That’s quite a drastic change because this means that it won’t be possible to share the same rate limiter across routes, whereas, before this PR, it was already possible to get per route rate limiters with a custom KeyResolver (which is what we actually did).

@DidierLoiseau I think you were operating a bit unintentionally where this fixed a real bug. I'm curious if the new bucket4j implementation might work in your case. I've also opened #3694

This is a breaking change.
I just upgraded to version 4.2 and found that all my limits, shared by dozens of routes, no longer work.
For me it was a feature not a bug. I could choose to add the route_id by creating my KeyResolver and now I can no longer do that.

With a KeyResolver like this I could get the same result that is now imposed:

Mono.fromSupplier( () -> {
                    final Route route = exchange.getAttribute(GATEWAY_ROUTE_ATTR);
                    return route.getId() + "." + "...my_key...";
 });

The only option I think at this point is to duplicate the RedisRateLimiter code and fix it: I don't think I can extend RedisRateLimiter because unfortunately getKeys is a static method and I can`t override it.

I hope this modification can be overhauled.