卷子生成pdf效果制作

app/Services/ExamPdfExportService.php

@@ -130,7 +130,7 @@ class ExamPdfExportService
 
         if (!$process->isSuccessful() || !file_exists($tmpPdf)) {
             Log::error('ExamPdfExportService: Chrome 渲染失败', [
-                'cmd' => implode(' ', $process->getCommandLine()),
+                'cmd' => implode(' ', (array) $process->getCommandLine()),
                 'exit_code' => $process->getExitCode(),
                 'error' => $process->getErrorOutput(),
                 'output' => $process->getOutput(),