Route hybrid schedulers

- Select Bukkit scheduling only when the bound platform identifies as Bukkit.
- Route hybrid Youer hosts through the modded scheduler despite Bukkit classes on the classpath.
- Add regression coverage for Bukkit and NeoForge platform identities.

core/src/main/java/art/arcane/iris/util/common/scheduling/J.java

@@ -121,7 +121,7 @@ public class J {
     }
 
     public static void aBukkit(Runnable a) {
-        if (!BUKKIT_PRESENT) {
+        if (!usesBukkitScheduler()) {
             if (IrisPlatforms.isBound()) {
                 IrisPlatforms.get().scheduler().async(a);
             }
@@ -186,7 +186,7 @@ public class J {
     }
 
     public static boolean isFolia() {
-        return BUKKIT_PRESENT && FoliaScheduler.isFolia(Bukkit.getServer());
+        return usesBukkitScheduler() && FoliaScheduler.isFolia(Bukkit.getServer());
     }
 
     public static boolean isPrimaryThread() {
@@ -345,7 +345,7 @@ public class J {
             return false;
         }
 
-        if (!BUKKIT_PRESENT) {
+        if (!usesBukkitScheduler()) {
             if (!IrisPlatforms.isBound()) {
                 return false;
             }
@@ -416,7 +416,7 @@ public class J {
 
     public static void cancelPluginTasks() {
         cancelTrackedRepeatingTasks();
-        if (!BukkitPlatform.hasPlugin()) {
+        if (!usesBukkitScheduler() || !BukkitPlatform.hasPlugin()) {
             return;
         }
 
@@ -442,7 +442,7 @@ public class J {
     }
 
     public static void s(Runnable r) {
-        if (!BUKKIT_PRESENT) {
+        if (!usesBukkitScheduler()) {
             if (IrisPlatforms.isBound()) {
                 IrisPlatforms.get().scheduler().global(r);
             }
@@ -566,7 +566,7 @@ public class J {
     }
 
     public static void s(Runnable r, int delay) {
-        if (!BUKKIT_PRESENT) {
+        if (!usesBukkitScheduler()) {
             if (IrisPlatforms.isBound()) {
                 IrisPlatforms.get().scheduler().laterGlobal(r, delay);
             }
@@ -667,7 +667,7 @@ public class J {
     }
 
     public static void a(Runnable r, int delay) {
-        if (!BUKKIT_PRESENT) {
+        if (!usesBukkitScheduler()) {
             if (IrisPlatforms.isBound()) {
                 if (delay <= 0) {
                     IrisPlatforms.get().scheduler().async(r);
@@ -772,11 +772,17 @@ public class J {
     }
 
     private static boolean isPluginEnabled() {
-        return BUKKIT_PRESENT && BukkitPlatform.hasPlugin() && Bukkit.getPluginManager().isPluginEnabled(BukkitPlatform.plugin());
+        return usesBukkitScheduler() && BukkitPlatform.hasPlugin() && Bukkit.getPluginManager().isPluginEnabled(BukkitPlatform.plugin());
     }
 
     private static boolean canSchedule() {
-        return BUKKIT_PRESENT ? isPluginEnabled() : IrisPlatforms.isBound();
+        return usesBukkitScheduler() ? isPluginEnabled() : IrisPlatforms.isBound();
+    }
+
+    static boolean usesBukkitScheduler() {
+        return BUKKIT_PRESENT
+                && IrisPlatforms.isBound()
+                && "bukkit".equalsIgnoreCase(IrisPlatforms.get().platformName());
     }
 
     private static long ticksToMilliseconds(int ticks) {

core/src/test/java/art/arcane/iris/util/common/scheduling/JHybridPlatformTest.java

@@ -0,0 +1,55 @@
+package art.arcane.iris.util.common.scheduling;
+
+import art.arcane.iris.spi.IrisPlatform;
+import art.arcane.iris.spi.IrisPlatforms;
+import art.arcane.iris.spi.PlatformScheduler;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.assertNotEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+public class JHybridPlatformTest {
+    @Before
+    public void clearPlatform() {
+        IrisPlatforms.unbind();
+    }
+
+    @After
+    public void cleanup() {
+        J.cancelTrackedRepeatingTasks();
+        IrisPlatforms.unbind();
+    }
+
+    @Test
+    public void boundBukkitIdentitySelectsBukkitScheduler() {
+        IrisPlatform platform = mock(IrisPlatform.class);
+        when(platform.platformName()).thenReturn("bukkit");
+        IrisPlatforms.bind(platform);
+
+        assertTrue(J.usesBukkitScheduler());
+    }
+
+    @Test
+    public void hybridHostRepeaterUsesBoundModdedScheduler() {
+        IrisPlatform platform = mock(IrisPlatform.class);
+        PlatformScheduler scheduler = mock(PlatformScheduler.class);
+        when(platform.platformName()).thenReturn("neoforge");
+        when(platform.scheduler()).thenReturn(scheduler);
+        IrisPlatforms.bind(platform);
+
+        assertFalse(J.usesBukkitScheduler());
+        int taskId = J.ar(() -> {
+        }, 1);
+
+        assertNotEquals(-1, taskId);
+        verify(scheduler).laterGlobal(any(Runnable.class), eq(1));
+    }
+}