Merge pull request #4613 from tnir/4612-beter-gem-help-build

Fix `gem help build` output format

(cherry picked from commit 608c4e4)

Author: simi

lib/rubygems/command.rb

@@ -355,6 +355,8 @@ def when_invoked(&block)
   def add_option(*opts, &handler) # :yields: value, options
     group_name = Symbol === opts.first ? opts.shift : :options
 
+    raise "Do not pass an empty string in opts" if opts.include?("")
+
     @option_groups[group_name] << [opts, handler]
   end
 

lib/rubygems/commands/build_command.rb

@@ -23,7 +23,7 @@ def initialize
       options[:output] = value
     end
 
-    add_option '-C PATH', '', 'Run as if gem build was started in <PATH> instead of the current working directory.' do |value, options|
+    add_option '-C PATH', 'Run as if gem build was started in <PATH> instead of the current working directory.' do |value, options|
       options[:build_path] = value
     end
   end

test/rubygems/test_gem_command.rb

@@ -189,6 +189,18 @@ def test_invoke_with_options
     assert_match %r{Usage: gem doit}, @ui.output
   end
 
+  def test_add_option
+    assert_nothing_raised RuntimeError do
+      @cmd.add_option('--force', 'skip validation of the spec') {|v,o| }
+    end
+  end
+
+  def test_add_option_with_empty
+    assert_raise RuntimeError, "Do not pass an empty string in opts" do
+      @cmd.add_option('', 'skip validation of the spec') {|v,o| }
+    end
+  end
+
   def test_option_recognition
     @cmd.add_option('-h', '--help [COMMAND]', 'Get help on COMMAND') do |value, options|
       options[:help] = true

test/rubygems/test_gem_commands_help_command.rb

@@ -35,6 +35,13 @@ def test_gem_help_platforms
     end
   end
 
+  def test_gem_help_build
+    util_gem 'build' do |out, err|
+      assert_match(/-C PATH *Run as if gem build was started in <PATH>/, out)
+      assert_equal '', err
+    end
+  end
+
   def test_gem_help_commands
     mgr = Gem::CommandManager.new