MONGOID-5694 Fix validations on associations - DO NOT MERGE

lib/mongoid/persistable/updatable.rb

@@ -38,8 +38,16 @@ def update_attribute(name, value)
       #
       # @return [ true | false ] True if validation passed, false if not.
       def update(attributes = {})
-        assign_attributes(attributes)
-        save
+        self.class.with_session do |session|
+          session.with_transaction do
+            assign_attributes(attributes)
+            save.tap do |result|
+              session.abort_transaction unless result
+            end
+          end
+        end
+      rescue StandardError => e
+        false
       end
       alias :update_attributes :update
 

spec/integration/validations_spec.rb

@@ -0,0 +1,41 @@
+# rubocop:todo all
+# frozen_string_literal: true
+
+require 'spec_helper'
+require_relative './validations_spec_models'
+
+describe 'validations' do
+
+  context 'when validating presence of has_and_belongs_to_many association' do
+    let(:company) { ValidationsSpecModels::Company.create! }
+    let(:client) { ValidationsSpecModels::Client.create!(companies: [company]) }
+
+    context 'when updating the association' do
+      it 'raises an error' do
+        expect { client.update!(companies: []) }.to raise_error(Mongoid::Errors::Validations)
+      end
+
+      it 'does not persist the changes' do
+        client.update!(companies: []) rescue nil
+        expect(client.reload.companies).not_to be_empty
+      end
+    end
+  end
+
+
+  context 'when validating presence of has_many association' do
+    let(:apartment) { ValidationsSpecModels::Apartment.create! }
+    let(:building) { ValidationsSpecModels::Building.create!(apartments: [apartment]) }
+
+    context 'when updating the association' do
+      it 'raises an error' do
+        expect { building.update!(apartments: []) }.to raise_error(Mongoid::Errors::Validations)
+      end
+
+      it 'does not persist the changes' do
+        building.update!(apartments: []) rescue nil
+        expect(building.reload.apartments).not_to be_empty
+      end
+    end
+  end
+end

spec/integration/validations_spec_models.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+module ValidationsSpecModels
+  class Company
+    include Mongoid::Document
+  end
+
+  class Client
+    include Mongoid::Document
+
+    has_and_belongs_to_many :companies, class_name: 'ValidationsSpecModels::Company'
+    validates :companies, presence: true
+  end
+
+  class Building
+    include Mongoid::Document
+    has_many :apartments, class_name: 'ValidationsSpecModels::Apartment'
+    validates :apartments, presence: true
+  end
+
+  class Apartment
+    include Mongoid::Document
+    belongs_to :building, class_name: 'ValidationsSpecModels::Building'
+  end
+end