I'm curious about the initial intent for this check. I think it's still a requirement for a plugin to have a readme.txt file, even if it also includes a readme.md, since the header in the txt version is the one used for parsing out plugin info like version, tested up to, etc.

See: https://developer.wordpress.org/plugins/wordpress-org/how-your-readme-txt-works/#readme-header-information

@joemcgill I thought so too, but someone else (I don't recall, maybe it was @swissspidy or @westonruter?) pointed out that wordpress.org, despite not well documenting it, actually supports using readme.md as well as the actual .org readme file. So if you don't include readme.txt but include readme.md, wordpress.org will try to parse its contents apparently. Of course that only works if you format readme.md correctly for that purpose, not if it's a general readme e.g. for just GitHub.

I thought so too, but someone else (I don't recall, maybe it was @swissspidy or @westonruter?) pointed out that wordpress.org

I think it was actually @johnbillion: https://johnblackbourn.com/readme-md-plugin-on-wordpress-org/

For the AMP plugin we initially tried just going with README.md alone in ampproject/amp-wp#5807, but in ampproject/amp-wp#5815 we re-introduced the readme.txt but created it at build time out of the README.md due to various WordPress-specific issues with the format.

That's really interesting, I didn't realize this was supported. Still, I'm curious if the lack of a README.txt file would get flagged in the plugin review process, and if so, is something we should still include as a check in our plugin?

I don't think we need to specifically check for readme.txt, as either works. This is also confirmed by the other plugin checker code, which supports either file extension in the same way: https://github.com/WordPress/plugin-check/blob/trunk/plugin.php#L76

Thanks all the the review and details. The PR is ready for review.

The Plugin Checker currently checks all files, including in subfolders. However, we should modify the check to only consider files in the root directory for readme.txt and readme.md checks.

WordPress allows and parse readme.txt and readme.md files in root directory of the plugin. Therefore, we will adjust the Plugin Checker accordingly to focus only on root directory files.

For instance, when we checked the WooCommerce plugin, the Plugin Checker returned an array of files as follows:

/var/www/html/wp-content/plugins/woocommerce/Array
(
    [1511] => /var/www/html/wp-content/plugins/woocommerce/packages/action-scheduler/readme.txt
    [1668] => /var/www/html/wp-content/plugins/woocommerce/packages/woocommerce-blocks/assets/js/base/README.MD
    [3531] => /var/www/html/wp-content/plugins/woocommerce/packages/woocommerce-blocks/readme.txt
    [3962] => /var/www/html/wp-content/plugins/woocommerce/readme.txt
)

The specific error highlighted was:

FILE: packages/action-scheduler/readme.txt

We will update the Plugin Checker to only report errors for readme.txt and readme.md files that are directly in the root directory of the plugin and not in subfolders.

@felixarntz @joemcgill If the above makes sense, then I will open the follow-up issue and start working on it. Thanks.

Thanks @mukeshpanchal27, that's a great catch! +1 to opening a follow-up issue and PR to fix it so that the plugin checker only considers readme files in the root directory.