Backend Architecture

CE/EE Code Separation

• CE code (outside ee/) must not directly reference EE:: namespaced classes
• EE extensions use prepend_mod pattern in CE files
• If CE code needs EE-aware behavior, use prepend_mod hooks or Gitlab.ee? guards
• Flag direct references to EE:: namespaced classes in CE code (prevents FOSS build failures)

ActiveRecord Callbacks

• Callbacks should only modify data on the current model, not associated records
• Question if callback logic should be in a service layer instead
• Flag callbacks with side effects (external API calls, updating other records, complex business logic)
• Flag bulk operations on associated records in callbacks (performance concern as associations grow)
• Acceptable uses: data normalization on current model only (trimming whitespace, setting defaults)

Authorization

• Before changing authorization logic, read the existing authorize! / authorize_admin! call and verify what permission it currently enforces; the required fix may be documentation- or test-only with no code change needed