fix(api): restore empty error blocks on cancelled runs (#15215)

I think this would be a subtle side effect of a previous pr trying to
improve PE end behavior.

The reason this fix is required is that when a client cancels a protocol
by stopping the engine, the `StopAction` sets the run result (good) and
doesn't set a run error (good, correct, there wasn't one, this is a
cancel). In 7.2, with the behavior this PR now restores, a
`FinishAction` that might contain an error wouldn't set that error in
the run if it already had a _result_, whether or not it had an _error_.
In 7.3, it would set the error if the engine had no error, which it
wouldn't, because there is no error when you stop.

## Testing
- [x] With this PR, cancelling a run on a real robot causes the ODD to
show an inactive error details button
- [x] With this PR, stopping a run by hitting an estop still causes the
ODD and desktop to display that an estop error cancelled the run

Closes RQA-2737

---------

Co-authored-by: Max Marrone <[email protected]>

api/src/opentrons/protocol_engine/state/commands.py

@@ -384,12 +384,21 @@ def handle_action(self, action: Action) -> None:  # noqa: C901
                 else:
                     self._state.run_result = RunResult.STOPPED
 
-            if not self._state.run_error and action.error_details:
-                self._state.run_error = self._map_run_exception_to_error_occurrence(
-                    action.error_details.error_id,
-                    action.error_details.created_at,
-                    action.error_details.error,
-                )
+                if not self._state.run_error and action.error_details:
+                    self._state.run_error = self._map_run_exception_to_error_occurrence(
+                        action.error_details.error_id,
+                        action.error_details.created_at,
+                        action.error_details.error,
+                    )
+            else:
+                # HACK(sf): There needs to be a better way to set
+                # an estop error than this else clause
+                if self._state.stopped_by_estop and action.error_details:
+                    self._state.run_error = self._map_run_exception_to_error_occurrence(
+                        action.error_details.error_id,
+                        action.error_details.created_at,
+                        action.error_details.error,
+                    )
 
         elif isinstance(action, HardwareStoppedAction):
             self._state.queue_status = QueueStatus.PAUSED

api/tests/opentrons/protocol_engine/state/test_command_state.py

@@ -469,3 +469,33 @@ def test_final_state_after_estop() -> None:
 
     assert subject_view.get_status() == EngineStatus.FAILED
     assert subject_view.get_error() == expected_error_occurrence
+
+
+def test_final_state_after_stop() -> None:
+    """Test the final state of the run after it's stopped."""
+    subject = CommandStore(config=_make_config(), is_door_open=False)
+    subject_view = CommandView(subject.state)
+
+    subject.handle_action(actions.StopAction())
+    subject.handle_action(
+        actions.FinishAction(
+            error_details=actions.FinishErrorDetails(
+                error=RuntimeError(
+                    "uh oh I was a command and then I got cancelled because someone"
+                    " stopped the run, and now I'm raising this exception because"
+                    " of that. Woe is me"
+                ),
+                error_id="error-id",
+                created_at=datetime.now(),
+            )
+        )
+    )
+    subject.handle_action(
+        actions.HardwareStoppedAction(
+            completed_at=sentinel.hardware_stopped_action_completed_at,
+            finish_error_details=None,
+        )
+    )
+
+    assert subject_view.get_status() == EngineStatus.STOPPED
+    assert subject_view.get_error() is None