From 3aa7ebc7db8cd833dadae1235750a72bb2a04ba9 Mon Sep 17 00:00:00 2001
From: Kyrylo Silin <silin@kyrylo.org>
Date: Fri, 26 Oct 2018 04:33:36 +0800
Subject: [PATCH] repl: fix broken input while using rb-readline

Fixes #1823 (Broken upstream when rb-readline is enabled)
---
 lib/pry/repl.rb | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/pry/repl.rb b/lib/pry/repl.rb
index f3a7b7fa..afc7864d 100644
--- a/lib/pry/repl.rb
+++ b/lib/pry/repl.rb
@@ -241,7 +241,11 @@ class Pry
     #   indicators in 99% of cases.
     def calculate_overhang(current_prompt, original_val, indented_val)
       overhang = original_val.length - indented_val.length
-      if readline_available? && Readline.vi_editing_mode?
+      if readline_available? &&
+         # rb-readline doesn't support this method:
+         # https://github.com/ConnorAtherton/rb-readline/issues/152
+         Readline.respond_to?(:vi_editing_mode?) &&
+         Readline.vi_editing_mode?
         overhang += current_prompt.length - indented_val.length
       end
       [0, overhang].max