TYPO3 Core

When fetching the TS configuration of a page in Backend context by utilizing the ConfigurationManager, sys_template entries in the rootline are loaded, even when they are hidden.

I stumbled across this because I had a hidden sys_template with sys_template.clear >0 in the rootline which prevented my site set TS from being loaded. After completely deleting the entry, the site set TS was loaded.

How to reproduce

Requirements
- fresh TYPO3 v13.4 installation
- a hidden sys_template placed on the root page with dummy TS setup
- a Backend Controller with the following code (tested within a class that extends the StandardContentPreviewRenderer)

$configurationManager = GeneralUtility::makeInstance(ConfigurationManager::class);
$configuration = $configurationManager->getConfiguration(ConfigurationManagerInterface::CONFIGURATION_TYPE_FULL_TYPOSCRIPT);

- optional: a site set dependency in the site config, which contains a setup.typoscript with dummy TS

When you debug $configuration on any page below the root page (or itself), you can see that the TS setup of the hidden sys_template is loaded by the ConfigurationManager. Having sys_template.clear >0, even prevents the site set from being loaded. After deleting the sys_template record completely, the site set TS setup is loaded again.