Handle trace without lifecycle transitions (#28)

Signed-off-by: Christophe Bedard <christophe.bedard@apex.ai>

tracetools_analysis/test/tracetools_analysis/test_utils.py

@@ -39,3 +39,9 @@ def test_ros2_no_callbacks(self) -> None:
         data_model.finalize()
         util = Ros2DataModelUtil(data_model)
         self.assertEqual({}, util.get_callback_symbols())
+
+    def test_ros2_no_lifecycle_transitions(self) -> None:
+        data_model = Ros2DataModel()
+        data_model.finalize()
+        util = Ros2DataModelUtil(data_model)
+        self.assertEqual({}, util.get_lifecycle_node_state_intervals())

tracetools_analysis/tracetools_analysis/utils/ros2.py

@@ -17,6 +17,7 @@
 """Module for ROS data model utils."""
 
 from typing import Any
+from typing import Dict
 from typing import List
 from typing import Mapping
 from typing import Optional
@@ -117,7 +118,7 @@ def get_callback_symbols(self) -> Mapping[int, str]:
         callback_instances = self.data.callback_instances
         callback_symbols = self.data.callback_symbols
 
-        if 'callback_object' not in callback_instances.columns:
+        if callback_instances.empty:
             return {}
 
         # Get a list of callback objects
@@ -507,7 +508,7 @@ def get_lifecycle_node_handle_info(
 
     def get_lifecycle_node_state_intervals(
         self,
-    ) -> DataFrame:
+    ) -> Dict[int, DataFrame]:
         """
         Get state intervals (start, end) for all lifecycle nodes.
 
@@ -522,8 +523,11 @@ def get_lifecycle_node_state_intervals(
         :return: dictionary with a dataframe (with each row containing state interval information)
             for each lifecycle node
         """
-        data = {}
         lifecycle_transitions = self.data.lifecycle_transitions.copy()
+        if lifecycle_transitions.empty:
+            return {}
+
+        data = {}
         state_machine_handles = set(lifecycle_transitions['state_machine_handle'])
         for state_machine_handle in state_machine_handles:
             transitions = lifecycle_transitions.loc[