SYSTEM-MUTABLE-P take a real *SYSTEM* as argument, instead of having an odd API where only a system-NAME is acceptable.
note:
CL-USER> (asdf:coerce-name (asdf:find-system :hu.dwim.def)) "hu.dwim.def"
I think having a confusing name that we deprecate is better than taking the good name, and implementing something bad on it. This way we can think about a better API and put the better API on the better name.
i thought (and stated previously, with a doubt) that RIS is something new, but now that i double checked i realized it's already there since 2014 aug, exported:
https://github.com/fare/asdf/commit/1b38225b8cc5749fafac9f300ac469fd92beba86
it's a lost case then, it's already published, so there's no way other than the deprecation way. in that case it's not an urgent issue, just put it on the TODO.
sorry for the noise!