[bug] container ignores creationOptions if only 1 contentElementType is allowed

[thomasrawiel]

Summary

When a container allows only 1 specific content element type, its creationOptions are ignored when adding it to the container.
TYPO3 13: defaultValues, saveAndClose
TYPO3 14: additionally enableDirectRecordTypeCreation, title

creationOptions in TYPO3 docs

Example code

$GLOBALS['TCA']['tt_content']['types']['header']['creationOptions']['defaultValues'] = ['sectionIndex'=>0, 'header'=>'Example header', 'header_layout'=>5];

\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(\B13\Container\Tca\Registry::class)->configureContainer(
    (
    new \B13\Container\Tca\ContainerConfiguration(
        'b13-2cols-with-header-container', // CType
        '2 Column Container With Header', // label
        'Some Description of the Container', // description
        [
            [
                ['name' => 'header', 'colPos' => 200, 'colspan' => 2, 'allowed' => ['CType' => 'header']]
            ],
            [
                ['name' => 'left side', 'colPos' => 201],
                ['name' => 'right side', 'colPos' => 202]
            ]
        ] // grid configuration
    )
    )
        // set an optional icon configuration
        ->setIcon('EXT:container_example/Resources/Public/Icons/b13-2cols-with-header-container.svg')
);

Adds creation Options to the header CType.
Adds a container with a header column, where only the header CType is allowed.

Adding content to the header column selects the correct CType, but ignores the creationOptions/ defaultValues

Cause

B13\Container\Backend\Preview\GridRenderer::getDefValsForContentDefenderAllowsOnlyOneSpecificContentType()

protected function getDefValsForContentDefenderAllowsOnlyOneSpecificContentType(string $cType, int $colPos): ?array
    {
        $allowedCTypes = (array)$this->tcaRegistry->getAllowedCTypesInColumn($cType, $colPos);
        if (count($allowedCTypes) === 1) {
            return ['CType' => $allowedCTypes[0]];
        }
        return null;
    }

The function only returns the CType to the defVal parameters.

Suggested Fix

Comparison with TYPO3 core backend-layout:

mod.web_layout.BackendLayouts {
    Subpage {
        title = Subpage
        config {
            backend_layout {
                colCount = 1
                rowCount = 2
                rows {
                    1 {
                        columns {
                            1 {
                                name = Header
                                colPos = 1
                                allowedContentTypes = header

                            }
                        }
                    }

                    2 {
                        columns {
                            1 {
                                name = Content
                                colPos = 0
                            }
                        }
                    }
                }
            }
        }
    }
}

When adding content to the header column, and in contrast to EXT:containr, the New Content Element Wizard is opened with the one allowed CType

which results in the creation Options being applied:

My suggestion is to remove the function to let TYPO3 handle the defaultValues/ creationOptions. This will have EXT:container use the same behaviour as TYPO3 core (display the New Content Element Wizard) when there is only one allowed content element type in the column.

I will add a PR.