hm well, the request context cannot only be updated for the master request because the matching process of course needs the current request info. but for generating urls it's actually quite useless to do that inside subrequests based on the subrequest info. this is not only relevant for relative paths, but also when examining whether the host or scheme changed for absolute paths.

what this means is that matching/generating would need different request contexts:
matching urls process -> needs current request info
generating urls process -> should only be based on the master request info