WA-VERIFY-074: Check Ruby 3.5 compatibility (keyword warnings, frozen string changes)

[kitcommerce]

Summary

Ruby 3.5 is on the horizon. Brakeman's EOL warning (Ruby 3.2 expires 2026-03-31) flags an upcoming constraint. Before widening the required_ruby_version upper bound beyond 3.5, verify compatibility.

Approach

# Check if Ruby 3.5 is available in CI/rbenv
rbenv install --list | grep 3.5

# Run the test suite under Ruby 3.5 if available (or 3.4 as proxy)
RBENV_VERSION=3.4.2 rbenv exec bundle exec rake core_test
RBENV_VERSION=3.4.2 rbenv exec bundle exec rake admin_test
RBENV_VERSION=3.4.2 rbenv exec bundle exec rake storefront_test

# Check for Ruby 3.5-specific deprecations (keyword args, pattern matching)
RBENV_VERSION=3.4.2 rbenv exec bundle exec ruby -W admin/config/application.rb 2>&1 | grep -i warn | head -20

Acceptance Criteria

• Ruby 3.4 full test suite run attempted; results documented
• Any SyntaxWarning, TypeError, or NoMethodError regressions identified
• Recommendation on whether to widen required_ruby_version upper bound to < 4.0
• Follow-up issues filed for any failures

Client Impact

None (verification only). Any gemspec changes would be a separate issue.

Notes

Companion to WA-VERIFY-073 (gemspec ruby version audit). The current upper bound < 3.5.0 was chosen conservatively; this issue tests whether it can be widened.

[kitcommerce]

PR opened: #1059

Ruby 3.4.2 tested. Zero syntax errors across ~1,250 app files. No keyword arg, frozen string, or SyntaxWarning regressions. Test suite blocked by MongoDB unavailability (infrastructure, not Ruby). Full findings in notes/ruby35-compat-2026-03-17.md. Recommendation: widen required_ruby_version to < 3.6.0 once CI with services confirms.