rails-db-schema-load-over-migrate

Detects GitHub Actions jobs that initialize an ephemeral Rails test database by replaying all migrations with rails db:migrate, and recommends loading the schema directly instead.

Why This Matters

In CI, test databases are ephemeral—they are created fresh for each run and discarded afterward. Running db:migrate on every CI run executes every migration in sequence, which can take significantly longer than loading the current schema directly.

For large Rails applications with hundreds of migrations, the difference can be minutes per CI run.

Detection

The rule fires when a job meets all of the following:

1. Rails/Ruby job: uses ruby/setup-ruby, or runs bundle install, bundle exec, rails, rake, rspec, or bin/rails.
2. Ephemeral database: declares a services entry for PostgreSQL, MySQL, or MariaDB.
3. Test context: sets RAILS_ENV=test or RACK_ENV=test, or runs rails test, rake test, rspec, or bundle exec rspec.
4. Uses db:migrate: runs rails db:migrate, bin/rails db:migrate, bundle exec rails db:migrate, rake db:migrate, or bundle exec rake db:migrate.

Not Triggered When

• The job or workflow name suggests migration verification intent (e.g. contains migration, schema check, rollback, upgrade, compatibility).
• The command is a migration-variation such as db:migrate:redo, db:migrate:down, db:migrate:up, db:rollback, db:forward, or db:abort_if_pending_migrations.

Resolution

On Rails 6.1 and newer, db:schema:load loads either db/schema.rb or db/structure.sql, so it replaces both the old schema and structure loaders:

- bundle exec rails db:migrate
+ bundle exec rails db:schema:load

On Rails older than 6.1, use db:schema:load when the project uses db/schema.rb, and db:structure:load when it uses db/structure.sql:

- bundle exec rails db:migrate
+ bundle exec rails db:structure:load

The suggestion text mentions both commands, so no Rails version detection is required.

Keep db:migrate only in jobs that intentionally test migration correctness, such as a “schema check” or “migration verification” workflow.

Severity

• High — when ephemeral DB service, test context, and db:migrate are all detected.