Feature: #78169 - Introduce "Translation Source" field for tt_content 

See forge#78169

Description 

The new database field l10n_source for tt_content table has been introduced together with a new TCA ctrl configuration translationSource. The translationSource field contains a uid of the record used as a translation source, no matter whether the record was translated in the free or connected mode. The new TCA configuration translationSource contains column name, similar to the transOrigPointerField. e.g.

$GLOBALS['TCA']['tt_content']['ctrl']['translationSource'] = 'l10n_source';
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The new field solves few issues:

  1. There was no way to detect whether a record was translated using connected mode or free mode. If a record has value > 0 in the transOrigPointerField (e.g. l10n_parent) field, it means it was translated using "connected mode". If the transOrigPointerField is 0 but the translationSource field is > 0 it means it was translated using "free mode". If both are 0, it means the record was not translated but created manually.
  2. TYPO3 allows to use a record in non-default language as a translation source. In this case the information about the translation source was lost. Now, the translationSource field always contains a uid of the record used as a translation source.
  3. In some places origUid (e.g. t3_origuid) fields were misused as a translation source. Now these places can be refactored to use the translationSource field.

Difference between translationSource and other existing fields 

  1. transOrigPointerField (e.g. l10n_parent) - "translation parent" - this field contains uid of the record in the default language representing the same content. The translationSource field can contain a uid of the record in non-default language.
  2. origUid (e.g. t3_origuid) - "copy source" - this field contains uid of the record, current record was copied from. It might be equal to translationSource as localization is a copy internally, but often it is different.

See following test scenarios to see how data is handled in details.

  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::localizeContent
  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::localizeContentFromNonDefaultLanguage
  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::copyContentToLanguage
  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::copyPage
  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::copyPageFreeMode
  • \TYPO3\CMS\Core\Tests\Functional\DataHandling\Regular\Modify\ActionTest::localizePage

Impact 

Introduction of the new field is a base step for further refactorings, e.g.

  • it opens a way to implement features like "reconnecting" free-mode translations back to the "connected mode"
  • replace usage of the t3_origuid with the l10n_source where t3_origuid is misused for language handling purposes (e.g. in LocalizationRepository)