TYPO3 Core

My conclusion would be: Any plugin that needs a redirect, should be marked as not cachable.

If there is a valid case for giving cached plugins the possiblity to perform a permanent redirect,
then this redirect should be stored in the cache and be handled right after the cache is retrieved.

A usecase, which contradicts this change request.

Consider a cachable show action for a seminar date. This view can be fully cached, it mostly never changes.
In case the seminar date has to be cancelled, the state of the seminar date is changed and the respective cache entry is flushed.
The show action then issues a redirect to an overview page, in case the page for this seminar date is still accessed by someone.
The redirect is so to say permanent, but since the core does not store the HTTP headers with the cache content, this redirect response must not be cached.

Patch set 2 for branch master of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/60518

Thanks for the use case. There would have been multiple ways to achieve desired behavior without introducing such core change, which seems pretty intrusive to me.

1. Using HttpUtility::redirect (or throw new DirectResponseException in 9.5 and higher)
2. Disabling the page cache using TSFE->set_no_cache (which is done e.g. in News extension)
3. Throw a 404 and handle the 404 accordingly in a custom 404 handler
4. Convert the plugin to USER_INT before issuing the redirect

I added the last to Extbase redierctToUri as I don't see a use case for issuing a redirect and at the same time have the same plugin action cached (which only works currently at cost of always rendering the complete page, writing and then again removing the page cache)

Patch set 1 for branch 9.5 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/60684