support session.save_path in N;MODE;/path format

[tenzap]

While deploying a project based on CI3 on sourceforge.net web servers, I faced a problem with session save path.

sourceforge.net's web servers run PHP 7.1 and are configured with session.save_path set to 3;600;/home/web-sessions

In the config.php of the CI3 project we left the value to the default NULL so it takes the value of php.ini's session.save_path.

But with the config set to 3;600;/home/web-sessions PHP returns this error:

Fatal error: session_start(): Failed to initialize storage module: user (path: 3;600;/home/web-sessions) in ....

Note: This type of configuration is described here: https://www.php.net/manual/en/session.configuration.php#ini.session.save-path

Error is on this line:

CodeIgniter/system/libraries/Session/Session.php

Line 137 in bcb17eb

session_start();

And here we have a check if the session_save_path is a dir is_dir() which doesn't pass. Hence the error.
https://github.com/bcit-ci/CodeIgniter/blob/3.1.13/system/libraries/Session/drivers/Session_files_driver.php#L133

Could this type of configuration be supported in future? Or maybe also in CI4?

Workaround: create a custom folder and settthe path to it in config.php. However it would probably be better to use the built-in config on sourceforge which may be optimized and have some GC, which can't be done/configured in the project webspace.