Breaking: #88525 - Remove "createDirs" directive of extension installation / em_conf.php

See forge#88525

Description

Every TYPO3 extension has a file called :file`ext_emconf.php` where important information regarding dependencies, current version and loading order are stored.

The directive createDirs that was responsible to create a list of folders in the file structure during extension installation has been dropped.

The option was available before any File Abstraction Layer. As the uploads/ folder is not created by default by TYPO3 anymore, this directive is not supported anymore as well, as TYPO3 strives to support unified file handling for content files, volatile files (file uploads within typo3temp/var/) or within Extensions directly. The Environment API, introduced in TYPO3 v9, should support for PHP-based APIs to choose / create a correct folder location.

Impact

Extensions having this directive set will not have this folder available at installation time of the extension. The folder will not be created for newly installed extensions, existing extensions when upgrading from previous TYPO3 versions, will continue to exist.

Affected Installations

Any TYPO3 extension having this property within ext_emconf.php set.

Migration

When an extension supports TYPO3 v10+ only, this directive can be removed.

If an extension needs a special directory, this should be created via PHP when it is needed via e.g. GeneralUtility::mkdir_deep().