Important: FlexForm paths change for the plugin structures

Description

The FlexForm data structures of the plugins have moved. Compared with the last 2.x release, the folder layout of EXT:academic_persons/Configuration/FlexForms/ is now:

Structure	In 2.3.4	In 3.0.0
`List.xml`, `Detail.xml`	`Core12/`, `Core13/`	`Core13/`, `Core14/`
`SelectedProfiles.xml`, `SelectedContracts.xml`	`Core12/`, `Core13/`	directly in `FlexForms/`

The Core12/ variants are gone with TYPO3 v12 support. SelectedProfiles.xml and SelectedContracts.xml are identical on every supported version and are no longer duplicated. List.xml and Detail.xml keep their Core13/ path and gain a Core14/ sibling.

Those two still need a variant per version because of settings.pageTitleFormat, the only field in this extension configured with a valuePicker. TYPO3 changed how it reads the items of that picker, and it is the one item list core never made readable in both directions:

TYPO3	Reads	Given the other form
v13	the positional pair `$item[0]` / `$item[1]`	`Undefined array key 1`, then a `TypeError` - the element renders nothing and the plugin cannot be opened
v14	`$item['label']` / `$item['value']`	migrated on the fly, at the price of an `E_USER_DEPRECATED`

FlexForm XML cannot carry a runtime switch, so the two forms need two files. Configuration/TCA/Overrides/tt_content.php selects the folder from the running major version.

Impact

Nothing changes for a site that installs the extension and configures its plugins in the backend. The plugin options are the same on both TYPO3 versions.

Affected Installations

Installations that reference one of the four data structures by path - for example an extension or site package that registers the same structure for a content element of its own, or overrides it through $GLOBALS['TCA']['tt_content']['columns']['pi_flexform']['config']['ds'].

References to Core12/… and to Core13/SelectedProfiles.xml or Core13/SelectedContracts.xml no longer resolve. References to Core13/List.xml and Core13/Detail.xml keep working, but only deliver the TYPO3 v13 variant.

Solution

Reference the two shared structures directly:

FILE:EXT:academic_persons/Configuration/FlexForms/SelectedProfiles.xml
FILE:EXT:academic_persons/Configuration/FlexForms/SelectedContracts.xml

For the two split ones, select the variant that matches the running TYPO3 version, the way this extension does:

EXT:my_extension/Configuration/TCA/Overrides/tt_content.php

use TYPO3\CMS\Core\Information\Typo3Version;

$flexFormPath = 'FILE:EXT:academic_persons/Configuration/FlexForms/'
    . ((new Typo3Version())->getMajorVersion() < 14 ? 'Core13' : 'Core14')
    . '/';

// $flexFormPath . 'List.xml'
// $flexFormPath . 'Detail.xml'

Once support for TYPO3 v13 is dropped, the Core13 variants go away and the Core14 ones move back up one level.