Fix(workflow)/add _process_content_object function in _rehydration_utils file to extract output from event.content object before assigning it to child.output, in _reconstruct_node_states

src/google/adk/workflow/utils/_rehydration_utils.py

@@ -96,6 +96,25 @@ def _extract_schema_from_event(event: Event, interrupt_id: str) -> Any | None:
   return None
 
 
+def _process_content_object(event: Event) -> Any:
+  """Extracts output from event.content."""
+  if not event.content or not getattr(event.content, 'parts', None):
+    return None
+
+  text = ''.join(
+    p.text for p in event.content.parts if p.text and not p.thought
+  )
+  text = text.strip()
+
+  if not text:
+    return None
+
+  try:
+    return json.loads(text)
+  except (json.JSONDecodeError, ValueError):
+    return text
+
+
 def _validate_resume_response(response_data: Any, schema: Any) -> Any:
   """Validates and coerces resume response data against a schema.
 
@@ -275,7 +294,7 @@ def get_owner_key(event_path_builder: _NodePathBuilder) -> str | None:
         child.output = event.output
         child.branch = event.branch
       elif use_message_as_output:
-        child.output = event.content
+        child.output = _process_content_object(event)
       if event.actions and event.actions.route is not None:
         child.route = event.actions.route
       if event.actions and event.actions.transfer_to_agent is not None:

tests/unittests/workflow/utils/test_rehydration_utils.py

@@ -18,6 +18,7 @@
 from google.adk.events.event import NodeInfo
 from google.adk.events.request_input import RequestInput
 from google.adk.workflow.utils._rehydration_utils import _ChildScanState
+from google.adk.workflow.utils._rehydration_utils import _process_content_object
 from google.adk.workflow.utils._rehydration_utils import _reconstruct_node_states
 from google.adk.workflow.utils._rehydration_utils import _unwrap_response
 from google.adk.workflow.utils._rehydration_utils import _validate_resume_response
@@ -103,6 +104,48 @@ def test_roundtrip_wrap_unwrap_dict(self):
     assert _unwrap_response(_wrap_response(d)) == d
 
 
+# --- _process_content_object ---
+
+
+class TestProcessContentObject:
+
+  def test_extracts_plain_text(self):
+    content = types.Content(parts=[types.Part(text="hello world")])
+    event = Event(content=content, invocation_id="id")
+    assert _process_content_object(event) == "hello world"
+
+  def test_parses_json_text(self):
+    content = types.Content(parts=[types.Part(text='{"foo": "bar"}')])
+    event = Event(content=content, invocation_id="id")
+    assert _process_content_object(event) == {"foo": "bar"}
+
+  def test_joins_multiple_parts(self):
+    content = types.Content(
+        parts=[types.Part(text="hello "), types.Part(text="world")]
+    )
+    event = Event(content=content, invocation_id="id")
+    assert _process_content_object(event) == "hello world"
+
+  def test_filters_thought_parts(self):
+    content = types.Content(
+        parts=[
+            types.Part(text="thinking...", thought=True),
+            types.Part(text='{"answer": 42}'),
+        ]
+    )
+    event = Event(content=content, invocation_id="id")
+    assert _process_content_object(event) == {"answer": 42}
+
+  def test_returns_none_for_no_content(self):
+    event = Event(invocation_id="id")
+    assert _process_content_object(event) is None
+
+  def test_returns_none_for_empty_text(self):
+    content = types.Content(parts=[types.Part(text="  ")])
+    event = Event(content=content, invocation_id="id")
+    assert _process_content_object(event) is None
+
+
 # --- _validate_resume_response ---
 
 
@@ -192,7 +235,7 @@ def test_scan_message_as_output(self):
     )
 
     assert "node_a@1" in results
-    assert results["node_a@1"].output == content
+    assert results["node_a@1"].output == "hello"
 
   def test_scan_descendant_interrupts(self):
     event = Event(