Respect Group's default branch name when present

app/models/concerns/has_repository.rb

@@ -84,7 +84,11 @@ module HasRepository
   end
 
   def default_branch_from_preferences
-    empty_repo? ? Gitlab::CurrentSettings.default_branch_name : nil
+    return unless empty_repo?
+
+    group_branch_default_name = group&.default_branch_name if respond_to?(:group)
+
+    group_branch_default_name || Gitlab::CurrentSettings.default_branch_name
   end
 
   def reload_default_branch

app/models/group.rb

@@ -552,6 +552,10 @@ class Group < Namespace
     owners.first || parent&.default_owner || owner
   end
 
+  def default_branch_name
+    namespace_settings&.default_branch_name
+  end
+
   def access_level_roles
     GroupMember.access_level_roles
   end

app/services/projects/create_service.rb

@@ -147,7 +147,7 @@ module Projects
 
     def create_readme
       commit_attrs = {
-        branch_name:  Gitlab::CurrentSettings.default_branch_name.presence || 'master',
+        branch_name: @project.default_branch || 'master',
         commit_message: 'Initial commit',
         file_path: 'README.md',
         file_content: "# #{@project.name}\n\n#{@project.description}"

app/views/projects/empty.html.haml

 - @content_class = "limit-container-width" unless fluid_layout
-- default_branch_name = Gitlab::CurrentSettings.default_branch_name.presence || "master"
+- default_branch_name = @project.default_branch || "master"
 - breadcrumb_title _("Details")
 - page_title _("Details")
 

changelogs/unreleased/251963-respect-group-s-default-branch-name-when-present.yml

+---
+title: Respect Group's default branch name when present
+merge_request: 44370
+author:
+type: changed

spec/models/group_spec.rb

@@ -1506,6 +1506,28 @@ RSpec.describe Group do
     end
   end
 
+  describe "#default_branch_name" do
+    context "group.namespace_settings does not have a default branch name" do
+      it "returns nil" do
+        expect(group.default_branch_name).to be_nil
+      end
+    end
+
+    context "group.namespace_settings has a default branch name" do
+      let(:example_branch_name) { "example_branch_name" }
+
+      before do
+        expect(group.namespace_settings)
+          .to receive(:default_branch_name)
+          .and_return(example_branch_name)
+      end
+
+      it "returns the default branch name" do
+        expect(group.default_branch_name).to eq(example_branch_name)
+      end
+    end
+  end
+
   describe '#default_owner' do
     let(:group) { build(:group) }
 

spec/models/project_spec.rb

@@ -4979,15 +4979,21 @@ RSpec.describe Project do
     context "with an empty repository" do
       let_it_be(:project) { create(:project_empty_repo) }
 
-      context "Gitlab::CurrentSettings.default_branch_name is unavailable" do
+      context "group.default_branch_name is available" do
+        let(:project_group) { create(:group) }
+        let(:project) { create(:project, path: 'avatar', namespace: project_group) }
+
         before do
           expect(Gitlab::CurrentSettings)
+            .not_to receive(:default_branch_name)
+
+          expect(project.group)
             .to receive(:default_branch_name)
-            .and_return(nil)
+            .and_return('example_branch')
         end
 
-        it "returns that value" do
-          expect(project.default_branch).to be_nil
+        it "returns the group default value" do
+          expect(project.default_branch).to eq("example_branch")
         end
       end
 
@@ -4995,11 +5001,23 @@ RSpec.describe Project do
         before do
           expect(Gitlab::CurrentSettings)
             .to receive(:default_branch_name)
-            .and_return('example_branch')
+            .and_return(example_branch_name)
         end
 
-        it "returns that value" do
-          expect(project.default_branch).to eq("example_branch")
+        context "is missing or nil" do
+          let(:example_branch_name) { nil }
+
+          it "returns nil" do
+            expect(project.default_branch).to be_nil
+          end
+        end
+
+        context "is present" do
+          let(:example_branch_name) { "example_branch_name" }
+
+          it "returns the expected branch name" do
+            expect(project.default_branch).to eq(example_branch_name)
+          end
         end
       end
     end