Fix Time.new keyword arguments on JRuby 10

[johnnyshields]

Summary

• Replace ruby2_keywords approach with explicit **kwargs in new_with_mock_time
• On JRuby 10 (Ruby 3.4 compat), ruby2_keywords doesn't properly forward keyword arguments through new_without_mock_time, causing TypeError: no implicit conversion of Hash into Integer
• This breaks any Rails app using timecop on JRuby 10, since ActiveModel's datetime deserialization calls Time.new with keyword arguments internally

Reproduction

Any Rails 7.2+ app on JRuby 10 that has timecop loaded and reads a datetime column:

TypeError: no implicit conversion of Hash into Integer
# timecop/time_extensions.rb:22:in 'new_with_mock_time'
# activemodel/type/helpers/time_value.rb:93:in 'fast_string_to_time'

Fix

Use explicit **kwargs instead of ruby2_keywords. This works correctly across all Ruby versions and implementations:

def new_with_mock_time(*args, **kwargs)
  if args.empty? && kwargs.empty?
    now
  elsif kwargs.any?
    new_without_mock_time(*args, **kwargs)
  else
    new_without_mock_time(*args)
  end
end

Test plan

• Added test for Time.new with in: keyword argument (Ruby 3.1+)
• Added test for Time.new with positional arguments (regression check)
• All 78 existing tests pass

🤖 Generated with Claude Code

[joshuacronemeyer]

Hi @johnnyshields! Thank you for this thoughtful contribution. I'd love to get this merged. Just a couple tweaks to the tests would help.

Regarding test_time_new_with_keyword_arguments rescue ArgumentError doesn't catch TypeError, which is what older Ruby raises when a hash gets passed as the UTC offset positional argument. So maybe that test needs a conditional so it doesn't run for rubies that don't do keyword arguments

Also, the elsif kwargs.any? branch covers Time.new(in: "+05:00") (kwargs only, no positional args) but there's no test for that specific case. Not a blocker, but worth adding for completeness.

Holding our next release: #444 for this PR