After Upgrade PHP to 8.1 version - flock(): supplied resource is not a valid stream resource

Question

I have Magento v2.4.5-p1 and after php version upgrade to 8.1 when running the command: index:reindex i get this error for each index: flock(): supplied resource is not a valid stream resource.

Has anyone experienced this? How can I fix it?

Answer 1

I found a solution. Like this solution I have a third party extension that was causing me to get the error. Adding validation helped solve the problem.

As it was:

        @flock($pointer, LOCK_UN);
        @fclose($pointer);

My fix:

    if (is_resource($pointer) && get_resource_type($pointer) == 'stream') {
        @flock($pointer, LOCK_UN);
        @fclose($pointer);
    }