convenient_service.gemspec in convenient_service-0.16.0 vs convenient_service.gemspec in convenient_service-0.17.0

@@ -70,14 +70,19 @@
   # - https://github.com/deivid-rodriguez/byebug/issues/179#issuecomment-152727003
   #
   spec.add_development_dependency "byebug", "~> 10.0" unless ConvenientService::Support::Ruby.jruby?
 
   ##
+  # Used for parsing Markdown in YARD docs.
+  # - https://github.com/gjtorikian/commonmarker
+  #
   # NOTE: `commonmarker` has C extensions, that is why it is NOT supported in JRuby.
   # - https://github.com/gjtorikian/commonmarker/tree/main/ext/commonmarker
   #
-  spec.add_development_dependency "commonmarker" unless ConvenientService::Support::Ruby.jruby?
+  # TODO: `commonmarker` v1 does NOT work with `yard-junk`.
+  #
+  spec.add_development_dependency "commonmarker", "~> 0.23.10" unless ConvenientService::Support::Ruby.jruby?
 
   ##
   # Used for debugging CRuby code.
   # Has almost the same public API as `byebug`, but supports frame filtering.
   # Check `break` if you need to debug JRuby.
@@ -120,12 +125,17 @@
   # - https://github.com/mbj/mutant
   # - https://github.com/mbj/mutant/blob/main/docs/nomenclature.md
   # - https://github.com/mbj/mutant/blob/main/docs/mutant-rspec.md
   # - https://github.com/mbj/mutant/blob/main/docs/incremental.md
   #
-  spec.add_development_dependency "mutant", "~> 0.11.21"
-  spec.add_development_dependency "mutant-rspec", "~> 0.11.21"
+  # NOTE: How to get a licence key?
+  # - https://github.com/mbj/mutant/issues/1396
+  #
+  if ::ENV["CONVENIENT_SERVICE_MUTANT_LICENCE_KEY"]
+    spec.add_development_dependency "mutant", "~> 0.11.21"
+    spec.add_development_dependency "mutant-rspec", "~> 0.11.21"
+  end
 
   ##
   # Used for coloring logs.
   # - https://github.com/janlelis/paint
   #
@@ -188,12 +198,21 @@
   #
   spec.add_development_dependency "stackprof", "~> 0.2.25" unless ConvenientService::Support::Ruby.jruby?
 
   spec.add_development_dependency "webrick"
 
-  spec.add_development_dependency "yard", "~> 0.9.28"
+  ##
+  # Used for generation of API docs for Ruby code.
+  # - https://github.com/lsegal/yard
+  # - https://yardoc.org
+  #
+  spec.add_development_dependency "yard", "~> 0.9.34"
 
-  spec.add_development_dependency "yard-junk"
+  ##
+  # Used for linting YARD docs.
+  # - https://github.com/zverok/yard-junk
+  #
+  spec.add_development_dependency "yard-junk", "~> 0.0.9"
 
   ##
   # The following gems are Convenient Service alternatives.
   # Used for performance comparisons.
   # See `benchmark/empty_service`.