Make EffTeleport do teleports asynchronously on Paper

build.gradle

@@ -2,15 +2,20 @@ import org.apache.tools.ant.filters.ReplaceTokens
 
 plugins {
 	id "com.github.hierynomus.license" version "0.14.0"
+	id "com.github.johnrengelman.shadow" version "5.2.0"
 }
 
 apply plugin: 'java'
 apply plugin: 'maven-publish'
 
+ext {
+	paperVersion = '1.16.3-R0.1-SNAPSHOT' // NOTICE: Edit this when updating to a new MC Version
+}
+
 // Substitute dependencies' versions of Bukkit with latest Paper API
 configurations.all {
 	resolutionStrategy.dependencySubstitution {
-		substitute module('org.bukkit:bukkit') with module('com.destroystokyo.paper:paper-api:1.14-R0.1-SNAPSHOT')
+		substitute module('org.bukkit:bukkit') with module("com.destroystokyo.paper:paper-api:${paperVersion}")
 	}
 }
 
@@ -28,7 +33,7 @@ allprojects {
 		}
 
 		maven {
-			url 'https://repo.destroystokyo.com/repository/maven-public//'
+			url 'https://papermc.io/repo/repository/maven-public/'
 		}
 
 		maven {
@@ -50,8 +55,10 @@ allprojects {
 
 	configurations {
 		ecj
+		shade
+		implementation.extendsFrom(shade)
 	}
-	
+
 	dependencies {
 		ecj 'org.eclipse.jdt:ecj:3.15.0'
 	}
@@ -70,14 +77,15 @@ allprojects {
 }
 
 dependencies {
-	implementation 'com.destroystokyo.paper:paper-api:1.16.2-R0.1-SNAPSHOT'
+	implementation "com.destroystokyo.paper:paper-api:${paperVersion}"
 	implementation 'org.eclipse.jdt:org.eclipse.jdt.annotation:1.1.0'
 	implementation 'com.google.code.findbugs:findbugs:3.0.1'
 	implementation 'com.sk89q.worldguard:worldguard-legacy:7.0.0-SNAPSHOT'
 	implementation 'com.github.marcelo-mason:PreciousStones:24e3d4bf67b7240ae36b32be10e99d4091938c5c'
 	implementation('net.milkbowl.vault:Vault:1.7.1') {
 		exclude group: 'org.bstats', module: 'bstats-bukkit'
 	}
+	shade 'io.papermc:paperlib:1.0.5'
 
 	testImplementation 'junit:junit:4.12'
 	testImplementation 'org.easymock:easymock:3.6'
@@ -97,23 +105,40 @@ processResources {
 	]
 }
 
-jar {
+task jar(overwrite: true, type: ShadowJar) {
 	archiveName System.getenv('SKRIPT_JAR_NAME') == null ? 'Skript.jar' : System.getenv("SKRIPT_JAR_NAME")
+	from sourceSets.main.output
+}
+
+//jar.dependsOn shadowJar
+tasks.withType(ShadowJar) {
+	configurations = [project.configurations.shade]
+	dependencies {
+		include (dependency('io.papermc:paperlib'))
+	}
+	relocate 'io.papermc.lib', 'ch.njol.skript.paperlib'
 
 	manifest {
 		attributes("Name": "ch/njol/skript",
-				"Sealed": "true")
+			"Sealed": "true")
 	}
 
 	from('skript-aliases') {
 		into('aliases-english') // Change this if we get aliases in other languages
 	}
-	
+
 	// Include all modules of Skript
 	from 'skript-worldguard6/build/classes/java/main'
 	from 'skript-worldguard7fawe/build/classes/java/main'
 }
 
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+import com.github.jengelman.gradle.plugins.shadow.tasks.ConfigureShadowRelocation
+task relocateShadowJar(type: ConfigureShadowRelocation) {
+	target = tasks.shadowJar
+}
+tasks.shadowJar.dependsOn tasks.relocateShadowJar
+
 license {
 	header file('licenseheader.txt')
 	exclude('**/Metrics.java') // Not under GPLv3
@@ -236,7 +261,7 @@ task githubResources(type: ProcessResources) {
 	into 'build/resources/main'
 }
 
-task githubRelease(type: Jar) {
+task githubRelease(type: ShadowJar) {
 	from sourceSets.main.output
 	dependsOn githubResources
 	archiveName = 'Skript-github.jar'
@@ -278,7 +303,7 @@ task spigotResources(type: ProcessResources) {
 	into 'build/resources/main'
 }
 
-task spigotRelease(type: Jar) {
+task spigotRelease(type: ShadowJar) {
 	from sourceSets.main.output
 	dependsOn spigotResources
 	archiveName = 'Skript-spigot.jar'
@@ -315,7 +340,7 @@ task nightlyResources(type: ProcessResources) {
 	into 'build/resources/main'
 }
 
