When working with Rails migrations across git branches:

1. You run migrations on a feature branch
2. Switch back to main
3. Run db:migrate - Rails dumps schema including changes from the other branch
4. You can't rollback because the migration files don't exist in current branch

Usual workaround: Switch to the other branch, rollback, switch back. Tedious.

Mighost automatically captures migration file contents when they run, enabling rollback even when the original file is not present. It uses a 3-tier recovery strategy:

1. Stored snapshots — captured at migration time into a local SQLite file
2. Git history — searches across all branches
3. Worktree recovery — finds files in other git worktrees

Add to your Gemfile:

gem 'mighost', group: [:development, :test]

Then run:

bundle install
rails generate mighost:install

Add .mighost.sqlite3 to your .gitignore.

Requires Ruby >= 3.1 and Rails 6.1–8.1.

rails mighost:status

# Interactive (with confirmation)
rails mighost:rollback

# Force (no confirmation)
FORCE=1 rails mighost:rollback

# Specific version
rails mighost:rollback VERSION=20240115123456

If you install Mighost on an existing project:

rails mighost:scan

VERSION=20240115123456       # Single version
VERSION=20240110..20240120   # Inclusive range
VERSION=20240110..           # From version onwards
VERSION=..20240120           # Up to version

# config/initializers/mighost.rb
Mighost.configure do |config|
  # Path to SQLite file (relative to Rails.root)
  config.storage_path = ".mighost.sqlite3"

  # Auto-capture on migrate
  config.auto_capture = true

  # Store git metadata
  config.store_git_metadata = true

  # Enable/disable (disabled in production by default)
  config.enabled = !Rails.env.production?
end

By default, Mighost outputs plain, uncolored text. For rich, colorized output with tables, emojis, and git enrichment, use the railbow gem:

gem 'railbow'

Railbow automatically detects Mighost and enhances its output.

Mighost exposes a stable API for programmatic access:

# Detect orphaned migrations
Mighost::API.orphaned_migrations                  # => [OrphanedMigration, ...]

# Find snapshots
Mighost::API.find_snapshot("20240115123456")       # => Snapshot or nil
Mighost::API.find_or_recover_snapshot("20240115")  # => Snapshot (with git/worktree fallback)

# Scan and recover
Mighost::API.scan!(rescan: false)                  # => {captured:, git_recovered:, ...}

# Rollback
Mighost::API.rollback_version!("20240115123456")   # raises on failure

Mighost uses a pluggable UI adapter for output. Replace it to customize formatting:

# In your railtie or initializer:
Mighost.ui = YourCustomUI.new

The adapter must implement: render_orphans, render_records, render_recoverable_list, render_scan_details, render_scan_results, render_dismiss_preview, render_dismiss_remaining, render_dismissed_list, confirm?, confirm_each?, confirm_dismiss?, success, error, warning, info, hint. See Mighost::PlainUI for the reference implementation.

1. Capture: When you run db:migrate, Mighost hooks into ActiveRecord::Migrator and stores the migration file content along with git metadata (branch, SHA) in a local SQLite file.

2. Detect: mighost:status compares schema_migrations table with actual migration files to find orphans.

3. Recover: For missing files, Mighost searches stored snapshots, git history (all branches), and other git worktrees.

4. Rollback: Writes recovered content to a temp file, loads it, calls the down method, then removes the version from schema_migrations.

• Irreversible migrations: If the migration raises ActiveRecord::IrreversibleMigration, Mighost can't help.
• Model dependencies: If your migration references models/classes that don't exist in the current branch, the rollback may fail.
• Manual SQL changes: If someone manually modified the database, rollback might not work correctly.
• Trust: Recovered migration code (from snapshots, git history, or worktrees) is executed with the same trust as your own migrations — it is code from your repository, run by you.

Bug reports and pull requests are welcome on GitHub. Run bundle exec rake (specs + standardrb) before submitting.

MIT License. See LICENSE.