LocalFilesystemAdapter. Call clearstatcache in several methods

[pvandommelen]

Php's statcache caches the results of some file functions like is_file or filesize.

For the visibility() method, a clearstatcache is already used to clear this cache, but this is not the case for several other methods.

Fixes #1826

[frankdejonge]

Can you add a configuration option to opt-in to this behaviour?

[pvandommelen]

Thanks for the quick reply! Do we really have to have a configuration option for this?

clearstatcache is already used in the visibility method, which would probably also be affected by such an option. Something similar is also implemented in ensureDirectoryExists.

As mentioned in the issue, this commit would mostly reapply an older fix (6f2211c). Though that's on a much older release.

If you'd still like a configuration option, I can add one. But I think we should then move the existing clearstatcache calls behind that check.

[shyim]

Would you merge an PR to make this opt-in @frankdejonge?

This change makes stat-cache useless, and tbh when you call exec, the caller should clear stat-cache not the filesystem abstraction on EVERYTHING 😅

[frankdejonge]

@shyim hi, yes that would work! 👍

[pvandommelen]

No objections from my side to make it configurable.

I would maybe consider this option being opt-out instead of opt-in. Mostly because having no caching would be a reasonable default and there have even been calls to remove the statcache in php itself entirely (https://externals.io/message/115912).

Just to clarify our use case since it is different from the one in the related issue (calling exec). We run a file exists check in a while loop as a low-tech method to detect the status of an external process. For this it is important that there is no cache involved.