Added a generic Promise type

I anticipate increasing demand for promises, and since all the libraries I could find suck, we'll stick to our own impl for now.

src/Server.php

@@ -70,7 +70,6 @@ use pocketmine\permission\DefaultPermissions;
 use pocketmine\player\GameMode;
 use pocketmine\player\OfflinePlayer;
 use pocketmine\player\Player;
-use pocketmine\player\PlayerCreationPromise;
 use pocketmine\player\PlayerInfo;
 use pocketmine\plugin\PharPluginLoader;
 use pocketmine\plugin\Plugin;
@@ -93,6 +92,7 @@ use pocketmine\utils\Filesystem;
 use pocketmine\utils\Internet;
 use pocketmine\utils\MainLogger;
 use pocketmine\utils\Process;
+use pocketmine\utils\Promise;
 use pocketmine\utils\Terminal;
 use pocketmine\utils\TextFormat;
 use pocketmine\utils\Utils;
@@ -580,7 +580,10 @@ class Server{
 		}
 	}
 
-	public function createPlayer(NetworkSession $session, PlayerInfo $playerInfo, bool $authenticated, ?CompoundTag $offlinePlayerData) : PlayerCreationPromise{
+	/**
+	 * @phpstan-return Promise<Player>
+	 */
+	public function createPlayer(NetworkSession $session, PlayerInfo $playerInfo, bool $authenticated, ?CompoundTag $offlinePlayerData) : Promise{
 		$ev = new PlayerCreationEvent($session);
 		$ev->call();
 		$class = $ev->getPlayerClass();
@@ -596,7 +599,7 @@ class Server{
 			$playerPos = null;
 			$spawn = $world->getSpawnLocation();
 		}
-		$playerPromise = new PlayerCreationPromise();
+		$playerPromise = new Promise();
 		$world->requestChunkPopulation($spawn->getFloorX() >> 4, $spawn->getFloorZ() >> 4, null)->onCompletion(
 			function() use ($playerPromise, $class, $session, $playerInfo, $authenticated, $world, $playerPos, $spawn, $offlinePlayerData) : void{
 				if(!$session->isConnected()){

src/utils/Promise.php

@@ -21,14 +21,17 @@
 
 declare(strict_types=1);
 
-namespace pocketmine\player;
+namespace pocketmine\utils;
 
 use function spl_object_id;
 
-final class PlayerCreationPromise{
+/**
+ * @phpstan-template TValue
+ */
+final class Promise{
 	/**
 	 * @var \Closure[]
-	 * @phpstan-var array<int, \Closure(Player) : void>
+	 * @phpstan-var array<int, \Closure(TValue) : void>
 	 */
 	private array $onSuccess = [];
 
@@ -39,10 +42,15 @@ final class PlayerCreationPromise{
 	private array $onFailure = [];
 
 	private bool $resolved = false;
-	private ?Player $result = null;
 
 	/**
-	 * @phpstan-param \Closure(Player) : void $onSuccess
+	 * @var mixed
+	 * @phpstan-var TValue|null
+	 */
+	private $result = null;
+
+	/**
+	 * @phpstan-param \Closure(TValue) : void $onSuccess
 	 * @phpstan-param \Closure() : void $onFailure
 	 */
 	public function onCompletion(\Closure $onSuccess, \Closure $onFailure) : void{
@@ -54,17 +62,27 @@ final class PlayerCreationPromise{
 		}
 	}
 
-	public function resolve(Player $player) : void{
+	/**
+	 * @param mixed $value
+	 * @phpstan-param TValue $value
+	 */
+	public function resolve($value) : void{
+		if($this->resolved){
+			throw new \InvalidStateException("Promise has already been resolved/rejected");
+		}
 		$this->resolved = true;
-		$this->result = $player;
+		$this->result = $value;
 		foreach($this->onSuccess as $c){
-			$c($player);
+			$c($value);
 		}
 		$this->onSuccess = [];
 		$this->onFailure = [];
 	}
 
 	public function reject() : void{
+		if($this->resolved){
+			throw new \InvalidStateException("Promise has already been resolved/rejected");
+		}
 		$this->resolved = true;
 		foreach($this->onFailure as $c){
 			$c();

src/world/ChunkPopulationPromise.php

@@ -1,76 +0,0 @@
-<?php
-
-/*
- *
- *  ____            _        _   __  __ _                  __  __ ____
- * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
- * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
- * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
- * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * @author PocketMine Team
- * @link http://www.pocketmine.net/
- *
- *
-*/
-
-declare(strict_types=1);
-
-namespace pocketmine\world;
-
-use function spl_object_id;
-
-final class ChunkPopulationPromise{
-	/**
-	 * @var \Closure[]
-	 * @phpstan-var array<int, \Closure() : void>
-	 */
-	private array $onSuccess = [];
-	/**
-	 * @var \Closure[]
-	 * @phpstan-var array<int, \Closure() : void>
-	 */
-	private array $onFailure = [];
-
-	private ?bool $success = null;
-
-	/**
-	 * @phpstan-param \Closure() : void $onSuccess
-	 * @phpstan-param \Closure() : void $onFailure
-	 */
-	public function onCompletion(\Closure $onSuccess, \Closure $onFailure) : void{
-		if($this->success !== null){
-			$this->success ? $onSuccess() : $onFailure();
-		}else{
-			$this->onSuccess[spl_object_id($onSuccess)] = $onSuccess;
-			$this->onFailure[spl_object_id($onFailure)] = $onFailure;
-		}
-	}
-
-	public function resolve() : void{
-		$this->success = true;
-		foreach($this->onSuccess as $callback){
-			$callback();
-		}
-		$this->onSuccess = [];
-		$this->onFailure = [];
-	}
-
-	public function reject() : void{
-		$this->success = false;
-		foreach($this->onFailure as $callback){
-			$callback();
-		}
-		$this->onSuccess = [];
-		$this->onFailure = [];
-	}
-
-	public function isCompleted() : bool{
-		return $this->success !== null;
-	}
-}

