TYPO3 Core

Confirmation and analysis/background¶

I could confirm the issue. The `PageContentErrorHandler`
makes only sub-requests to the same instance, which has
been introduced with #94402 and #98396. External URL's,
which are valid target to be set with the link handling
in the backend, this could never work and retrieve the
external error page content.

The linktype of the resolved url params can be used to
distinguish which type or error page link it is, and use
either the sub-request or external request based on the
link type.

Note: External requests may still hit the same instance,
and could lead to resolving loops if the resource is not
available as external request. This must be guarded
and detected.

Additional notes / remarks¶

https://zazu.berlin/404.html/

is a invalid url and hits a real server error page
with an 404 status code. The correct URL would be

https://zazu.berlin/404.html

without the ending slash. Assumed, the TYPO3 Core
PageContentErrorHandler would execute a real request
the contend could be retrieved correctly.

A external url returning 404 should and must be
considered as "not available/found" and thus fallback
to a generic "not resolved" response.

Patch set 2 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947

Patch set 3 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947

Patch set 4 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947

Patch set 5 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947

Patch set 6 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83947

Patch set 1 for branch 12.4 of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/83978