[ruby/reline] Editing to initial content is not just cursor moving

https://github.com/ruby/reline/commit/0a4f175b0a

lib/reline/line_editor.rb

@@ -933,6 +933,7 @@ class Reline::LineEditor
       finish
       return
     end
+    old_line = @line.dup
     @first_char = false
     completion_occurs = false
     if @config.editing_mode_is?(:emacs, :vi_insert) and key.char == "\C-i".ord
@@ -964,7 +965,7 @@ class Reline::LineEditor
     if not Reline::IOGate.in_pasting? and @just_cursor_moving.nil?
       if @previous_line_index and @buffer_of_lines[@previous_line_index] == @line
         @just_cursor_moving = true
-      elsif @previous_line_index.nil? and @buffer_of_lines[@line_index] == @line
+      elsif @previous_line_index.nil? and @buffer_of_lines[@line_index] == @line and old_line == @line
         @just_cursor_moving = true
       else
         @just_cursor_moving = false

test/reline/yamatanooroti/test_rendering.rb

@@ -441,6 +441,17 @@ begin
       EOC
     end
 
+    def test_backspace_until_returns_to_initial
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl}, startup_message: 'Multiline REPL.')
+      write("ABC")
+      write("\C-h\C-h\C-h")
+      close
+      assert_screen(<<~EOC)
+        Multiline REPL.
+        prompt>
+      EOC
+    end
+
     private def write_inputrc(content)
       File.open(@inputrc_file, 'w') do |f|
         f.write content