[bug?] Bypassing validations on update

[zbrunoneves]

Let's say I have an application with a has_and_belongs_to_many relation between a Client model and a Company model.
In the Client model there is a validation to make sure the object is associated with at least one company (companies cannot be blank).
The thing is, when I try to update a client with an empty list of companies, despite raising a validation error message, the invalid model is updated in the database.
Is this an expected behavior?

One can reproduce it by running the following code:

class Company
  include Mongoid::Document

  field :name, type: String
end

class Client
  include Mongoid::Document

  field :name, type: String

  has_and_belongs_to_many :companies, class_name: 'Company'

  validates :companies, presence: true
end

c = Client.first
c.update!(companies: []) # raises error but updates document

[alexbevi]

Hi @zbrunoneves, and thanks for reporting this! I've filed MONGOID-5694 to have the team review this and identify next steps.

[roloand]

@alexbevi Sorry if this isn't according to protocol, I wanted to report, as I've done some testing while trying to upgrade Mongoid, this issue affects 7.3.5, 7.4.x, and 7.5.x

[alexbevi]

Thanks for the report @roloand - I've updated the Affects Version/s on MONGOID-5694 accordingly. This ticket is still on our radar but won't be picked up until after we release Mongoid 9.0 (which should be happening soon).