[Process] Fix Inconsistent Exit Status in proc_get_status for PHP Versions Below 8.3

Author: Luc45

Process.php

@@ -80,6 +80,7 @@ class Process implements \IteratorAggregate
     private $processPipes;
 
     private $latestSignal;
+    private $cachedExitCode;
 
     private static $sigchild;
 
@@ -1345,6 +1346,19 @@ protected function updateStatus(bool $blocking)
         $this->processInformation = proc_get_status($this->process);
         $running = $this->processInformation['running'];
 
+        // In PHP < 8.3, "proc_get_status" only returns the correct exit status on the first call.
+        // Subsequent calls return -1 as the process is discarded. This workaround caches the first
+        // retrieved exit status for consistent results in later calls, mimicking PHP 8.3 behavior.
+        if (\PHP_VERSION_ID < 80300) {
+            if (!isset($this->cachedExitCode) && !$running && -1 !== $this->processInformation['exitcode']) {
+                $this->cachedExitCode = $this->processInformation['exitcode'];
+            }
+
+            if (isset($this->cachedExitCode) && !$running && -1 === $this->processInformation['exitcode']) {
+                $this->processInformation['exitcode'] = $this->cachedExitCode;
+            }
+        }
+
         $this->readPipes($running && $blocking, '\\' !== \DIRECTORY_SEPARATOR || !$running);
 
         if ($this->fallbackStatus && $this->isSigchildEnabled()) {

Tests/ProcessTest.php

@@ -1541,6 +1541,60 @@ public function testEnvCaseInsensitiveOnWindows()
         }
     }
 
+    public function testMultipleCallsToProcGetStatus()
+    {
+        $process = $this->getProcess('echo foo');
+        $process->start(static function () use ($process) {
+            return $process->isRunning();
+        });
+        while ($process->isRunning()) {
+            usleep(1000);
+        }
+        $this->assertSame(0, $process->getExitCode());
+    }
+
+    public function testFailingProcessWithMultipleCallsToProcGetStatus()
+    {
+        $process = $this->getProcess('exit 123');
+        $process->start(static function () use ($process) {
+            return $process->isRunning();
+        });
+        while ($process->isRunning()) {
+            usleep(1000);
+        }
+        $this->assertSame(123, $process->getExitCode());
+    }
+
+    /**
+     * @group slow
+     */
+    public function testLongRunningProcessWithMultipleCallsToProcGetStatus()
+    {
+        $process = $this->getProcess('php -r "sleep(1); echo \'done\';"');
+        $process->start(static function () use ($process) {
+            return $process->isRunning();
+        });
+        while ($process->isRunning()) {
+            usleep(1000);
+        }
+        $this->assertSame(0, $process->getExitCode());
+    }
+
+    /**
+     * @group slow
+     */
+    public function testLongRunningProcessWithMultipleCallsToProcGetStatusError()
+    {
+        $process = $this->getProcess('php -r "sleep(1); echo \'failure\'; exit(123);"');
+        $process->start(static function () use ($process) {
+            return $process->isRunning();
+        });
+        while ($process->isRunning()) {
+            usleep(1000);
+        }
+        $this->assertSame(123, $process->getExitCode());
+    }
+
     /**
      * @group transient-on-windows
      */
@@ -1556,7 +1610,6 @@ public function testNotTerminableInputPipe()
 
     /**
      * @param string|array $commandline
-     * @param mixed        $input
      */
     private function getProcess($commandline, ?string $cwd = null, ?array $env = null, $input = null, ?int $timeout = 60): Process
     {