Typed parameter with = null without explicitly marking it as nullable breaks backend

[helmutstrasser]

The method FelixNagel\T3extblog\Controller\AbstractController::xmlResponse() declares a typed parameter with = null without explicitly marking it as nullable, which is deprecated since PHP 8.4. This results in a deprecation warning in the json string of the ajax request in the backend, which breaks it.

Change line 281 from
protected function xmlResponse(string $xml = null): ResponseInterface
to
protected function xmlResponse(?string $xml = null): ResponseInterface
to fix the deprecation warning.

This is already fixed for TYPO3 v14, so this is a backport for v13, which should also work with PHP 8.4

[fnagel]

Thanks for your contribution and I'm very sorry, but I can't accept your PR 🙈

This change is already part of the TYPO3 v13 branch, see 80f9c51
I think the confusion is because of the branch name 9.x (version number in TER) and my old WIP branch ´typo3-13´

Please see the readme which explains which branch is suitable for which TYPO3 version:
https://github.com/fnagel/t3extblog?tab=readme-ov-file#installation

[fnagel]

Any feedback on this issue?

[helmutstrasser]

Ah, sorry Felix, I thought you closed the issue with your last comment.
Ok, so, no problem at all, thank you very much! Then, this issue is solved :)