Handle creating a nested group on MySQL correctly

Since we don't support nested groups on MySQL, raise an error
explaining that on import instead of trying anyway.

app/services/groups/nested_create_service.rb

@@ -15,6 +15,10 @@ module Groups
         return group
       end
 
+      if group_path.include?('/') && !Group.supports_nested_groups?
+        raise 'Nested groups are not supported on MySQL'
+      end
+
       create_group_path
     end
 

spec/lib/gitlab/bare_repository_importer_spec.rb

@@ -2,13 +2,14 @@ require 'spec_helper'
 
 describe Gitlab::BareRepositoryImporter, repository: true do
   subject(:importer) { described_class.new('default', project_path) }
-  let(:project_path) { 'a-group/a-sub-group/a-project' }
+
   let!(:admin) { create(:admin) }
 
   before do
     allow(described_class).to receive(:log)
   end
 
+  shared_examples 'importing a repository' do
     describe '.execute' do
       it 'creates a project for a repository in storage' do
         FileUtils.mkdir_p(File.join(TestEnv.repos_path, "#{project_path}.git"))
@@ -49,12 +50,10 @@ describe Gitlab::BareRepositoryImporter, repository: true do
       end
 
       it 'skips importing when the project already exists' do
-      group = create(:group, path: 'a-group')
-      subgroup = create(:group, path: 'a-sub-group', parent: group)
-      project = create(:project, path: 'a-project', namespace: subgroup)
+        project = create(:project, path: 'a-project', namespace: existing_group)
 
         expect(importer).not_to receive(:create_project)
-      expect(importer).to receive(:log).with(" * #{project.name} (a-group/a-sub-group/a-project) exists")
+        expect(importer).to receive(:log).with(" * #{project.name} (#{project_path}) exists")
 
         importer.create_project_if_needed
       end
@@ -65,4 +64,37 @@ describe Gitlab::BareRepositoryImporter, repository: true do
         expect(Project.find_by_full_path(project_path)).not_to be_nil
       end
     end
+  end
+
+  context 'with subgroups', :nested_groups do
+    let(:project_path) { 'a-group/a-sub-group/a-project' }
+
+    let(:existing_group) do
+      group = create(:group, path: 'a-group')
+      create(:group, path: 'a-sub-group', parent: group)
+    end
+
+    it_behaves_like 'importing a repository'
+  end
+
+  context 'without subgroups' do
+    let(:project_path) { 'a-group/a-project' }
+    let(:existing_group) { create(:group, path: 'a-group') }
+
+    it_behaves_like 'importing a repository'
+  end
+
+  context 'when subgroups are not available' do
+    let(:project_path) { 'a-group/a-sub-group/a-project' }
+
+    before do
+      expect(Group).to receive(:supports_nested_groups?) { false }
+    end
+
+    describe '#create_project_if_needed' do
+      it 'raises an error' do
+        expect { importer.create_project_if_needed }.to raise_error('Nested groups are not supported on MySQL')
+      end
+    end
+  end
 end

spec/services/groups/nested_create_service_spec.rb

@@ -2,10 +2,61 @@ require 'spec_helper'
 
 describe Groups::NestedCreateService do
   let(:user) { create(:user) }
-  let(:params) { { group_path: 'a-group/a-sub-group' } }
 
   subject(:service) { described_class.new(user, params) }
 
+  shared_examples 'with a visibility level' do
+    it 'creates the group with correct visibility level' do
+      allow(Gitlab::CurrentSettings.current_application_settings)
+        .to receive(:default_group_visibility) { Gitlab::VisibilityLevel::INTERNAL }
+
+      group = service.execute
+
+      expect(group.visibility_level).to eq(Gitlab::VisibilityLevel::INTERNAL)
+    end
+
+    context 'adding a visibility level ' do
+      it 'overwrites the visibility level' do
+        service = described_class.new(user, params.merge(visibility_level: Gitlab::VisibilityLevel::PRIVATE))
+
+        group = service.execute
+
+        expect(group.visibility_level).to eq(Gitlab::VisibilityLevel::PRIVATE)
+      end
+    end
+  end
+
+  describe 'without subgroups' do
+    let(:params) { { group_path: 'a-group' } }
+
+    before do
+      allow(Group).to receive(:supports_nested_groups?) { false }
+    end
+
+    it 'creates the group' do
+      group = service.execute
+
+      expect(group).to be_persisted
+    end
+
+    it 'returns the group if it already existed' do
+      existing_group = create(:group, path: 'a-group')
+
+      expect(service.execute).to eq(existing_group)
+    end
+
+    it 'raises an error when tring to create a subgroup' do
+      service = described_class.new(user, group_path: 'a-group/a-sub-group')
+
+      expect { service.execute }.to raise_error('Nested groups are not supported on MySQL')
+    end
+
+    it_behaves_like 'with a visibility level'
+  end
+
+  describe 'with subgroups', :nested_groups do
+    let(:params) { { group_path: 'a-group/a-sub-group' } }
+
     describe "#execute" do
       it 'returns the group if it already existed' do
         parent = create(:group, path: 'a-group', owner: user)
@@ -14,14 +65,14 @@ describe Groups::NestedCreateService do
         expect(service.execute).to eq(child)
       end
 
-    it 'reuses a parent if it already existed', :nested_groups do
+      it 'reuses a parent if it already existed' do
         parent = create(:group, path: 'a-group')
         parent.add_owner(user)
 
         expect(service.execute.parent).to eq(parent)
       end
 
-    it 'creates group and subgroup in the database', :nested_groups do
+      it 'creates group and subgroup in the database' do
         service.execute
 
         parent = Group.find_by_full_path('a-group')
@@ -31,23 +82,7 @@ describe Groups::NestedCreateService do
         expect(child).not_to be_nil
       end
 
-    it 'creates the group with correct visibility level' do
-      allow(Gitlab::CurrentSettings.current_application_settings)
-        .to receive(:default_group_visibility) { Gitlab::VisibilityLevel::INTERNAL }
-
-      group = service.execute
-
-      expect(group.visibility_level).to eq(Gitlab::VisibilityLevel::INTERNAL)
-    end
-
-    context 'adding a visibility level ' do
-      let(:params) { { group_path: 'a-group/a-sub-group', visibility_level: Gitlab::VisibilityLevel::PRIVATE } }
-
-      it 'overwrites the visibility level' do
-        group = service.execute
-
-        expect(group.visibility_level).to eq(Gitlab::VisibilityLevel::PRIVATE)
-      end
+      it_behaves_like 'with a visibility level'
     end
   end
 end