fix: support nested agent paths in dot_adk_folder resolution

Updates dot_adk_folder_for_agent to resolve app names containing dots (e.g., "parent.child") to nested subdirectories (e.g., "parent/child") instead of a single flat directory. This ensures that local storage and session databases are correctly located for nested agents

Co-authored-by: Yifan Wang <wanyif@google.com>
PiperOrigin-RevId: 952905400

Author: wyf7107

src/google/adk/cli/utils/dot_adk_folder.py

@@ -23,6 +23,8 @@ def _resolve_agent_dir(*, agents_root: Path | str, app_name: str) -> Path:
   """Resolves the agent directory with safety checks."""
   agents_root_path = Path(agents_root).resolve()
   agent_dir = (agents_root_path / app_name).resolve()
+  if "." in app_name:
+    agent_dir = (agents_root_path / app_name.replace(".", "/")).resolve()
   if not agent_dir.is_relative_to(agents_root_path):
     raise ValueError(
         f"Invalid app_name '{app_name}': resolves outside base directory"

tests/unittests/cli/utils/test_dot_adk_folder.py

@@ -55,3 +55,15 @@ def test_for_agent_rejects_prefix_sibling_escape(tmp_path: Path):
   # "agents_evil"); a startswith() check would wrongly accept this.
   with pytest.raises(ValueError):
     dot_adk_folder_for_agent(agents_root=agents_root, app_name="../agents_evil")
+
+
+def test_for_agent_resolves_nested_agent(tmp_path: Path):
+  agents_root = tmp_path / "agents"
+  nested_agent = agents_root / "multi_agent" / "hello_world_ma"
+  nested_agent.mkdir(parents=True)
+
+  folder = dot_adk_folder_for_agent(
+      agents_root=agents_root, app_name="multi_agent.hello_world_ma"
+  )
+
+  assert folder.agent_dir == nested_agent.resolve()

tests/unittests/cli/utils/test_local_storage.py

@@ -54,6 +54,22 @@ async def test_per_agent_session_service_creates_scoped_dot_adk(
     assert agent_b_sessions.sessions[0].app_name == "agent_b"
 
 
+@pytest.mark.asyncio
+async def test_per_agent_session_service_supports_nested_agent_path(
+    tmp_path: Path,
+) -> None:
+  nested_agent = tmp_path / "multi_agent" / "hello_world_ma"
+  nested_agent.mkdir(parents=True)
+
+  async with PerAgentDatabaseSessionService(agents_root=tmp_path) as service:
+    await service.create_session(
+        app_name="multi_agent.hello_world_ma", user_id="user_a"
+    )
+
+    assert (nested_agent / ".adk" / "session.db").exists()
+    assert not (tmp_path / "multi_agent.hello_world_ma").exists()
+
+
 @pytest.mark.asyncio
 async def test_per_agent_session_service_respects_app_name_alias(
     tmp_path: Path,