src/world/World.php

@@ -68,6 +68,7 @@ use pocketmine\Server;
 use pocketmine\timings\Timings;
 use pocketmine\utils\AssumptionFailedError;
 use pocketmine\utils\Limits;
+use pocketmine\utils\Promise;
 use pocketmine\utils\ReversePriorityQueue;
 use pocketmine\world\biome\Biome;
 use pocketmine\world\biome\BiomeRegistry;
@@ -240,8 +241,8 @@ class World implements ChunkManager{
 	/** @var int */
 	private $maxConcurrentChunkPopulationTasks = 2;
 	/**
-	 * @var ChunkPopulationPromise[] chunkHash => promise
-	 * @phpstan-var array<int, ChunkPopulationPromise>
+	 * @var Promise[] chunkHash => promise
+	 * @phpstan-var array<int, Promise<Chunk>>
 	 */
 	private array $chunkPopulationRequestMap = [];
 	/**
@@ -2110,7 +2111,7 @@ class World implements ChunkManager{
 				}
 			}
 			unset($this->activeChunkPopulationTasks[$index]);
-			$this->chunkPopulationRequestMap[$index]->resolve();
+			$this->chunkPopulationRequestMap[$index]->resolve($chunk);
 			unset($this->chunkPopulationRequestMap[$index]);
 
 			$this->drainPopulationRequestQueue();
@@ -2698,10 +2699,13 @@ class World implements ChunkManager{
 		}
 	}
 
-	private function enqueuePopulationRequest(int $chunkX, int $chunkZ, ?ChunkLoader $associatedChunkLoader) : ChunkPopulationPromise{
+	/**
+	 * @phpstan-return Promise<Chunk>
+	 */
+	private function enqueuePopulationRequest(int $chunkX, int $chunkZ, ?ChunkLoader $associatedChunkLoader) : Promise{
 		$chunkHash = World::chunkHash($chunkX, $chunkZ);
 		$this->chunkPopulationRequestQueue->enqueue($chunkHash);
-		$promise = $this->chunkPopulationRequestMap[$chunkHash] = new ChunkPopulationPromise();
+		$promise = $this->chunkPopulationRequestMap[$chunkHash] = new Promise();
 		if($associatedChunkLoader === null){
 			$temporaryLoader = new class implements ChunkLoader{};
 			$this->registerChunkLoader($temporaryLoader, $chunkX, $chunkZ);
@@ -2721,8 +2725,10 @@ class World implements ChunkManager{
 	 * A ChunkLoader can be associated with the generation request to ensure that the generation request is cancelled if
 	 * no loaders are attached to the target chunk. If no loader is provided, one will be assigned (and automatically
 	 * removed when the generation request completes).
+	 *
+	 * @phpstan-return Promise<Chunk>
 	 */
-	public function requestChunkPopulation(int $chunkX, int $chunkZ, ?ChunkLoader $associatedChunkLoader) : ChunkPopulationPromise{
+	public function requestChunkPopulation(int $chunkX, int $chunkZ, ?ChunkLoader $associatedChunkLoader) : Promise{
 		$chunkHash = World::chunkHash($chunkX, $chunkZ);
 		$promise = $this->chunkPopulationRequestMap[$chunkHash] ?? null;
 		if($promise !== null && isset($this->activeChunkPopulationTasks[$chunkHash])){
@@ -2743,8 +2749,10 @@ class World implements ChunkManager{
 	 *
 	 * If the chunk is currently locked (for example due to another chunk using it for async generation), the request
 	 * will be queued and executed at the earliest opportunity.
+	 *
+	 * @phpstan-return Promise<Chunk>
 	 */
-	public function orderChunkPopulation(int $x, int $z, ?ChunkLoader $associatedChunkLoader) : ChunkPopulationPromise{
+	public function orderChunkPopulation(int $x, int $z, ?ChunkLoader $associatedChunkLoader) : Promise{
 		$index = World::chunkHash($x, $z);
 		$promise = $this->chunkPopulationRequestMap[$index] ?? null;
 		if($promise !== null && isset($this->activeChunkPopulationTasks[$index])){
@@ -2766,7 +2774,7 @@ class World implements ChunkManager{
 
 			$this->activeChunkPopulationTasks[$index] = true;
 			if($promise === null){
-				$promise = new ChunkPopulationPromise();
+				$promise = new Promise();
 				$this->chunkPopulationRequestMap[$index] = $promise;
 			}
 
@@ -2788,8 +2796,8 @@ class World implements ChunkManager{
 		}
 
 		//chunk is already populated; return a pre-resolved promise that will directly fire callbacks assigned
-		$result = new ChunkPopulationPromise();
-		$result->resolve();
+		$result = new Promise();
+		$result->resolve($chunk);
 		return $result;
 	}
 

tests/phpstan/configs/phpstan-bugs.neon

@@ -20,6 +20,16 @@ parameters:
 			count: 1
 			path: ../../../src/entity/projectile/Projectile.php
 
+		-
+			message: "#^Parameter \\#1 \\$ of closure expects TValue, TValue given\\.$#"
+			count: 2
+			path: ../../../src/utils/Promise.php
+
+		-
+			message: "#^Property pocketmine\\\\utils\\\\Promise\\<TValue\\>\\:\\:\\$result \\(TValue\\|null\\) does not accept TValue\\.$#"
+			count: 1
+			path: ../../../src/utils/Promise.php
+
 		-
 			message: "#^Parameter \\#1 \\$ of closure expects TMemberType, TMemberType given\\.$#"
 			count: 1