Merge branch '227271-move-gitlab-currentsettings-default_branch_name-to-project' into 'master'

Add `Gitlab::CurrentSettings.default_branch_name` fallback to #default_branch

See merge request gitlab-org/gitlab!36231

app/models/concerns/has_repository.rb

@@ -76,7 +76,11 @@ module HasRepository
   end
 
   def default_branch
-    @default_branch ||= repository.root_ref
+    @default_branch ||= repository.root_ref || default_branch_from_preferences
+  end
+
+  def default_branch_from_preferences
+    empty_repo? ? Gitlab::CurrentSettings.default_branch_name : nil
   end
 
   def reload_default_branch

spec/features/projects/show/user_sees_git_instructions_spec.rb

@@ -67,6 +67,7 @@ RSpec.describe 'Projects > Show > User sees Git instructions' do
       before do
         expect(Gitlab::CurrentSettings)
           .to receive(:default_branch_name)
+          .at_least(:once)
           .and_return('example_branch')
 
         sign_in(project.owner)

spec/features/projects/show/user_sees_setup_shortcut_buttons_spec.rb

@@ -63,6 +63,23 @@ RSpec.describe 'Projects > Show > User sees setup shortcut buttons' do
           expect(page).to have_link('Add LICENSE', href: presenter.add_license_path)
         end
       end
+
+      context 'Gitlab::CurrentSettings.default_branch_name is available' do
+        before do
+          expect(Gitlab::CurrentSettings)
+            .to receive(:default_branch_name)
+            .at_least(:once)
+            .and_return('example_branch')
+
+          visit project_path(project)
+        end
+
+        it '"New file" button linked to new file page' do
+          page.within('.project-buttons') do
+            expect(page).to have_link('New file', href: project_new_blob_path(project, 'example_branch'))
+          end
+        end
+      end
     end
   end
 

spec/models/project_spec.rb

@@ -4863,6 +4863,36 @@ RSpec.describe Project do
     end
   end
 
+  describe "#default_branch" do
+    context "with an empty repository" do
+      let_it_be(:project) { create(:project_empty_repo) }
+
+      context "Gitlab::CurrentSettings.default_branch_name is unavailable" do
+        before do
+          expect(Gitlab::CurrentSettings)
+            .to receive(:default_branch_name)
+            .and_return(nil)
+        end
+
+        it "returns that value" do
+          expect(project.default_branch).to be_nil
+        end
+      end
+
+      context "Gitlab::CurrentSettings.default_branch_name is available" do
+        before do
+          expect(Gitlab::CurrentSettings)
+            .to receive(:default_branch_name)
+            .and_return('example_branch')
+        end
+
+        it "returns that value" do
+          expect(project.default_branch).to eq("example_branch")
+        end
+      end
+    end
+  end
+
   describe '#to_ability_name' do
     it 'returns project' do
       project = build(:project_empty_repo)