iron-laws

Iron Laws

Overview

These 22 rules are NEVER violated. If code would violate them, STOP and explain before proceeding.

Active Record (7 laws)

1. Decimal for Money — NEVER use float for money — use decimal or integer (cents)
2. Parameterized Queries — ALWAYS use parameterized queries — never interpolate user input into SQL strings
3. Eager Loading — USE includes/preload for associations — avoids N+1 queries
4. Commit-Safe Enqueueing in Active Record — IN Active Record code, use after_commit not after_save when enqueueing jobs that depend on committed data
5. Transaction Boundaries — WRAP multi-step operations in transactions — use ActiveRecord::Base.transaction
6. No Validation Bypass — NO update_columns, update_column, or save(validate: false) in normal flows
7. No default_scope — NO default_scope — use explicit named scopes only

Sidekiq (4 laws)

1. Idempotent Jobs — Jobs MUST be idempotent — safe to retry
2. JSON-Safe Arguments — Args use JSON-safe types only — no symbols, no Ruby objects, no procs
3. No ORM Objects in Args — NEVER store ORM objects in args — store IDs, not records
4. Commit-Safe Enqueueing — ALWAYS enqueue jobs after commit using the active ORM or transaction hook — not after_save or inline before commit

Security (4 laws)

1. No Ruby Eval — NO Ruby eval/instance_eval/class_eval with user input — code injection vulnerability. Shell eval of trusted helper output is out of scope
2. Explicit Authorization — AUTHORIZE in EVERY controller action — do not trust before_action alone
3. No Unsafe HTML — NEVER use html_safe or raw with untrusted content — XSS vulnerability
4. No SQL Concatenation — NO SQL string concatenation — always use parameterized queries

Ruby (3 laws)

1. method_missing Requires respond_to_missing? — NO method_missing without respond_to_missing? — breaks introspection
2. Supervise Background Processes — SUPERVISE ALL BACKGROUND PROCESSES — use proper process managers in production
3. No Rescue Exception — DON'T rescue Exception (in begin/rescue or Rails rescue_from) — catches SystemExit/SignalException. Bare rescue defaults to StandardError, not a Law 18 violation.