_agent import SequentialAgentState
 from google.adk.apps import ResumabilityConfig
 from google.adk.events.event import Event
 from google.adk.sessions.in_memory_session_service import InMemorySessionService
-from google.adk.sessions.session import Session
 from google.genai import types
 import pytest
 from typing_extensions import override
@@ -203,40 +201,3 @@ async def test_run_live(request: pytest.FixtureRequest):
   assert events[1].author == agent_2.name
   assert events[0].content.parts[0].text == f'Hello, live {agent_1.name}!'
   assert events[1].content.parts[0].text == f'Hello, live {agent_2.name}!'
-
-
-@pytest.mark.asyncio
-async def test_sequential_agent_as_node():
-  """Tests that SequentialAgent runs as a node and uses ctx.run_node."""
-  sub_agent1 = _TestingAgent(name="sub1")
-  sub_agent2 = _TestingAgent(name="sub2")
-  seq_agent = SequentialAgent(name="seq_agent", sub_agents=[sub_agent1, sub_agent2])
-
-  # Setup minimal context
-  session = Session(app_name="test", user_id="user", id="session")
-  session_service = InMemorySessionService()
-  ic = InvocationContext(
-      invocation_id="inv",
-      session=session,
-      session_service=session_service,
-  )
-  ctx = Context(ic, node_path="wf")
-
-  # Mock run_node
-  run_node_calls = []
-  async def mock_run_node(node, node_input=None, **kwargs):
-    run_node_calls.append((node, node_input))
-    return f"output_from_{node.name}"
-
-  ctx.run_node = mock_run_node
-
-  events = []
-  async for event in seq_agent.run(ctx=ctx, node_input="initial_input"):
-    events.append(event)
-
-  assert len(run_node_calls) == 2
-  assert run_node_calls[0] == (sub_agent1, "initial_input")
-  assert run_node_calls[1] == (sub_agent2, None)
-
-  assert len(events) == 1
-  assert events[0].output == "output_from_sub2"

tests/unittests/flows/llm_flows/test_agent_transfer.py

@@ -263,11 +263,23 @@ def test_auto_to_sequential(is_resumable: bool):
     assert testing_utils.simplify_resumable_app_events(runner.run('test1')) == [
         ('root_agent', transfer_call_part('sub_agent_1')),
         ('root_agent', TRANSFER_RESPONSE_PART),
+        (
+            'sub_agent_1',
+            SequentialAgentState(current_sub_agent='sub_agent_1_1').model_dump(
+                mode='json'
+            ),
+        ),
         ('sub_agent_1_1', 'response1'),
         ('sub_agent_1_1', END_OF_AGENT),
+        (
+            'sub_agent_1',
+            SequentialAgentState(current_sub_agent='sub_agent_1_2').model_dump(
+                mode='json'
+            ),
+        ),
         ('sub_agent_1_2', 'response2'),
         ('sub_agent_1_2', END_OF_AGENT),
-        ('sub_agent_1', 'response2'),
+        ('sub_agent_1', END_OF_AGENT),
         ('root_agent', END_OF_AGENT),
     ]
     # Same session, different invocation.
@@ -334,7 +346,7 @@ def test_auto_to_sequential_to_auto(is_resumable: bool):
         ('sub_agent_1_1', 'response1'),
         ('sub_agent_1_2', transfer_call_part('sub_agent_1_2_1')),
         ('sub_agent_1_2', TRANSFER_RESPONSE_PART),
-        ('sub_agent_1_2', 'response2'),
+        ('sub_agent_1_2_1', 'response2'),
         ('sub_agent_1_3', 'response3'),
     ]
 
@@ -347,16 +359,34 @@ def test_auto_to_sequential_to_auto(is_resumable: bool):
     assert testing_utils.simplify_resumable_app_events(runner.run('test1')) == [
         ('root_agent', transfer_call_part('sub_agent_1')),
         ('root_agent', TRANSFER_RESPONSE_PART),
+        (
+            'sub_agent_1',
+            SequentialAgentState(current_sub_agent='sub_agent_1_1').model_dump(
+                mode='json'
+            ),
+        ),
         ('sub_agent_1_1', 'response1'),
         ('sub_agent_1_1', END_OF_AGENT),
+        (
+            'sub_agent_1',
+            SequentialAgentState(current_sub_agent='sub_agent_1_2').model_dump(
+                mode='json'
+            ),
+        ),
         ('sub_agent_1_2', transfer_call_part('sub_agent_1_2_1')),
         ('sub_agent_1_2', TRANSFER_RESPONSE_PART),
-        ('sub_agent_1_2', 'response2'),
-        ('sub_agent_1_2', END_OF_AGENT),
+        ('sub_agent_1_2_1', 'response2'),
+        ('sub_agent_1_2_1', END_OF_AGENT),
         ('sub_agent_1_2', END_OF_AGENT),
+        (
+            'sub_agent_1',
+            SequentialAgentState(current_sub_agent='sub_agent_1_3').model_dump(
+                mode='json'
+            ),
+        ),
         ('sub_agent_1_3', 'response3'),
         ('sub_agent_1_3', END_OF_AGENT),
-        ('sub_agent_1', 'response3'),
+        ('sub_agent_1', END_OF_AGENT),
         ('root_agent', END_OF_AGENT),
     ]
     # Same session, different invocation.