Regex to *not* match any characters

Question

I know it is quite some weird goal here but for a quick and dirty fix for one of our system we do need to not filter any input and let the corruption go into the system.

Answer 1

Another very well supported and fast pattern that would fail to match anything that is guaranteed to be constant time:

$unmatchable pattern $anything goes here etc.

$ of course indicates the end-of-line. No characters could possibly go after $ so no further state transitions could possibly be made. The additional advantage are that your pattern is intuitive, self-descriptive and readable as well!