diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index 6e7dfd7c8af..4d8429dd554 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -60,6 +60,10 @@ class Projects::MergeRequestsController < Projects::ApplicationController
   end
 
   def new
+    params[:merge_request] ||= ActionController::Parameters.new(
+      source_project: @project
+    )
+
     @merge_request = MergeRequest.new(merge_request_params)
     @merge_request.source_project = @project unless @merge_request.source_project
     @merge_request.target_project ||= (@project.forked_from_project || @project)
diff --git a/config/environments/development.rb b/config/environments/development.rb
index e4c7649fda0..356e26bd68c 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -19,9 +19,6 @@ Gitlab::Application.configure do
   # Only use best-standards-support built into browsers
   config.action_dispatch.best_standards_support = :builtin
 
-  # Raise exception on mass assignment protection for Active Record models
-  config.active_record.mass_assignment_sanitizer = :strict
-
   # Do not compress assets
   config.assets.compress = false
 
diff --git a/config/environments/test.rb b/config/environments/test.rb
index 3860dc5c74c..25b082b98da 100644
--- a/config/environments/test.rb
+++ b/config/environments/test.rb
@@ -26,9 +26,6 @@ Gitlab::Application.configure do
   # ActionMailer::Base.deliveries array.
   config.action_mailer.delivery_method = :test
 
-  # Raise exception on mass assignment protection for Active Record models
-  # config.active_record.mass_assignment_sanitizer = :strict
-
   # Print deprecation notices to the stderr
   config.active_support.deprecation = :stderr