Unsafe foreign keys with create_table

[markbrown4]

It doesn't appear like adding foreign keys within create_table are detected as unsafe. e.g.

class Test < ActiveRecord::Migration[6.1]
  def change
    create_table :test do |t|
      t.references :user, foreign_key: true
    end
  end
end

As I understand it this would hold a lock on the users table.

I couldn't find a way to detect this with a custom check. This monkey patch seems to work but I'm wondering if this should make it's way into Strong Migrations itself or if there's a better way to achieve it.

# Prevent foreign keys being defined with t.references e.g.
# t.references :x, foreign_key: true
# t.references :x, foreign_key: {}

class ActiveRecord::ConnectionAdapters::ReferenceDefinition
  alias_method :__add_to__, :add_to
  def add_to(table)
    if foreign_key
      raise ArgumentError
    end
    __add_to__(table)
  end
end

# Prevent foreign keys being defined within column definitions e.g.
# t.bigint :x_id, foreign_key: true
# t.bigint :x_id, foreign_key: {}

class ActiveRecord::ConnectionAdapters::TableDefinition
  alias_method :__column__, :column
  def column(name, type, index: nil, **options)
    if options[:foreign_key]
      raise ArgumentError
    end
    __column__(name, type, index: index, **options)
  end
end

Thanks! 🙏

[ankane]

Hey @markbrown4, check out #170 for previous discussion about adding foreign keys to new tables.