Bug #18686: Regexp supporting unexpected age properties in Ruby < 3.2

• Status: Open
• Priority: Normal
• Assignee: -
• Target version: -
• Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN

[janosch-x (Janosch Müller)]

I've encountered this on GitHub Actions running Ubuntu 20. I cannot reproduce it locally on Darwin/arm64.

It is a weird bug and far from critical, but it might indicate some underlying problem.

I've found that ...

• all Ruby versions below 3.1 allow /\p{age=14.0}/
  • this is unexpected because age 14 was only added in Ruby 3.2
  • Ruby seems to parse this as age=10.0, at least it matches exactly these codepoints
• all Ruby versions below 3.2 allow some unexpected values for age
  • allowed values are e.g. age=21.0, age=41.0, age=99.0 (depending on Ruby version)
  • on Ruby 3.1, age=99.0 matches exactly the same codepoints as age=11.0
• ruby-head doesn't seem to allow unexpected age values (i've only tested values ending in .0)

I've set up a minimal reproduction here:

https://github.com/jaynetics/ruby_age_property_bug_repro

with the unexpected results visible here:

https://github.com/jaynetics/ruby_age_property_bug_repro/actions/runs/2115522407

and here:

https://github.com/jaynetics/ruby_age_property_bug_repro/actions/runs/2116785501

CC @duerst (Martin Dürst)