Glossary

Ruby on Rails Anti-Patterns

A reference dictionary of 30 common failure modes in legacy Rails codebases. Each entry gives a one-line definition, a before/after code example, and a short refactoring path. For step-by-step implementation guides, see the linked Rails Rescue deep dives.

ActiveRecord & Domain

Model-layer anti-patterns: callbacks, associations, query leakage into views.

Callback Hell high
Default Scopes medium
Fat Models high
In-Memory Sorting medium
Law of Demeter Violations medium
Missing inverse_of medium
Polymorphic N+1 Cascades high
STI Abuse medium
View Layer Query Execution high

Database & Transactions

Schema design, migration locks, materialized views, transaction misuse.

HTTP Calls Inside Transactions high
Migration Table Locks high
Missing Materialized Views medium
State Machine Race Conditions high
Unindexed Foreign Keys medium

Infrastructure & Scaling

Sidekiq, connection pools, memory allocators, async API patterns.

ActiveRecord Object Serialization medium
Asset Pipeline Memory Spikes medium
Connection Pool Exhaustion high
Memory-Heavy Rake Enumeration medium
Redis Connection Leaks medium
Rescuing Exception high
Sidekiq Memory Bloat high
Synchronous API Calls high

Testing & Security

Flaky specs, factory bloat, PII encryption, IDOR, thread safety.

Direct Third-Party Mocking medium
Factory Bloat medium
Flaky System Tests medium
Hardcoded Gem Dependencies high
Obsolete Observers medium
Plaintext PII high
Sequential ID Exposure high
Thread-Unsafe Global State high

Inheriting a legacy Rails codebase?

If you recognize several of these anti-patterns in your application, a scoped technical debt audit can quantify the risk and produce a prioritized modernization plan.

Request a Technical Debt Audit