-task nightlyRelease(type: Jar) {
+task nightlyRelease(type: ShadowJar) {
 	from sourceSets.main.output
 	dependsOn nightlyResources
 	dependsOn licenseMain

src/main/java/ch/njol/skript/effects/EffTeleport.java

@@ -35,8 +35,13 @@
 import ch.njol.skript.lang.Effect;
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.SkriptParser.ParseResult;
+import ch.njol.skript.lang.Trigger;
+import ch.njol.skript.lang.TriggerItem;
+import ch.njol.skript.timings.SkriptTimings;
 import ch.njol.skript.util.Direction;
+import ch.njol.skript.variables.Variables;
 import ch.njol.util.Kleenean;
+import io.papermc.lib.PaperLib;
 
 @Name("Teleport")
 @Description("Teleport an entity to a specific location.")
@@ -61,28 +66,73 @@ public boolean init(final Expression<?>[] exprs, final int matchedPattern, final
 		location = Direction.combine((Expression<? extends Direction>) exprs[1], (Expression<? extends Location>) exprs[2]);
 		return true;
 	}
-
+
+	@Nullable
 	@Override
-	protected void execute(final Event e) {
-		Location to = location.getSingle(e);
-		if (to == null)
-			return;
-		if (Math.abs(to.getX() - to.getBlockX() - 0.5) < Skript.EPSILON && Math.abs(to.getZ() - to.getBlockZ() - 0.5) < Skript.EPSILON) {
-			final Block on = to.getBlock().getRelative(BlockFace.DOWN);
+	protected TriggerItem walk(Event e) {
+		debug(e, true);
+		TriggerItem next = getNext();
+		boolean delayed = Delay.isDelayed(e);
+		Delay.addDelayedEvent(e);
+
+		final Location loc = location.getSingle(e);
+		final Entity[] entityArray = entities.getArray(e); // We have to fetch this before possible async execution to avoid async local variable access.
+		final boolean respawnEvent = !delayed && e instanceof PlayerRespawnEvent && entityArray.length == 1 && entityArray[0].equals(((PlayerRespawnEvent) e).getPlayer());
+
+		if (respawnEvent && loc != null) {
+			((PlayerRespawnEvent) e).setRespawnLocation(getSafeLocation(loc));
+		}
+
+		if (respawnEvent || loc == null) {
+			continueWalk(next, e);
+			return null;
+		}
+
+		//This will either fetch the chunk instantly if on spigot or already loaded or fetch it async if on paper.
+		PaperLib.getChunkAtAsync(loc).thenAccept(chunk -> {
+			// The following is now on the main thread
+			for (final Entity entity : entityArray) {
+				entity.teleport(getSafeLocation(loc));
+			}
+
+			// Continue the rest of the trigger if there is one
+			continueWalk(next, e);
+		});
+		return null;
+	}
+
+	private void continueWalk(@Nullable TriggerItem next, Event e) {
+		Object timing = null;
+		if (next != null) {
+			if (SkriptTimings.enabled()) {
+				Trigger trigger = getTrigger();
+				if (trigger != null) {
+					timing = SkriptTimings.start(trigger.getDebugLabel());
+				}
+			}
+
+			TriggerItem.walk(next, e);
+		}
+		Variables.removeLocals(e); // Clean up local vars, we may be exiting now
+		SkriptTimings.stop(timing);
+	}
+
+	private Location getSafeLocation(Location loc) {
+		Location toLoc = loc;
+		if (Math.abs(toLoc.getX() - toLoc.getBlockX() - 0.5) < Skript.EPSILON && Math.abs(toLoc.getZ() - toLoc.getBlockZ() - 0.5) < Skript.EPSILON) {
+			final Block on = toLoc.getBlock().getRelative(BlockFace.DOWN);
 			if (on.getType() != Material.AIR) {
-				to = to.clone();
+				toLoc = toLoc.clone();
 				// TODO 1.13 block height stuff
 				//to.setY(on.getY() + Utils.getBlockHeight(on.getTypeId(), on.getData()));
 			}
 		}
-		for (final Entity entity : entities.getArray(e)) {
-			to.getChunk().load();
-			if (e instanceof PlayerRespawnEvent && entity.equals(((PlayerRespawnEvent) e).getPlayer()) && !Delay.isDelayed(e)) {
-				((PlayerRespawnEvent) e).setRespawnLocation(to);
-			} else {
-				entity.teleport(to);
-			}
-		}
+		return toLoc;
+	}
+
+	@Override
+	protected void execute(final Event e) {
+		// Nothing needs to happen here, we're executing in walk
 	}
 
 	@Override