avm2: Continue to process event when a handler produces an error

An exception thrown by one event handler shoud not prevent other event
handlers from running on this same event. Some SWFs like Wonderputt
depend on this behavior, as they have buggy event handlers that throw
errors.

Author: Aaron1011

core/src/avm2/events.rs

@@ -417,7 +417,14 @@ pub fn dispatch_event_to_target<'gc>(
 
         let object = activation.global_scope();
 
-        handler.call(object, &[event.into()], activation)?;
+        if let Err(err) = handler.call(object, &[event.into()], activation) {
+            log::error!(
+                "Error dispatching event {:?} to handler {:?} : {:?}",
+                event,
+                handler,
+                err
+            );
+        }
     }
 
     Ok(())

tests/tests/regression_tests.rs

@@ -260,6 +260,7 @@ swf_tests! {
     (as3_event_cancelable, "avm2/event_cancelable", 1),
     (as3_event_clone, "avm2/event_clone", 1),
     (as3_event_formattostring, "avm2/event_formattostring", 1),
+    (as3_event_handler_exception, "avm2/event_handler_exception", 2),
     (as3_event_isdefaultprevented, "avm2/event_isdefaultprevented", 1),
     (as3_event_type, "avm2/event_type", 1),
     (as3_event_valueof_tostring, "avm2/event_valueof_tostring", 1),

tests/tests/swfs/avm2/event_handler_exception/Test.as

@@ -0,0 +1,30 @@
+package {
+	import flash.events.Event;
+	import flash.display.Sprite;
+	import flash.display.Stage;
+	
+	public class Test {
+		public function Test(stage: Stage) {
+			stage.addEventListener(Event.ENTER_FRAME, function() {
+				trace("First listener!");
+				throw new Error("Exception in first listener");
+			});
+
+			stage.addEventListener(Event.ENTER_FRAME, function() {
+				trace("Second listener!");
+
+				var sprite = new Sprite();
+				sprite.addEventListener("customEvent", function() {
+					trace("First custom event listener!");
+					throw new Error("Exception in custom event handler");
+				});
+
+				sprite.addEventListener("customEvent", function() {
+					trace("Second custom event listener!");
+				});
+
+				sprite.dispatchEvent(new Event("customEvent"));	
+			});		
+		}
+	}
+}

tests/tests/swfs/avm2/event_handler_exception/output.txt

@@ -0,0 +1,4 @@
+First listener!
+Second listener!
+First custom event listener!
+Second custom event listener!