Debugger Frozen With Timeout Issue Repro

Steps

1. Run bundle install
2. Run bundle exec rails s
3. Visit http://localhost:3000/ in the browser
4. Once inside the breakpoint, execute the timeout method in the console, which should print Timeout.timeout
5. Type timeout again. But this time, Timeout.timeout wouldn't be printed and the debugger just freezes

Processing by HelloController#hello as HTML
[1, 10] in ~/projects/debug-freeze-issue/app/controllers/hello_controller.rb
     1| class HelloController < ApplicationController
     2|   def hello
     3|     Timeout.timeout(3600) do
=>   4|       binding.b
     5|     end
     6|   end
     7|
     8|   def timeout
     9|     Timeout.timeout(1) { puts "Timeout.timeout" }
    10|   end
=>#0    block in hello at ~/projects/debug-freeze-issue/app/controllers/hello_controller.rb:4
  #1    block {|exc=#<Timeout::Error: Timeout::Error>|} in timeout at ~/.gem/ruby/3.1.2/gems/timeout-0.3.1/lib/timeout.rb:189
  # and 81 frames (use `bt' command for all frames)
(rdbg) timeout
Timeout.timeout
nil
(rdbg) timeout
# just freezes from here

Notes

• Occasionally it'd work fine (1 in 5~6 tries), but most of the time it'd freeze.

• Hit Arrrow Up a few times inside the console could also reproduce it.

  • This is because that key triggers the reline library's call, which uses Timeout.timeout underneath.

  [1, 10] in ~/projects/debug-freeze-issue/app/controllers/hello_controller.rb
      1| class HelloController < ApplicationController
      2|   def hello
      3|     Timeout.timeout(3600) do
  =>   4|       binding.b
      5|     end
      6|   end
      7|
      8|   def timeout
      9|     Timeout.timeout(1) { puts "Timeout.timeout" }
      10|   end
  =>#0    block in hello at ~/projects/debug-freeze-issue/app/controllers/hello_controller.rb:4
  #1    block {|exc=#<Timeout::Error: Timeout::Error>|} in timeout at ~/.gem/ruby/3.1.2/gems/timeout-0.3.1/lib/timeout.rb:189
  # and 81 frames (use `bt' command for all frames)
  (ruby) q!^[[A^[[A^[[A
  # freezes