Path filter does not allow dots at the beginning of folders / files names

[n3t]

Paths with dots at the beginning of folder or file name doesn't pass current path filter regular expressions. For example /var/www/.secret doesn't pass, even it is valid path. This influence Joomla CMS update system, when used such path for global temp dir.

Steps to reproduce the issue

Set in Joomla global configuration Temp path with hidden folder (starting with dot), for example /var/www/.tmp.
Go to Joomla update component and try to download and install update.

Expected result

No error, update is installed.

Actual result

Error is displayed, update is not installed.

System information (as much as possible)

Joomla CMS with Joomla Filter 1.4.3

Additional comments

This is B/C break in Joomla CMS, as it influence Joomla update system. Path doesn't pass filter, so returns empty string, which causes updater to fail download update file, with incorrect error message.

Tried to solve it in joomla/joomla-cms#33151, which was incorrect, as I was noticed of double dots folders (and also PR to wrong project :))

[n3t]

No comment on this? Currently this issue makes one of my websites unupdateable. The web root path contains @, which causes Joomla updater to fail. No way to influence this, this is hosting settings.