fix: prevent crash when event handler raises exception

Previously, if a registered event handler raised an exception during execution,
it could crash the entire application or interrupt the event dispatch process.
This change wraps handler execution in a try/except block within the `emit` method,
ensuring that exceptions are caught and logged without affecting other handlers or flow.

This improves the resilience of the event bus, especially when handling third-party
or temporary listeners.

src/crewai/utilities/events/crewai_event_bus.py

@@ -70,7 +70,12 @@ class CrewAIEventsBus:
         for event_type, handlers in self._handlers.items():
             if isinstance(event, event_type):
                 for handler in handlers:
-                    handler(source, event)
+                    try:
+                        handler(source, event)
+                    except Exception as e:
+                        print(
+                            f"[EventBus Error] Handler '{handler.__name__}' failed for event '{event_type.__name__}': {e}"
+                        )
 
         self._signal.send(source, event=event)
 

tests/utilities/events/test_crewai_event_bus.py

@@ -32,3 +32,16 @@ def test_wildcard_event_handler():
     crewai_event_bus.emit("source_object", event)
 
     mock_handler.assert_called_once_with("source_object", event)
+
+
+def test_event_bus_error_handling(capfd):
+    @crewai_event_bus.on(BaseEvent)
+    def broken_handler(source, event):
+        raise ValueError("Simulated handler failure")
+
+    event = TestEvent(type="test_event")
+    crewai_event_bus.emit("source_object", event)
+
+    out, err = capfd.readouterr()
+    assert "Simulated handler failure" in out
+    assert "Handler 'broken_handler' failed" in out