Chained promises should always resolve their value before calling (#13)

* Add missing typehint

* Add missing typehint

* Add missing typehint

* Update dependencies

* Add badges and reorder intro docs

* Update dependencies

* Isolate bug #12

* Add support for 7.4 and 8.0

* Improve code quality

* Upgrade dependencies with PHP 8

Author: Greg Bowler

composer.lock

@@ -48,11 +48,25 @@ public function callOnRejected(Throwable $reason) {
 			$param = $reflection->getParameters()[0] ?? null;
 			if($param) {
 				$paramType = (string)$param->getType();
-				if(!strstr(
-					$error->getMessage(),
-					"must be of type $paramType"
-				)) {
-					throw $error;
+
+// TypeError messages behave slightly differently between PHP 7 and 8.
+// This strange if block will be dropped when PHP 7.4 support is dropped.
+				if(PHP_VERSION[0] >= 8) {
+					if(!strstr(
+						$error->getMessage(),
+						"must be of type $paramType"
+					)) {
+						throw $error;
+					}
+				}
+				else {
+					$paramType = str_replace("\\", "\\\\", $paramType);
+					if(!preg_match(
+						"/must be (of the type|an instance of) $paramType/",
+						$error->getMessage()
+					)) {
+						throw $error;
+					}
 				}
 			}
 

src/Chain/Chainable.php

@@ -19,7 +19,7 @@ class Promise implements PromiseInterface, HttpPromiseInterface {
 	private ?Throwable $rejection;
 	/** @var callable */
 	private $waitTask;
-	private float $waitTaskDelayMicroseconds;
+	private float $waitTaskDelay;
 
 	public function __construct(callable $executor) {
 		$this->state = HttpPromiseInterface::PENDING;
@@ -126,6 +126,14 @@ private function handleChain():void {
 				}
 				else {
 					$value = $then->callOnFulfilled($this->resolvedValue);
+					if($value instanceof PromiseInterface) {
+						$value->then(function($resolvedValue) {
+							$this->resolvedValue = $resolvedValue;
+							$this->complete();
+						});
+						break;
+					}
+
 					$this->state = HttpPromiseInterface::FULFILLED;
 					if(!is_null($value)) {
 						$this->resolvedValue = $value;
@@ -149,10 +157,10 @@ public function getState():string {
 
 	public function setWaitTask(
 		callable $task,
-		float $delayMicroseconds = 1_000
+		float $delaySeconds = 0.01
 	):void {
 		$this->waitTask = $task;
-		$this->waitTaskDelayMicroseconds = $delayMicroseconds;
+		$this->waitTaskDelay = $delaySeconds;
 	}
 
 	/** @param bool $unwrap */
@@ -163,7 +171,7 @@ public function wait($unwrap = true) {
 
 		while($this->getState() === HttpPromiseInterface::PENDING) {
 			call_user_func($this->waitTask);
-			usleep($this->waitTaskDelayMicroseconds);
+			usleep((int)($this->waitTaskDelay * 1_000_000));
 		}
 
 		$this->complete();

src/Promise.php

@@ -7,8 +7,8 @@ class PromiseResolvedWithAnotherPromiseException extends PromiseException {
 	const DEFAULT_MESSAGE = "A Promise must be resolved with a concrete value, not another Promise.";
 
 	public function __construct(
-		$message = self::DEFAULT_MESSAGE,
-		$code = 0,
+		string $message = self::DEFAULT_MESSAGE,
+		int $code = 0,
 		Throwable $previous = null
 	) {
 		parent::__construct($message, $code, $previous);

src/PromiseResolvedWithAnotherPromiseException.php

@@ -409,7 +409,12 @@ public function testMatchingTypedCatchRejectionHandlerCanHandleInternalTypeError
 		// should bubble out of the chain rather than being seen as
 		// missing the RangeException type hint.
 		self::expectException(TypeError::class);
-		self::expectExceptionMessage("DateTime::__construct(): Argument #1 (\$datetime) must be of type string, Closure given");
+		if(PHP_VERSION[0] >= 8) {
+			self::expectExceptionMessage("DateTime::__construct(): Argument #1 (\$datetime) must be of type string, Closure given");
+		}
+		else {
+			self::expectExceptionMessage("DateTime::__construct() expects parameter 1 to be string, object given");
+		}
 
 		$sut->catch(function(PromiseException $reason1) use($onRejected1) {
 			call_user_func($onRejected1, $reason1);
@@ -659,6 +664,28 @@ public function testWaitWithNoWaitTask() {
 		$sut->wait();
 	}
 
+	public function testFulfilledReturnsNewPromiseThatIsResolved() {
+		$numberPromiseContainer = $this->getTestPromiseContainer();
+		$numberPromise = $numberPromiseContainer->getPromise();
+
+		$messagePromiseContainer = $this->getTestPromiseContainer();
+		$messagePromise = $messagePromiseContainer->getPromise();
+
+		$numberToResolveWith = null;
+
+// The first onFulfilled takes the number to process, and returns a new promise
+// which should resolve to a message containing the number.
+		$numberPromise->then(function(int $number) use($messagePromiseContainer, $messagePromise, &$numberToResolveWith) {
+			$numberToResolveWith = $number;
+			return $messagePromise;
+		})->then(self::mockCallable(1, "Your number is 105"));
+
+// TODO: Issue #12: 105 resolves before the message does, so the numberPromise's then function will return a pending Promise.
+// The chained then should only be called after the message is resolved, so this needs to be stored internally somewhere for fulfillment.
+		$numberPromiseContainer->resolve(105);
+		$messagePromiseContainer->resolve("Your number is $numberToResolveWith");
+	}
+
 	protected function getTestPromiseContainer():TestPromiseContainer {
 		$resolveCallback = null;
 		$rejectCallback = null;