improve ruby syntax check and fix fail_on_warnings usage

Author: mschuchard

CHANGELOG.md

@@ -1,9 +1,11 @@
 ### 2.4.0 (Next)
+- Minimum Ruby version increased to 3.0.
 - Fix `rubocop-performance` inclusion warning.
 - Improve recognition of Ruby support files during filesystem parsing.
 - Fix `file` task for no settings override usage.
-- Minimum Ruby version increased to 3.0.
 - Add `rubocop-rspec` plugin to Ruby checks.
+- Fix `--fail-on-warnings` functionality.
+- Improve safety of Ruby syntax checks.
 
 ### 2.3.1
 - No input target paths now defaults to current working directory instead of error.

lib/puppet-check/ruby_parser.rb

@@ -17,8 +17,7 @@ def self.ruby(files, style, rc_args)
 
     files.each do |file|
       # check ruby syntax
-      # prevents ruby code from actually executing the input ruby file
-      catch(:good) { instance_eval("BEGIN {throw :good}; #{File.read(file)} # BEGIN {throw :good}; ruby_file_content", file) }
+      RubyVM::InstructionSequence.compile_file(file)
     rescue ScriptError, StandardError => err
       PuppetCheck.files[:errors][file] = err.to_s.gsub("#{file}:", '').split("\n")
     else

lib/puppet_check.rb

@@ -33,7 +33,7 @@ def run(settings = {}, paths = [])
     OutputResults.run(parsed_files.clone, settings[:output_format])
 
     # progress to regression checks if no errors in file checks
-    if parsed_files[:errors].empty? && (!settings[:fail_on_warning] || parsed_files[:warnings].empty?)
+    if parsed_files[:errors].empty? && (!settings[:fail_on_warnings] || parsed_files[:warnings].empty?)
       begin
         require_relative 'puppet-check/regression_check'