ActiveRecord::PendingMigrationError 💎 Ruby / Rails

Rails: ActiveRecord::PendingMigrationError — Migrations are pending. To resolve this issue, run: bin/rails db:migrate

The database schema is behind the migration files in the app.

Seen on: Ruby

Meaning

After pulling code with new migrations, deploying, or switching branches, Rails detects unapplied migrations and stops in development/test.

Common causes

  • New migrations not yet run
  • Test database not prepared
  • Branch switch with different migrations
  • Deploy script missing db:migrate

⚡ Quick fix

  1. Run bin/rails db:migrate
  2. For tests: bin/rails db:test:prepare
  3. Add db:migrate to deployment

Detailed fix by platform

Shell

  1. ruby
    bin/rails db:migrate
bin/rails db:migrate:status
RAILS_ENV=test bin/rails db:prepare

How to diagnose

  1. Status — db:migrate:status
  2. Env — Which environment?

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