fix: handle stdio properly

src/Child.php

@@ -19,31 +19,55 @@ final class Child
 
     public function id(): int
     {
+        if (!is_resource($this->proc)) {
+            throw new ChildException('Resource was already closed');
+        }
+
         $status = proc_get_status($this->proc);
         return $status['pid'];
     }
 
-    public function output(): Output
+    public function waitWithOutput(): Output
     {
+        if (!is_resource($this->proc)) {
+            throw new ChildException('Resource was already closed');
+        }
+
+        // Avoid possible deadlock before waiting.
+        $this->stdin?->close();
+
         $stdout = $this->stdout?->getContents();
         $stderr = $this->stderr?->getContents();
-        $code = proc_close($this->proc);
+        $status = new ExitStatus(proc_close($this->proc));
 
-        return new Output($stdout, $stderr, $code);
+        return new Output($stdout, $stderr, $status);
     }
 
-    public function status(): int
+    public function wait(): ExitStatus
     {
-        return proc_close($this->proc);
-    }
+        if (!is_resource($this->proc)) {
+            throw new ChildException('Resource was already closed');
+        }
 
-    public function wait(): void
-    {
-        proc_close($this->proc);
+        // Avoid possible deadlock before waiting.
+        $this->stdin?->close();
+
+        return new ExitStatus(proc_close($this->proc));
     }
 
     public function kill(): bool
     {
+        if (!is_resource($this->proc)) {
+            throw new ChildException('Resource was already closed');
+        }
+
         return proc_terminate($this->proc, 10);
     }
+
+    public function __destruct()
+    {
+        if (is_resource($this->proc)) {
+            proc_close($this->proc);
+        }
+    }
 }