rehashing regression with compare_by_identity

[ahorek]

Environment

jruby 9.2.1.0-SNAPSHOT (2.5.0) 2018-08-29 dad052a Java HotSpot(TM) 64-Bit Server VM 10.0.1+10 on 10.0.1+10 +jit [mswin32-x86_64]

probably related to the new hash implementation #5215 , @ChrisBr ?

jruby/spec/ruby/core/hash/compare_by_identity_spec.rb

Line 17 in 4e8bb26

it "rehashes internally so that old keys can be looked up" do

1000.times do
  h = {}
  (1..10).each { |k| h[k] = k }
  o = Object.new
  def o.hash; 123; end
  h[o] = 1
  h.compare_by_identity
  puts h[o] == 1
end

another example (fails randomly)
https://travis-ci.org/rails/sprockets/jobs/422225343

Expected Behavior

should always return true

Actual Behavior

true
true
true
false
true
true
true
true
true
true
true
false
true
true
true
true
true
true
true
true
true
true
true
true
true
true
true
false
true
true
true
true
true
true
false
false
true
true
true
true
true
true
...

[ChrisBr]

@ahorek thanks for the bug report.

Confirmed, this does not happen with 9.2.2.0. I will look into it!

[ChrisBr]

@ahorek found the issue and submitted a PR, stay tuned 👍