args: Add passthrough method and tests

Library/Homebrew/cli/args.rb

@@ -21,16 +21,14 @@ module Homebrew
       end
 
       def cli_args
-        return @cli_args unless @cli_args.nil?
+        return @cli_args if @cli_args
 
         @cli_args = []
         processed_options.each do |short, long|
           option = long || short
           switch = "#{option_to_name(option)}?".to_sym
           flag = option_to_name(option).to_sym
-          if @table[switch].instance_of? TrueClass
+          if @table[switch] == true || @table[flag] == true
-            @cli_args << option
-          elsif @table[flag].instance_of? TrueClass
             @cli_args << option
           elsif @table[flag].instance_of? String
             @cli_args << option + "=" + @table[flag]
@@ -48,6 +46,10 @@ module Homebrew
       def flags_only
         @flags_only ||= cli_args.select { |arg| arg.start_with?("--") }
       end
+
+      def passthrough
+        options_only - CLI::Parser.global_options.values.map(&:first).flatten
+      end
     end
   end
 end

Library/Homebrew/cmd/cat.rb

@@ -25,7 +25,6 @@ module Homebrew
     raise "`brew cat` doesn't support multiple arguments" if args.remaining.size > 1
 
     cd HOMEBREW_REPOSITORY
-    cat_args = Homebrew.args.options_only - CLI::Parser.global_options.values.map(&:first).flatten
+    safe_system "cat", formulae.first.path, *Homebrew.args.passthrough
-    safe_system "cat", formulae.first.path, *cat_args
   end
 end

Library/Homebrew/cmd/list.rb

@@ -70,8 +70,7 @@ module Homebrew
         puts Formatter.columns(full_names)
       else
         ENV["CLICOLOR"] = nil
-        ls_args = Homebrew.args.options_only - CLI::Parser.global_options.values.map(&:first).flatten
+        safe_system "ls", *Homebrew.args.passthrough << HOMEBREW_CELLAR
-        safe_system "ls", *ls_args << HOMEBREW_CELLAR
       end
     elsif args.verbose? || !$stdout.tty?
       system_command! "find", args: ARGV.kegs.map(&:to_s) + %w[-not -type d -print], print_stdout: true

Library/Homebrew/test/cli/parser_spec.rb

@@ -230,5 +230,10 @@ describe Homebrew::CLI::Parser do
       parser.parse(["--foo", "--bar=value", "-v", "-s", "a", "b", "cdefg"])
       expect(Homebrew.args.flags_only).to eq %w[--foo --bar=value --verbose]
     end
+
+    it "#passthrough" do
+      parser.parse(["--foo", "--bar=value", "-v", "-s", "a", "b", "cdefg"])
+      expect(Homebrew.args.passthrough).to eq %w[--foo --bar=value -s]
+    end
   end
 end