Require exact match when reading from stdin with a dash

Author: nicolas-grekas

Command/LintCommand.php

@@ -86,9 +86,9 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $this->format = $input->getOption('format');
         $this->displayCorrectFiles = $output->isVerbose();
         $flags = $input->getOption('parse-tags') ? Yaml::PARSE_CUSTOM_TAGS : 0;
-        $hasStdin = '-' === ($filenames[0] ?? '');
+        $hasStdin = ['-'] === $filenames;
 
-        if ($hasStdin || 0 === \count($filenames)) {
+        if ($hasStdin || !$filenames) {
             if (!$hasStdin && 0 !== ftell(STDIN)) { // remove 0 !== ftell(STDIN) check in 5.0
                 throw new RuntimeException('Please provide a filename or pipe file content to STDIN.');
             }