The trigger here looks to be a patch[1] in rubygems. I've tried rebuilding rake-compiler without that patch and the failing test seems to pass again.
It looks like folks have noticed this in jekyll[2] and it also seems there's already a Debian bug filed against rubygems for this issue[3] but for a different kind of breakage. I'm not sure whether dropping the patch in rubygems or modifying rake-compiler to work with the Debian patch makes more sense, but clearly something needs to happen to harmonize these two packages. 1: https://salsa.debian.org/ruby-team/rubygems/-/blob/master/debian/patches/0002-Gem-Platform-emulate-3.3.15-behavior-on-Ruby-3.1.patch?ref_type=heads 2: https://github.com/jekyll/jekyll/issues/9478 3: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1069089 -- Mike Gerow [email protected]

