Suppress crashing when auto_indent_proc returns broken indent info

Co-authored-by: Juanito Fatas <me@juanitofatas.com>

Author: aycabta

bin/multiline_repl

@@ -22,6 +22,9 @@ opt.on('--dynamic-prompt') {
     }
   }
 }
+opt.on('--auto-indent') {
+  AutoIndent.new
+}
 opt.parse!(ARGV)
 
 begin

bin/termination_checker.rb

@@ -16,3 +16,15 @@ def terminated?(code)
     end
   end
 end
+
+class AutoIndent < RubyLex
+  def initialize
+    set_input(self)
+    context = Struct.new(:auto_indent_mode).new(true)
+    set_auto_indent(context)
+  end
+
+  def auto_indent(&block)
+    Reline.auto_indent_proc = block
+  end
+end

lib/reline/line_editor.rb

@@ -1131,6 +1131,7 @@ def call_completion_proc
       new_lines = whole_lines
     end
     new_indent = @auto_indent_proc.(new_lines, @line_index, @byte_pointer, @check_new_auto_indent)
+    new_indent = @cursor_max if new_indent&.> @cursor_max
     if new_indent&.>= 0
       md = new_lines[@line_index].match(/\A */)
       prev_indent = md[0].count(' ')

test/reline/yamatanooroti/test_rendering.rb

@@ -637,6 +637,20 @@ def test_update_cursor_correctly_when_just_cursor_moving
       EOC
     end
 
+    def test_suppress_auto_indent_just_after_pasted
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/bin/multiline_repl --auto-indent}, startup_message: 'Multiline REPL.')
+      write("def hoge\n  [[\n      3]]\ned")
+      write("\C-bn")
+      close
+      assert_screen(<<~EOC)
+        Multiline REPL.
+        prompt> def hoge
+        prompt>   [[
+        prompt>       3]]
+        prompt> end
+      EOC
+    end
+
     private def write_inputrc(content)
       File.open(@inputrc_file, 'w') do |f|
         f.write content