Breaking: #66001 - Third-party libraries installed via composer are now in vendor

See Issue #66001

Description

All composer-installed libraries which the TYPO3 Core uses are now installed under vendor (composer default vendor directory) when running composer install . This way the packaging process for releasing TYPO3 CMS as tarball or zip can trigger a fully working installation without having to ship Packages/ for third-party libraries. Before composer installed all third-party libraries in the folder Packages/Libraries .

Impact

Any existing installation that is set up via composer based on the composer.json of the TYPO3.CMS.git repository will break if Unit Tests or Functional Tests via bin/phpunit will fail unless composer dependencies have been completely rebuilt.

Affected installations

Installations using a Packages/ directory within the typo3_src/ folder structure, most commonly by having checked out the TYPO3.CMS.git Repository and having run composer install after that. Any installations using the common TYPO3 distribution from composer.typo3.org are not affected.

Migration

Running rm -rf vendor/ bin/ Packages/Libraries/ composer.lock; composer install will make PHPunit work again.