Merge pull request #12866 from nathan7/rubygem-drvname-fix

buildRubyGem: ensure gem versions don't get misparsed

pkgs/development/interpreters/ruby/build-ruby-gem/default.nix

···
 , platform ? "ruby"
 , ruby ? defs.ruby
 , stdenv ? ruby.stdenv
-, namePrefix ? "${ruby.name}" + "-"
+, namePrefix ? (let
+    rubyName = builtins.parseDrvName ruby.name;
+  in "${rubyName.name}${rubyName.version}-")
 , buildInputs ? []
 , doCheck ? false
 , meta ? {}
···
     ++ lib.optional stdenv.isDarwin darwin.libobjc
     ++ buildInputs;
 
-  name = attrs.name or (namePrefix + gemName);
+  name = attrs.name or "${namePrefix}${gemName}-${version}";
 
   inherit src;