Fix STDERR pollution corrupting exception serialization + silent exception swallowing

src/Process/ParallelProcess.php

@@ -87,6 +87,13 @@ public function getErrorOutput()
         if (! $this->errorOutput) {
             $processOutput = $this->process->getErrorOutput();
 
+            $marker = '___SPATIE_ASYNC_CHILD___';
+            $markerPosition = strrpos($processOutput, $marker);
+
+            if ($markerPosition !== false) {
+                $processOutput = substr($processOutput, $markerPosition + strlen($marker));
+            }
+
             $childResult = @unserialize(base64_decode($processOutput));
 
             if ($childResult === false || ! array_key_exists('output', $childResult)) {

src/Process/ProcessCallbacks.php

@@ -64,8 +64,10 @@ public function triggerError()
 
             call_user_func_array($callback, [$exception]);
 
-            break;
+            return;
         }
+
+        throw $exception;
     }
 
     abstract protected function resolveErrorOutput(): Throwable;

src/Runtime/ChildRuntime.php

@@ -51,7 +51,7 @@
 
     $output = new \Spatie\Async\Output\SerializableException($exception);
 
-    fwrite(STDERR, base64_encode(serialize(['output' => $output])));
+    fwrite(STDERR, '___SPATIE_ASYNC_CHILD___'.base64_encode(serialize(['output' => $output])));
 
     exit(1);
 }

tests/Feature/ErrorHandlingTest.php

@@ -185,6 +185,37 @@
     expect($caughtError)->toBeInstanceOf(ParseError::class);
 });
 
+it('preserves exception type when stderr contains noise', function () {
+    $pool = Pool::create();
+
+    $caughtException = null;
+
+    $pool->add(childTask(function () {
+        trigger_error('some deprecation notice', E_USER_WARNING);
+
+        throw new MyException('test');
+    }))->catch(function (MyException $e) use (&$caughtException) {
+        $caughtException = $e;
+    });
+
+    $pool->wait();
+
+    expect($caughtException)->toBeInstanceOf(MyException::class);
+    expect($caughtException->getMessage())->toContain('test');
+});
+
+it('throws exception when no catch handler matches', function () {
+    $pool = Pool::create();
+
+    $pool->add(childTask(function () {
+        throw new MyException('test');
+    }))->catch(function (OtherException $e) {
+        // This handler should not match
+    });
+
+    $pool->wait();
+})->throws(MyException::class);
+
 it('can handle synchronous exception', function () {
     Pool::$forceSynchronous = true;
 

tests/Feature/PoolTest.php

@@ -336,7 +336,9 @@
     $cntTasks = 30;
 
     foreach (range(1, $cntTasks) as $i) {
-        $pool->add(childTask(function () { return 1; }));
+        $pool->add(childTask(function () {
+            return 1;
+        }));
     }
 
     $pool->wait();