Change merge request diff creation from callback to part of the service

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/merge_requests_controller.rb

@@ -88,7 +88,6 @@ class Projects::MergeRequestsController < Projects::ApplicationController
         @merge_request.merge_request_diff
       end
 
-
     respond_to do |format|
       format.html { define_discussion_vars }
       format.json { render json: { html: view_to_html_string("projects/merge_requests/show/_diffs") } }

app/models/merge_request.rb

@@ -15,7 +15,6 @@ class MergeRequest < ActiveRecord::Base
 
   serialize :merge_params, Hash
 
-  before_validation :ensure_merge_request_diff, on: :create, unless: :importing?
   after_update :update_merge_request_diff
 
   delegate :commits, :real_size, to: :merge_request_diff, prefix: nil
@@ -283,10 +282,6 @@ class MergeRequest < ActiveRecord::Base
     end
   end
 
-  def ensure_merge_request_diff
-    merge_request_diff || merge_request_diffs.build
-  end
-
   def create_merge_request_diff
     merge_request_diffs.create
   end

app/services/merge_requests/create_service.rb

@@ -16,6 +16,7 @@ module MergeRequests
       merge_request.target_project ||= source_project
       merge_request.author = current_user
       merge_request.merge_params['force_remove_source_branch'] = force_remove_source_branch
+      merge_request.merge_request_diffs.build
 
       if merge_request.save
         merge_request.update_attributes(label_ids: label_params)

spec/factories/merge_requests.rb

@@ -68,5 +68,11 @@ FactoryGirl.define do
     factory :closed_merge_request, traits: [:closed]
     factory :reopened_merge_request, traits: [:reopened]
     factory :merge_request_with_diffs, traits: [:with_diffs]
+
+    after :create do |merge_request|
+      unless merge_request.merge_request_diff
+        merge_request.create_merge_request_diff
+      end
+    end
   end
 end

spec/models/merge_request_diff_spec.rb

@@ -11,9 +11,10 @@ describe MergeRequestDiff, models: true do
   end
 
   describe 'create new record' do
-    subject { create(:merge_request) }
+    subject { create(:merge_request).merge_request_diff }
 
     it { expect(subject).to be_valid }
+    it { expect(subject).to be_persisted }
     it { expect(subject.commits.count).to eq(5) }
     it { expect(subject.diffs.count).to eq(8) }
   end