TYPO3 Core

On copying a sys_category record, a new MM reference is created, however without setting the "fieldname".
This value is basically defined from the opposite entity with MM_match_fields, but cannot be accessed.

This change introduces the MM_oppositeUsage property for MM definitions in the TCA.

Example:

...
'allowed' => '*',
'MM' => 'tx_myextension_first_second_mm',
'MM_oppositeUsage' => array(
'tt_content' => array('somefield'),
'tx_myextension_domain_model' => array('some_property'),
),
...