refactor: use $LOADED_FEATURES built-in instead of $"

[pvdb]

tl;dr - replace$" with the equivalent - but much more descriptive - $LOADED_FEATURES Ruby built-in ... and work around an apparent parsing bug in "universal" ctags while we're at it (see details below)

Thanks @hsbt 🙏

---

I noticed that quite a few methods defined in lib/rake/application.rb were missing from a tags file generated by the latest version of "universal" ctags.

On closer examination, it turns out that all methods defined after the rake_require method (defined here in the Ruby source file) don't get indexed by ctags:

    def rake_require(file_name, paths=$LOAD_PATH, loaded=$") # :nodoc:
      ...
    end

After some experimentation - and most likely due to a parsing bug in ctags - it turns out that Ruby's $" built-in is hmmm "confusing" ctags and causing it to generate a partial list of tags; using $LOADED_FEATURES instead of $" fixes the issue:

    def rake_require(file_name, paths=$LOAD_PATH, loaded=$LOADED_FEATURES) # :nodoc:
      ...
    end

$LOADED_FEATURES used to be an alias for $" defined in English.rb, but in ruby 1.9.3 (ruby/ruby@6dcbfbc) it was removed as an alias and was implemented as a "proper" built-in, so no additional require is needed for this change (especially considering rake has been targeting ruby v2.3 and above).

And if nothing else - even putting the tags issue aside - this change makes the code more readable and self-explanatory IMO.

Finally, by diffing the output of running:

ctags -f - --sort=no lib/rake/application.rb

... on the master branch as well as this PR's branch, it's easy to see that using $LOADED_FEATURES indeed results in all Ruby methods getting indexed, even the ones coming after the"problematic" rake_require method:

$ git rev-diff master loaded_features_builtin ctags -f - --sort=no lib/rake/application.rb
--- git checkout master && { ctags -f - --sort=no lib/rake/application.rb ; } ;
+++ git checkout loaded_features_builtin && { ctags -f - --sort=no lib/rake/application.rb ; } ;
@@ -51,4 +51,17 @@
 select_tasks_to_show        lib/rake/application.rb  /^    def select_tasks_to_show(options, show_tasks, value) # :nodoc:$/;"                    f  class:Rake.Application
 select_trace_output         lib/rake/application.rb  /^    def select_trace_output(options, trace_option, value) # :nodoc:$/;"                   f  class:Rake.Application
 handle_options              lib/rake/application.rb  /^    def handle_options(argv) # :nodoc:$/;"                                                f  class:Rake.Application
-rake_require                lib/rake/application.rb  /^    def rake_require(file_name, paths=$LOAD_PATH, loaded=$") # :nodoc:$/;"                f  class:Rake.Application
+rake_require                lib/rake/application.rb  /^    def rake_require(file_name, paths=$LOAD_PATH, loaded=$LOADED_FEATURES) # :nodoc:$/;"  f  class:Rake.Application
+find_rakefile_location      lib/rake/application.rb  /^    def find_rakefile_location # :nodoc:$/;"                                              f  class:Rake.Application
+print_rakefile_directory    lib/rake/application.rb  /^    def print_rakefile_directory(location) # :nodoc:$/;"                                  f  class:Rake.Application
+raw_load_rakefile           lib/rake/application.rb  /^    def raw_load_rakefile # :nodoc:$/;"                                                   f  class:Rake.Application
+glob                        lib/rake/application.rb  /^    def glob(path, &block) # :nodoc:$/;"                                                  f  class:Rake.Application
+system_dir                  lib/rake/application.rb  /^    def system_dir # :nodoc:$/;"                                                          f  class:Rake.Application
+standard_system_dir         lib/rake/application.rb  /^      def standard_system_dir #:nodoc:$/;"                                                S  class:Rake.Application
+standard_system_dir         lib/rake/application.rb  /^      def standard_system_dir #:nodoc:$/;"                                                S  class:Rake.Application
+collect_command_line_tasks  lib/rake/application.rb  /^    def collect_command_line_tasks(args) # :nodoc:$/;"                                    f  class:Rake.Application
+default_task_name           lib/rake/application.rb  /^    def default_task_name # :nodoc:$/;"                                                   f  class:Rake.Application
+add_import                  lib/rake/application.rb  /^    def add_import(fn) # :nodoc:$/;"                                                      f  class:Rake.Application
+load_imports                lib/rake/application.rb  /^    def load_imports # :nodoc:$/;"                                                        f  class:Rake.Application
+rakefile_location           lib/rake/application.rb  /^    def rakefile_location(backtrace=caller) # :nodoc:$/;"                                 f  class:Rake.Application
+set_default_options         lib/rake/application.rb  /^    def set_default_options # :nodoc:$/;"                                                 f  class:Rake.Application
$ _

[hsbt]

Maked sense. Thanks 👍