Beware of using default scope

Default Scope is used to apply scope to all queries by default.

class User < ActiveRecord::Base
  default_scope {where(state: 'pending')}
end

User.all #=> User Load (0.2ms)  SELECT "users".* FROM "users"  WHERE "users"."status" = 'pending'

Lets add one more scope

class User < ActiveRecord::Base
  default_scope {where(state: 'pending')}
  scope :active, ->{where(state: 'active')}
end

User.active #=> SELECT "users".* FROM "users"  WHERE "users"."status" = 'pending' AND "users"."status" = 'active'
User.where(state: 'active')  #=> SELECT "users".* FROM "users"  WHERE "users"."status" = 'pending' AND "users"."status" = 'active'

As you can see It hasn't override default scope which we thought it should because we are scoping on same column

So if you have default scope and want to remove default scope behaviour from other scope you can user unscope, unscoped or rewhere and except

class User < ActiveRecord::Base
  default_scope {where(state: 'pending')} 
  scope :active, ->{unscope(where: :state).where(state: 'active')}
end

class User < ActiveRecord::Base
  default_scope {where(state: 'pending')}
  scope :active, ->{where(state: 'active')}
end

User.unscoped.active #=> SELECT "users".* FROM "users"  WHERE "users"."state" = 'active'
User.rewhere(state: 'active') #=> SELECT "users".* FROM "users"  WHERE "users"."state" = 'active'
User.except(:default_scope).active #=> SELECT "users".* FROM "users"  WHERE "users"."state" = 'active'

You can find more detail here
https://github.com/rails/rails/issues/13875#issuecomment-35430595

So Beware of using Default Scope.