use of special characters(^ and $) in INI setting for type string won't work as expected

[HeenaBansal2009]

Description

The ini setting doesn't work as expected when setting has regex expressions
My customized ini file has string with regular expressions like below
Case 1:
Ini setting value :
abc=[Tt][Oo][Kk][Ee][Nn].,^[Qq],one, two

php -I |grep abc shows
myextension.abc=> 0 => 0

But I expected this output instead:
php -I |grep abc shows
myextension.abc=> [Tt][Oo][Kk][Ee][Nn].,^[Qq],one, two =>[Tt][Oo][Kk][Ee][Nn].,^[Qq],one, two

Case 2:
Ini setting value :
abc=[Tt][Oo][Kk][Ee][Nn].

php -I |grep abc shows
myextension.abc=> [Tt][Oo][Kk][Ee][Nn].=>[Tt][Oo][Kk][Ee][Nn].

Case 3:
Ini setting value :
abc=.^[Qq]$
php -I |grep abc shows
PHP: syntax error, unexpected '=' myextension.ini on line 9
myextension.abc=> 0 =>0

Is there any limitation with regex expressions in php ini settings. Though It seems like carrot ^ and $ dollar sign doesn't seems to work with string ini setting.

PHP Version

PHP 8.1

Operating System

No response

[damianwadley]

PHP understands some special characters in INI files. ^ is one of them, and acts as an XOR operator; it's meant to be used with bitmask fields like error_reporting. $ is another, in that can be used for interpolating variables and so gets its own treatment during parsing.

If you want special characters like those then the value needs to be quoted.

abc="[Tt][Oo][Kk][Ee][Nn].,^[Qq],one, two"

If you need a " itself, escape it with a backslash.

https://www.php.net/manual/en/configuration.file.php
https://www.php.net/manual/en/function.parse-ini-file.php (which is what PHP uses internally too)