BUGFIX: Prevent flush force error in production context

[gjwnc]

What I did

The flow:cache:flush --force command runs Files::emptyDirectoryRecursively($environment->getPathToTemporaryDirectory()); which removes the lock file in the temporary directory too. The call to unlockSite() then causes a PHP warning because of the missing lock file.

Warning: unlink(/…/cbe856ff790c9ba5208811309bdf168b_Flow.lock): No such file or directory in /…/Core/LockManager.php line 145

This PR just add's a bit of error handling to the corresponding unlink of the lock file.

How to verify it

Run ./flow flow:cache:flush --force command in Production context.

Question

Since this is a bugfix, I used branch 6.3. In case of Flow 7, some PHP 8 compatiblity was added which would change the PR to

            try {
                @unlink($this->lockPathAndFilename);
            } catch (\Throwable $e) {
                // PHP 8 apparently throws for unlink even with shutup operator, but we really don't care at this place. It's also the only way to handle this race-condition free.
            }

Should I create another PR if this one is merged to get PHP 8 compatibility?

Checklist

• Code follows the PSR-2 coding style
• Tests have been created, run and adjusted as needed
• The PR is created against the lowest maintained branch

[albe]

Should I create another PR if this one is merged to get PHP 8 compatibility?

Yes, that would be the way to go.

[kdambekalns]

Bah, the shut-up operator… But I checked, and despite not wanting to use it, we do use it in 30 places within our actual code. So, let's add one more. ;)

[kdambekalns]

Ignored the Psalm error, as they are clearly unrelated.

[gjwnc]

@albe @kdambekalns I've created a new PR regarding PHP 8 compatiblity - see #2795