Only warn if locale settings are broken

Keep running if calling `setlocale` fails, because of invalid locale settings.

Fixes #335.

lib/colorls/flags.rb

@@ -37,8 +37,7 @@ def initialize(*args)
     end
 
     def process
-      # initialize locale from environment
-      CLocale.setlocale(CLocale::LC_COLLATE, '')
+      init_locale
 
       @args = [Dir.pwd] if @args.empty?
       @args.sort!.each_with_index do |path, i|
@@ -69,6 +68,13 @@ def options
 
     private
 
+    def init_locale
+      # initialize locale from environment
+      CLocale.setlocale(CLocale::LC_COLLATE, '')
+    rescue RuntimeError => e
+      warn "WARN: #{e}, check your locale settings"
+    end
+
     def add_sort_options(options)
       options.separator ''
       options.separator 'sorting options:'

spec/color_ls/flags_spec.rb

@@ -290,4 +290,14 @@
       expect { subject }.to raise_error('colorls exited with 2').and output(/--help/).to_stderr
     end
   end
+
+  context 'for invalid locale' do
+    let(:args) { [FIXTURES] }
+
+    it 'should warn but not raise an error' do
+      allow(CLocale).to receive(:setlocale).with(CLocale::LC_COLLATE, '').and_raise(RuntimeError.new("setlocale error"))
+
+      expect { subject }.to output(/setlocale error/).to_stderr.and output.to_stdout
+    end
+  end
 end