Breaking: #80149 - Remove $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields']

See Issue #80149

Description

The configuration $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields'] is removed from the default configuration as well as from the overlay handling in PageRepository and RootlineUtility.

This setting has been used to determine overlay fields in the table :sql:`pages_language_overlay` at a time in the runtime processing when the complete TCA was not fully available. Since the allowLanguageSynchronization possibility has been integrated into TYPO3 CMS 8, l10n_mode was available already and the TCA is loaded as well, the pageOverlayFields settings are superfluous.

Impact

Since $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields'] was used as a filter for field names to be taken from :sql:`pages_language_overlay` and merged onto those fields in :sql:`pages`, all fields are overlaid per default.

Affected Installations

All installations having custom fields in table :sql:`pages_language_overlay` and custom settings in $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields'].

Migration

Check the TCA of :sql:`pages_language_overlay` and remove l10n_mode for those fields that previously were not defined in $GLOBALS['TYPO3_CONF_VARS']['FE']['pageOverlayFields']

and thus should not be overlaid.