[ruby/irb] Display `show_cmds`'s output in a pager when in TTY

environment
(https://github.com/ruby/irb/pull/647)

This can:

- Make it easier to scroll up and down the commands list
- Avoid pushing up users' previous output
- Allow users to do basic search with `/<word>`

https://github.com/ruby/irb/commit/f94e8a66dd

2 files changed, 28 insertions, 0 deletions

diff --git a/test/irb/test_cmd.rb b/test/irb/test_cmd.rb
index 71df60db14..71d64a0ec2 100644
--- a/test/irb/test_cmd.rb
+++ b/test/irb/test_cmd.rb
@@ -688,6 +688,16 @@ module TestIRB
 
 
   class ShowCmdsTest < CommandTestCase
+    def setup
+      STDIN.singleton_class.define_method :tty? do
+        false
+      end
+    end
+
+    def teardown
+      STDIN.singleton_class.remove_method :tty?
+    end
+
     def test_show_cmds
       out, err = execute_lines(
         "show_cmds\n"
diff --git a/test/irb/yamatanooroti/test_rendering.rb b/test/irb/yamatanooroti/test_rendering.rb
index d2342d6a23..12467b0913 100644
--- a/test/irb/yamatanooroti/test_rendering.rb
+++ b/test/irb/yamatanooroti/test_rendering.rb
@@ -252,6 +252,24 @@ class IRB::RenderingTest < Yamatanooroti::TestCase
     EOC
   end
 
+  def test_show_cmds_with_pager_can_quit_with_ctrl_c
+    write_irbrc <<~'LINES'
+      puts 'start IRB'
+    LINES
+    start_terminal(40, 80, %W{ruby -I#{@pwd}/lib #{@pwd}/exe/irb}, startup_message: 'start IRB')
+    write("show_cmds\n")
+    write("G") # move to the end of the screen
+    write("\C-c") # quit pager
+    write("'foo' + 'bar'\n") # eval something to make sure IRB resumes
+    close
+
+    screen = result.join("\n").sub(/\n*\z/, "\n")
+    # IRB::Abort should be rescued
+    assert_not_match(/IRB::Abort/, screen)
+    # IRB should resume
+    assert_match(/foobar/, screen)
+  end
+
   private
 
   def write_irbrc(content)