Use `Gitlab::Access` to protected branch access levels.

1. It makes sense to reuse these constants since we had them duplicated
   in the previous enum implementation. This also simplifies our
   `check_access` implementation, because we can use
   `project.team.max_member_access` directly.

2. Use `accepts_nested_attributes_for` to create push/merge access
   levels. This was a bit fiddly to set up, but this simplifies our code
   by quite a large amount. We can even get rid of
   `ProtectedBranches::BaseService`.

3. Move API handling back into the API (previously in
   `ProtectedBranches::BaseService#translate_api_params`.

4. The protected branch services now return a `ProtectedBranch` rather
   than `true/false`.

5. Run `load_protected_branches` on-demand in the `create` action, to
   prevent it being called unneccessarily.

6. "Masters" is pre-selected as the default option for "Allowed to Push"
   and "Allowed to Merge".

7. These changes were based on a review from @rymai in !5081.

1 files changed, 11 insertions, 5 deletions

diff --git a/spec/factories/protected_branches.rb b/spec/factories/protected_branches.rb
index 24a9b78f0c2..5575852c2d7 100644
--- a/spec/factories/protected_branches.rb
+++ b/spec/factories/protected_branches.rb
@@ -4,20 +4,26 @@ FactoryGirl.define do
     project
 
     after(:create) do |protected_branch|
-      protected_branch.create_push_access_level!(access_level: :masters)
-      protected_branch.create_merge_access_level!(access_level: :masters)
+      protected_branch.create_push_access_level!(access_level: Gitlab::Access::MASTER)
+      protected_branch.create_merge_access_level!(access_level: Gitlab::Access::MASTER)
     end
 
     trait :developers_can_push do
-      after(:create) { |protected_branch| protected_branch.push_access_level.developers! }
+      after(:create) do |protected_branch|
+        protected_branch.push_access_level.update!(access_level: Gitlab::Access::DEVELOPER)
+      end
     end
 
     trait :developers_can_merge do
-      after(:create) { |protected_branch| protected_branch.merge_access_level.developers! }
+      after(:create) do |protected_branch|
+        protected_branch.merge_access_level.update!(access_level: Gitlab::Access::DEVELOPER)
+      end
     end
 
     trait :no_one_can_push do
-      after(:create) { |protected_branch| protected_branch.push_access_level.no_one! }
+      after(:create) do |protected_branch|
+        protected_branch.push_access_level.update!(access_level: Gitlab::Access::NO_ACCESS)
+      end
     end
   end
 end