Infinite loop detected in this code snippet

[terryyin]

def x
  a b {
    %(
-
    )
  }
end

[tejasbubane]

I cannot reproduce this on rubocop 0.45.0, rather got this offense:

Offenses:

rubocop_bug_test.rb:3:8: C: Style/SpaceInsideBlockBraces: Space missing inside {.
  a b { ...


1 file inspected, 1 offense detected

[rrosenblum]

@tejasbubane I was able to reproduce on RuboCop 0.45.0 running rubocop -a. The offense is registered when rubocop is run on the file. The infinite loop comes from the auto-correction.

Here is the stack trace

  work/rubocop/lib/rubocop/runner.rb:233:in `check_for_infinite_loop'
  work/rubocop/lib/rubocop/runner.rb:216:in `block in iterate_until_no_changes'
  work/rubocop/lib/rubocop/runner.rb:215:in `loop'
  work/rubocop/lib/rubocop/runner.rb:215:in `iterate_until_no_changes'
  work/rubocop/lib/rubocop/runner.rb:186:in `do_inspection_loop'
  work/rubocop/lib/rubocop/runner.rb:101:in `block in file_offenses'
  work/rubocop/lib/rubocop/runner.rb:111:in `file_offense_cache'
  work/rubocop/lib/rubocop/runner.rb:99:in `file_offenses'
  work/rubocop/lib/rubocop/runner.rb:90:in `process_file'
  work/rubocop/lib/rubocop/runner.rb:68:in `block in each_inspected_file'
  work/rubocop/lib/rubocop/runner.rb:65:in `each'
  work/rubocop/lib/rubocop/runner.rb:65:in `reduce'
  work/rubocop/lib/rubocop/runner.rb:65:in `each_inspected_file'
  work/rubocop/lib/rubocop/runner.rb:57:in `inspect_files'
  work/rubocop/lib/rubocop/runner.rb:36:in `run'
  work/rubocop/lib/rubocop/cli.rb:72:in `execute_runner'
  work/rubocop/lib/rubocop/cli.rb:27:in `run'

[rrosenblum]

I was able to narrow this down to a single cop. Running rubocop -a --only Style/SpaceInsideBlockBraces will produce the infinite loop. I wasn't able to do much more digging than this yet. It looks like there might be some auto-correct tests missing from that cop.

[terryyin]

Thanks!