help_spec: fix and generate help text in help.rb

Library/Homebrew/cli_parser.rb

@@ -35,11 +35,8 @@ module Homebrew
 
       def post_initialize
         @parser.on_tail("-h", "--help", "Show this message") do
-          puts @parser.to_s.sub(/^/, "#{Tty.bold}Usage: brew#{Tty.reset} ")
+          puts generate_help_text
-                      .gsub(/`(.*?)`/, "#{Tty.bold}\\1#{Tty.reset}")
+          exit 0
-                      .gsub(%r{<([^\s]+?://[^\s]+?)>}) { |url| Formatter.url(url) }
-                      .gsub(/<(.*?)>/, "#{Tty.underline}\\1#{Tty.reset}")
-          exit
         end
       end
 
@@ -128,6 +125,13 @@ module Homebrew
         Homebrew::CLI::Parser.global_options.key?(name.to_sym)
       end
 
+      def generate_help_text
+        @parser.to_s.sub(/^/, "#{Tty.bold}Usage: brew#{Tty.reset} ")
+               .gsub(/`(.*?)`/, "#{Tty.bold}\\1#{Tty.reset}")
+               .gsub(%r{<([^\s]+?://[^\s]+?)>}) { |url| Formatter.url(url) }
+               .gsub(/<(.*?)>/, "#{Tty.underline}\\1#{Tty.reset}")
+      end
+
       private
 
       def enable_switch(*names)

Library/Homebrew/help.rb

@@ -38,14 +38,6 @@ module Homebrew
     module_function
 
     def help(cmd = nil, flags = {})
-      # Let OptionParser generate help text for commands which have a parser defined
-      begin
-        Homebrew.send("#{cmd.tr("-", "_")}_args".to_sym)
-        return
-      rescue NoMethodError
-        nil
-      end
-
       # Resolve command aliases and find file containing the implementation.
       if cmd
         cmd = HOMEBREW_INTERNAL_COMMAND_ALIASES.fetch(cmd, cmd)
@@ -83,6 +75,14 @@ module Homebrew
     end
 
     def command_help(path)
+      # Let OptionParser generate help text for commands which have a parser defined
+      begin
+        cmd = path.basename(path.extname)
+        return Homebrew.send("#{cmd.to_s.tr("-", "_")}_args".to_sym).generate_help_text
+      rescue NoMethodError
+        nil
+      end
+
       help_lines = command_help_lines(path)
       if help_lines.empty?
         opoo "No help text in: #{path}" if ARGV.homebrew_developer?

Library/Homebrew/test/cmd/help_spec.rb

@@ -26,7 +26,7 @@ describe "brew", :integration_test do
 
     it "prints help for a documented Ruby developer command" do
       expect { brew "help", "update-test" }
-        .to output(/^brew update-test/).to_stdout
+        .to output(/^Usage: brew update-test/).to_stdout
         .and be_a_success
     end