[ruby/irb] Print deprecation warning for `help` commandHEADmaster

(https://github.com/ruby/irb/pull/567)

* Give show_doc its own command class

* Print deprecation warning for `help` command

1 files changed, 12 insertions, 44 deletions

diff --git a/lib/irb/cmd/help.rb b/lib/irb/cmd/help.rb
index 539d20a119..64b885c383 100644
--- a/lib/irb/cmd/help.rb
+++ b/lib/irb/cmd/help.rb
@@ -1,55 +1,23 @@
-# frozen_string_literal: false
-#
-#   help.rb - helper using ri
-#
+# frozen_string_literal: true
 
-require_relative "nop"
+require_relative "show_doc"
 
 module IRB
-  # :stopdoc:
-
   module ExtendCommand
-    class Help < Nop
-      class << self
-        def transform_args(args)
-          # Return a string literal as is for backward compatibility
-          if args.empty? || string_literal?(args)
-            args
-          else # Otherwise, consider the input as a String for convenience
-            args.strip.dump
-          end
-        end
-      end
-
+    class Help < ShowDoc
       category "Context"
-      description "Enter the mode to look up RI documents."
-
-      def execute(*names)
-        require 'rdoc/ri/driver'
-
-        unless self.class.const_defined?(:Ri)
-          opts = RDoc::RI::Driver.process_args([])
-          self.class.const_set(:Ri, RDoc::RI::Driver.new(opts))
-        end
+      description "[DEPRECATED] Enter the mode to look up RI documents."
 
-        if names.empty?
-          Ri.interactive
-        else
-          names.each do |name|
-            begin
-              Ri.display_name(name.to_s)
-            rescue RDoc::RI::Error
-              puts $!.message
-            end
-          end
-        end
+      DEPRECATION_MESSAGE = <<~MSG
+        [Deprecation] The `help` command will be repurposed to display command help in the future.
+        For RI document lookup, please use the `show_doc` command instead.
+        For command help, please use `show_cmds` for now.
+      MSG
 
-        nil
-      rescue LoadError, SystemExit
-        warn "Can't display document because `rdoc` is not installed."
+      def execute(*names)
+        warn DEPRECATION_MESSAGE
+        super
       end
     end
   end
-
-  # :startdoc:
 end