[ruby/irb] Fix step command (https://github.com/ruby/irb/pull/477)

The current `next` pre-command workaround on IRB source stepping
moves the location by 1 extra line. A better way is to make `debug`
skip IRB frames completely, which is what this commit does.

It also fixes the step command's test. The `|` in regexp was not escaped
so it was always incorrectly matched.

2 files changed, 10 insertions, 2 deletions

diff --git a/lib/irb/cmd/debug.rb b/lib/irb/cmd/debug.rb
index 76f17e3c2f..e6e812e075 100644
--- a/lib/irb/cmd/debug.rb
+++ b/lib/irb/cmd/debug.rb
@@ -55,6 +55,13 @@ module IRB
         end
       end
 
+      module SkipPathHelperForIRB
+        def skip_internal_path?(path)
+          # The latter can be removed once https://github.com/ruby/debug/issues/866 is resolved
+          super || path.match?(IRB_DIR) || path.match?('<internal:prelude>')
+        end
+      end
+
       def setup_debugger
         unless defined?(DEBUGGER__::SESSION)
           begin
@@ -75,6 +82,8 @@ module IRB
             end
             frames
           end
+
+          DEBUGGER__::ThreadClient.prepend(SkipPathHelperForIRB)
         end
 
         true
diff --git a/lib/irb/cmd/step.rb b/lib/irb/cmd/step.rb
index d3d0f16291..2bc74a9d79 100644
--- a/lib/irb/cmd/step.rb
+++ b/lib/irb/cmd/step.rb
@@ -8,8 +8,7 @@ module IRB
   module ExtendCommand
     class Step < DebugCommand
       def execute(*args)
-        # Run `next` first to move out of binding.irb
-        super(pre_cmds: "next", do_cmds: ["step", *args].join(" "))
+        super(do_cmds: ["step", *args].join(" "))
       end
     end
   end