Breaking: #75454 - TYPO3_db Constants removed

See Issue #75454

Description

The PHP constants TYPO3_db, TYPO3_db_username, TYPO3_db_password and TYPO3_db_host which were used when TYPO3 initialized the database connection have been removed.

Impact

Checking for or using the mentioned constants may lead to unexpected behavior or errors. If not checked if the constant even was defined, the application will stop immediately.

Affected Installations

Any installation which uses a third-party extension using these constants.

Migration

Use the configuration data within $GLOBALS['TYPO3_CONF_VARS']['DB']['Connections']['Default'] to determine the username, password and host information for the default database connection.