Breaking: #88564 - PageTSconfig setting "TSFE.constants" removed

See forge#88564

Description

The PageTSconfig / UserTSconfig TSFE.constants, which allowed to override settings constants on a per-tree level page was introduced in TYPO3 at the very beginning, long before TSconfig had conditions.

It was used to share TypoScript-based configuration between frontend / backend, and on a per-page/tree level.

However, this has been superseded for a long time by using proper configuration files which can be loaded at any time, for example when ext_localconf.php of an extension is loaded.

Therefore, the option has been removed.

Impact

Setting TSFE.constants in PageTSconfig or UserTSconfig has no effect, as it is not evaluated anymore.

Affected Installations

Any TYPO3 installation using TSFE.constants in their PageTSconfig.

Migration

It is recommended to include TypoScript conditions in setup/constants, also since constants+setup are evaluated in Backend context for Extbase modules. This option is not needed anymore and can be substituted by simple constants in sys_template or any Extension inclusion files as well.