WA-VERIFY-083: Assess Mongoid 8 upgrade readiness — identify all breaking changes in workarea-core

[kitcommerce]

Summary

PR #1065 (WA-VERIFY-079) confirmed that both Rails 7.1 and Rails 7.2 appraisal gemfiles cannot bundle due to Mongoid 7.x's hard activemodel < 7.1 constraint. Issue #690 (WA-RAILS7-004) is the blocker.

Before attempting the Mongoid 8 upgrade (#690), we need a comprehensive assessment of what changes are required. This issue produces that assessment without making code changes.

Approach

# Review Mongoid 8 changelog for breaking changes
# https://docs.mongodb.com/mongoid/current/release-notes/mongoid-8.0/

# Audit workarea-core for Mongoid 7-specific API usage
grep -r 'Mongoid::' core/app/ core/lib/ --include='*.rb' | grep -v '_test.rb' | sort | uniq -c | sort -rn | head -30

# Check for deprecated Mongoid 7 patterns
grep -rn 'pluck\|slice\|first_or_create\|find_or_create_by' core/app/ --include='*.rb' | head -20

Deliverables

• Categorized list of Mongoid 7 → 8 API changes used in workarea-core
• Estimate of effort (number of files, change types)
• Recommended upgrade approach (big-bang vs incremental)
• Notes on mongoid-compatibility gem as optional bridge

Acceptance Criteria

• notes/mongoid8-upgrade-assessment-YYYY-MM-DD.md created with findings
• Breaking changes categorized by severity
• PR opened with assessment document

Client Impact

Assessment only — no code changes. Follow-on issue for actual upgrade.

Related

• Issue WA-RAILS7-004: Mongoid 8.x upgrade — implement changes from research doc #690 (WA-RAILS7-004 — Mongoid 8 upgrade, currently blocked:dependency)
• PR verify: Rails 7.1 appraisal smoke test (WA-VERIFY-079) #1065 (WA-VERIFY-079 — confirms Mongoid 7/Rails 7.1 incompatibility)
• Issue WA-FWD: Upgrade Mongoid to support Rails 7.1/7.2 appraisals #841 (WA-FWD — Mongoid 8 upgrade, changes-requested)