TYPO3 Core

No, this is a different problem. Its not about suppressing errors from wrong preg-expressions.

It is about the match zero value from the preg_match-function, which always contains the question mark if the redirect has the "Respect GET Parameters"-flag set. If the target url does not contain a $0-placeholder, the redirectService should not write the "Unsafe captching group regex..."-warning in the log file.

Actually the other patch would suppress all preg_match errors, not only from "wrong" ones.
But thank you for the reply, will try to reproduce and analyze

@Mordamir Can you provide some example ?

The used regexp string and the url/request matching that request but triggering the error ? (one or two examples) ?

As Source Path

#^/partner\?tx_extension_clients.+client(?:%5D|\])=([A-Z0-9]+)#

/partner/$1