Scheduler try catch (#2037)

* try catch in SchedulerImpl to individually fail tasks

* Use exception manager

* chore: add a test

---------

Co-authored-by: mworzala <mattheworzala@gmail.com>

src/main/java/net/minestom/server/timer/SchedulerImpl.java

@@ -1,6 +1,7 @@
 package net.minestom.server.timer;
 
 import it.unimi.dsi.fastutil.ints.Int2ObjectAVLTreeMap;
+import net.minestom.server.MinecraftServer;
 import org.jctools.queues.MpscUnboundedArrayQueue;
 import org.jetbrains.annotations.NotNull;
 
@@ -89,7 +90,14 @@ final class SchedulerImpl implements Scheduler {
     }
 
     private void handleTask(TaskImpl task) {
-        final TaskSchedule schedule = task.task().get();
+        TaskSchedule schedule;
+        try {
+            schedule = task.task().get();
+        } catch (Throwable t) {
+            MinecraftServer.getExceptionManager().handleException(new RuntimeException("Exception in scheduled task", t));
+            schedule = TaskSchedule.stop();
+        }
+
         if (schedule instanceof TaskScheduleImpl.DurationSchedule durationSchedule) {
             final Duration duration = durationSchedule.duration();
             SCHEDULER.schedule(() -> safeExecute(task), duration.toMillis(), TimeUnit.MILLISECONDS);

src/test/java/net/minestom/server/timer/TestScheduler.java

@@ -1,10 +1,12 @@
 package net.minestom.server.timer;
 
+import net.minestom.server.MinecraftServer;
 import org.junit.jupiter.api.Test;
 
 import java.time.Duration;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -139,4 +141,24 @@ public class TestScheduler {
         Thread.sleep(250);
         assertTrue(result.get(), "Async task didn't get executed");
     }
+
+    @Test
+    public void exceptionTask() {
+        MinecraftServer.init();
+        Scheduler scheduler = Scheduler.newScheduler();
+        scheduler.scheduleNextTick(() -> {
+            throw new RuntimeException("Test exception");
+        });
+
+        // This is a bit of a weird use case. I dont want this test to depend on the order the scheduler executes in
+        // so this is a guess that the first one wont be before all 100 of the ones scheduled below.
+        // Not great, but should be fine anyway.
+        AtomicInteger executed = new AtomicInteger(0);
+        for (int i = 0; i < 100; i++) {
+            scheduler.scheduleNextTick(executed::incrementAndGet);
+        }
+
+        assertDoesNotThrow(scheduler::processTick);
+        assertEquals(100, executed.get());
+    }
 }