Skip cancellation of promise within Fiber without cancellation support

src/FiberMap.php

@@ -25,7 +25,7 @@ public static function cancel(\Fiber $fiber): void
 
     public static function isCancelled(\Fiber $fiber): bool
     {
-        return self::$status[\spl_object_id($fiber)];
+        return self::$status[\spl_object_id($fiber)] ?? false;
     }
 
     public static function setPromise(\Fiber $fiber, PromiseInterface $promise): void

tests/AwaitTest.php

@@ -97,6 +97,27 @@ public function testAwaitAsyncThrowsExceptionImmediatelyWhenPromiseIsRejected(ca
         }
     }
 
+    /**
+     * @dataProvider provideAwaiters
+     */
+    public function testAwaitThrowsExceptionImmediatelyInCustomFiberWhenPromiseIsRejected(callable $await)
+    {
+        $fiber = new \Fiber(function () use ($await) {
+            $promise = new Promise(function ($resolve) {
+                throw new \RuntimeException('Test');
+            });
+
+            return $await($promise);
+        });
+
+        try {
+            $fiber->start();
+        } catch (\RuntimeException $e) {
+            $this->assertTrue($fiber->isTerminated());
+            $this->assertEquals('Test', $e->getMessage());
+        }
+    }
+
     /**
      * @dataProvider provideAwaiters
      */
@@ -230,6 +251,25 @@ public function testAwaitAsyncReturnsValueImmediatelyWhenPromiseIsFulfilled(call
         $this->assertEquals(1, $ticks);
     }
 
+    /**
+     * @dataProvider provideAwaiters
+     */
+    public function testAwaitReturnsValueImmediatelyInCustomFiberWhenPromiseIsFulfilled(callable $await)
+    {
+        $fiber = new \Fiber(function () use ($await) {
+            $promise = new Promise(function ($resolve) {
+                $resolve(42);
+            });
+
+            return $await($promise);
+        });
+
+        $fiber->start();
+
+        $this->assertTrue($fiber->isTerminated());
+        $this->assertEquals(42, $fiber->getReturn());
+    }
+
     /**
      * @dataProvider provideAwaiters
      */