From a510175e8f95f4d8f7bc56c184996526b530bf94 Mon Sep 17 00:00:00 2001
From: Kenichi Kamiya <kachick1@gmail.com>
Date: Sat, 4 May 2024 07:08:44 +0900
Subject: [PATCH] [ruby/irb] Avoid raising errors while running help for custom
 commands (https://github.com/ruby/irb/pull/944)

* Avoid raising errors while running help for custom commands

Raising an error from the help command is not a pleasure for the
end user, even if the command does not define any attributes

* Update test/irb/command/test_custom_command.rb

---------

https://github.com/ruby/irb/commit/c8bba9f8dc

Co-authored-by: Stan Lo <stan001212@gmail.com>
---
 lib/irb/command/help.rb                 |  2 +-
 test/irb/command/test_custom_command.rb | 26 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/lib/irb/command/help.rb b/lib/irb/command/help.rb
index 1ed7a7707c..995b81bf11 100644
--- a/lib/irb/command/help.rb
+++ b/lib/irb/command/help.rb
@@ -12,7 +12,7 @@ module IRB
             help_message
           else
             if command_class = Command.load_command(command_name)
-              command_class.help_message || command_class.description
+              command_class.help_message || command_class.description || ""
             else
               "Can't find command `#{command_name}`. Please check the command name and try again.\n\n"
             end
diff --git a/test/irb/command/test_custom_command.rb b/test/irb/command/test_custom_command.rb
index 16800db2c8..eac0bd3495 100644
--- a/test/irb/command/test_custom_command.rb
+++ b/test/irb/command/test_custom_command.rb
@@ -123,5 +123,31 @@ module TestIRB
       assert_include(output, "2 FooBar executed")
       assert_include(output, "foobar_description")
     end
+
+    def test_no_meta_command_also_works
+      write_ruby <<~RUBY
+        require "irb/command"
+
+        class NoMetaCommand < IRB::Command::Base
+          def execute(*)
+            puts "This command does not override meta attributes"
+            nil
+          end
+        end
+
+        IRB::Command.register(:no_meta, NoMetaCommand)
+
+        binding.irb
+      RUBY
+
+      output = run_ruby_file do
+        type "no_meta\n"
+        type "help no_meta\n"
+        type "exit"
+      end
+
+      assert_include(output, "This command does not override meta attributes")
+      assert_not_include(output, "Maybe IRB bug")
+    end
   end
 end