[ruby/reline] Implement the undo command

(https://github.com/ruby/reline/pull/701)

* Refactor send

* Implement the undo command

* Fix @past_lines initialization

* Improve assertion

* Hide to save buffer in insert_pasted_text

* Replace @using_delete_command with @undoing

* Refactor `@past_lines`

https://github.com/ruby/reline/commit/4ab72f9cbd

2 files changed, 81 insertions, 0 deletions

diff --git a/test/reline/test_key_actor_emacs.rb b/test/reline/test_key_actor_emacs.rb
index 409a7334cb..013ca2f7b3 100644
--- a/test/reline/test_key_actor_emacs.rb
+++ b/test/reline/test_key_actor_emacs.rb
@@ -1437,4 +1437,72 @@ class Reline::KeyActor::Emacs::Test < Reline::TestCase
     @line_editor.__send__(:vi_editing_mode, nil)
     assert(@config.editing_mode_is?(:vi_insert))
   end
+
+  def test_undo
+    input_keys("\C-_", false)
+    assert_line_around_cursor('', '')
+    input_keys("aあb\C-h\C-h\C-h", false)
+    assert_line_around_cursor('', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('a', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('aあ', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('aあb', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('aあ', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('a', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('', '')
+  end
+
+  def test_undo_with_cursor_position
+    input_keys("abc\C-b\C-h", false)
+    assert_line_around_cursor('a', 'c')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('ab', 'c')
+    input_keys("あいう\C-b\C-h", false)
+    assert_line_around_cursor('abあ', 'うc')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('abあい', 'うc')
+  end
+
+  def test_undo_with_multiline
+    @line_editor.multiline_on
+    @line_editor.confirm_multiline_termination_proc = proc {}
+    input_keys("1\n2\n3", false)
+    assert_whole_lines(["1", "2", "3"])
+    assert_line_index(2)
+    assert_line_around_cursor('3', '')
+    input_keys("\C-p\C-h\C-h", false)
+    assert_whole_lines(["1", "3"])
+    assert_line_index(0)
+    assert_line_around_cursor('1', '')
+    input_keys("\C-_", false)
+    assert_whole_lines(["1", "", "3"])
+    assert_line_index(1)
+    assert_line_around_cursor('', '')
+    input_keys("\C-_", false)
+    assert_whole_lines(["1", "2", "3"])
+    assert_line_index(1)
+    assert_line_around_cursor('2', '')
+    input_keys("\C-_", false)
+    assert_whole_lines(["1", "2", ""])
+    assert_line_index(2)
+    assert_line_around_cursor('', '')
+    input_keys("\C-_", false)
+    assert_whole_lines(["1", "2"])
+    assert_line_index(1)
+    assert_line_around_cursor('2', '')
+  end
+
+  def test_undo_with_many_times
+    str = "a" + "b" * 100
+    input_keys(str, false)
+    100.times { input_keys("\C-_", false) }
+    assert_line_around_cursor('a', '')
+    input_keys("\C-_", false)
+    assert_line_around_cursor('a', '')
+  end
 end
diff --git a/test/reline/yamatanooroti/test_rendering.rb b/test/reline/yamatanooroti/test_rendering.rb
index 9e8d7da78f..37a1c1a193 100644
--- a/test/reline/yamatanooroti/test_rendering.rb
+++ b/test/reline/yamatanooroti/test_rendering.rb
@@ -556,6 +556,19 @@ begin
       EOC
     end
 
+    def test_bracketed_paste_with_undo
+      omit if Reline.core.io_gate.win?
+      start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl}, startup_message: 'Multiline REPL.')
+      write("abc")
+      write("\e[200~def hoge\r\t3\rend\e[201~")
+      write("\C-_")
+      close
+      assert_screen(<<~EOC)
+        Multiline REPL.
+        prompt> abc
+      EOC
+    end
+
     def test_backspace_until_returns_to_initial
       start_terminal(5, 30, %W{ruby -I#{@pwd}/lib #{@pwd}/test/reline/yamatanooroti/multiline_repl}, startup_message: 'Multiline REPL.')
       write("ABC")