unable to use theme as form entry id

[oiseauroch]

Description

using keyword like theme, squelette, style and preset for checkbox field id give 502 when trying to save form entry.

How to reproduce

• Create a form with checkbox from list
• use theme as id
• try to create new entry with some theme selected

Logs : 

thrown in /var/www/yeswiki/includes/services/ThemeManager.php on line 128" while reading response header from upstream, client: 192.168.0.1, server: domain.tld, request: "POST /?BazaR&vue=saisir&action=saisir_fiche&id=5 HTTP/1.1", upstream: "fastcgi://unix:/var/run/php/php8.2-fpm.sock:", host: "domain.tld", referrer: "https://domain.tld/?BazaR&vue=saisir&action=saisir_fiche&id=5"
2025/10/01 09:26:17 [error] 1656466#1656466: *397244 FastCGI sent in stderr: "PHP message: PHP Fatal error:  Uncaught TypeError: preg_match(): Argument #2 ($subject) must be of type string, array given in /var/www/yeswiki/includes/services/ThemeManager.php:128

It seems that theme, squelette, style and preset are reserved keywords and should not allowed to be used as form field id.

[mrflos]

interesting! in fact ThemeManager is catching all $_REQUEST vars..
Probably keywords like action or template in bazar context could also break things..
I don't know if I should verify the context where they are used or reserve a certain amount of keywords (probably the second option is easier).