Fix #205: Handle optparse errors gracefully

lib/colorls/flags.rb

@@ -113,6 +113,15 @@ def add_general_options(options)
       options.on('--hyperlink') { @opts[:hyperlink] = true }
     end
 
+    def add_help_option(opts)
+      opts.separator ''
+      opts.on_tail('-h', '--help', 'prints this help') do
+        puts @parser
+        show_examples
+        exit
+      end
+    end
+
     def show_examples
       puts <<EXAMPLES.gsub(/^  /, '')
 
@@ -146,13 +155,8 @@ def parse_options
         add_common_options(opts)
         add_sort_options(opts)
         add_general_options(opts)
+        add_help_option(opts)
 
-        opts.separator ''
-        opts.on_tail('-h', '--help', 'prints this help') do
-          puts @parser
-          show_examples
-          exit
-        end
         opts.on_tail('--version', 'show version') do
           puts ColorLS::VERSION
           exit
@@ -162,6 +166,9 @@ def parse_options
       @parser.parse!(@args)
 
       set_color_opts
+    rescue OptionParser::ParseError => e
+      warn "colorls: #{e}\nSee 'colorls --help'."
+      exit 2
     end
 
     def set_color_opts

spec/color_ls/flags_spec.rb

@@ -167,4 +167,16 @@ def capture_stdout
 
     it { is_expected.to match(/yaml_sort_checker.rb/) }
   end
+
+  context 'when passing invalid flags' do
+    let(:args) { ['--snafu'] }
+
+    it 'should issue a warning, hint about `--help` and exit' do
+      allow(::Kernel).to receive(:warn) do |message|
+        expect(message).to match "--snafu"
+      end
+
+      expect { subject }.to raise_error(SystemExit).and output(/--help/).to_stderr
+    end
+  end
 end