QA - pcntl_exec - check stringable parameters error

Closes GH-8990.

Author: juan-morales

ext/pcntl/tests/pcntl_exec_004.phpt

@@ -0,0 +1,25 @@
+--TEST--
+pcntl_exec() - Testing error when non-stringable arguments are passed for $args and $env_vars.
+--EXTENSIONS--
+pcntl
+--SKIPIF--
+<?php
+if (!getenv("TEST_PHP_EXECUTABLE") || !is_executable(getenv("TEST_PHP_EXECUTABLE"))) die("skip TEST_PHP_EXECUTABLE not set");
+?>
+--FILE--
+<?php
+try {
+    pcntl_exec(getenv("TEST_PHP_EXECUTABLE"), ['-n', new stdClass()]);
+} catch (Error $error) {
+    echo $error->getMessage() . "\n";
+}
+
+try {
+    pcntl_exec(getenv("TEST_PHP_EXECUTABLE"), ['-n'], [new stdClass()]);
+} catch (Error $error) {
+    echo $error->getMessage() . "\n";
+}
+?>
+--EXPECT--
+Object of class stdClass could not be converted to string
+Object of class stdClass could not be converted to string