[ruby/irb] Add debug command (https://github.com/ruby/irb/pull/446)

https://github.com/ruby/irb/commit/30faa13fa3

1 files changed, 33 insertions, 0 deletions

diff --git a/lib/irb/cmd/debug.rb b/lib/irb/cmd/debug.rb
new file mode 100644
index 0000000000..8aab40cf84
--- /dev/null
+++ b/lib/irb/cmd/debug.rb
@@ -0,0 +1,33 @@
+require_relative "nop"
+
+module IRB
+  # :stopdoc:
+
+  module ExtendCommand
+    class Debug < Nop
+      def execute(*args)
+        require "debug/session"
+        DEBUGGER__.start(nonstop: true)
+        DEBUGGER__.singleton_class.send(:alias_method, :original_capture_frames, :capture_frames)
+
+        def DEBUGGER__.capture_frames(skip_path_prefix)
+          frames = original_capture_frames(skip_path_prefix)
+          frames.reject! do |frame|
+            frame.realpath&.start_with?(::IRB::Irb::DIR_NAME) || frame.path.match?(/internal:prelude/)
+          end
+          frames
+        end
+
+        file, lineno = IRB::Irb.instance_method(:debug_break).source_location
+        DEBUGGER__::SESSION.add_line_breakpoint(file, lineno + 1, oneshot: true, hook_call: false)
+        # exit current Irb#run call
+        throw :IRB_EXIT
+      rescue LoadError => e
+        puts <<~MSG
+          You need to install the debug gem before using this command.
+          If you use `bundle exec`, please add `gem "debug"` into your Gemfile.
+        MSG
+      end
+    end
+  end
+end