Fix "Nextcloud is not allowed to use the OPcache API" warning

[knox]

This aims to fix "Nextcloud is not allowed to use the OPcache API" warning being displayed even though OPcache is configured and running fine.

With the latest update to 23 the above warning appeared but there were no warnings or any issues before the update.

So i dug into this and found the string comparison to be causing the warning: in my setup opcache.restrict_api has a trailing slash whereas OC::$SERVEROOT has not. 🙈

To be honest i wasn't sure wether to add a slash to the server root for comparison or to remove the trailing slash and in the end i decided for the latter. Also please note that i'm not an every day PHP developer at all so don't mind if this attempt of solving the issue is not the right way to fix it at all. I'm just trying to follow the idea of submitting patches instead of just filing bugs and it was quite interesting to read through all of this. 😉

Why is there a trailing slash in my opcache.restrict_api and why dont i just remove it? I'm running a self-hosted Nextcloud instance on a server that is otherwise managed using Froxlor Server Management Panel. With this management panel the opcache.restrict_api gets somewhat dynamically configured per virtual host using a placeholder {DOCUMENT_ROOT} wich in turn has this trailing slash.

[knox]

@MichaIng would you please have a look here? 👍

[MichaIng]

Many thanks, looks good. Makes sense to not break only because of a trailing slash 👍.

[MichaIng]

/backport to stable23

[welcome]

Thanks for your first pull request and welcome to the community! Feel free to keep them coming! If you are looking for issues to tackle then have a look at this selection: https://github.com/nextcloud/server/issues?q=is%3Aopen+is%3Aissue+label%3A%22good+first+issue%22

[xbluemonkx]

Hi, I just updated to 23.0.3, but I am still seeing the error message in the admin panel: "The PHP OPcache module is not properly configured" - even everything is set up properly.

[MichaIng]

This only fixes the case where one is using something like opcache.restrict_api=/var/www/nextcloud/. If your warning does not contain "Nextcloud is not allowed to use the OPcache API" while you are sure you correctly configured opcache.restrict_api (or did not configure it at all), then your issue is unrelated, or the recommendation you see is simply correct and you may follow it.