Fix preselected namespace when creating a project

app/helpers/namespaces_helper.rb

 module NamespacesHelper
+  def namespace_id_from(params)
+    params.dig(:project, :namespace_id) || params[:namespace_id]
+  end
+
   def namespaces_options(selected = :current_user, display_path: false, extra_group: nil)
     groups = current_user.owned_groups + current_user.masters_groups
 

app/views/projects/new.html.haml

@@ -22,7 +22,7 @@
                 - if current_user.can_select_namespace?
                   .input-group-addon
                     = root_url
-                  = f.select :namespace_id, namespaces_options(params[:namespace_id] || :current_user, display_path: true), {}, {class: 'select2 js-select-namespace', tabindex: 1}
+                  = f.select :namespace_id, namespaces_options(namespace_id_from(params) || :current_user, display_path: true), {}, {class: 'select2 js-select-namespace', tabindex: 1}
 
                 - else
                   .input-group-addon.static-namespace

spec/features/projects/new_project_spec.rb

@@ -19,6 +19,51 @@ feature "New project", feature: true do
     end
   end
 
+  context "Namespace selector" do
+    context "with user namespace" do
+      before do
+        visit new_project_path
+      end
+
+      it "selects the user namespace" do
+        namespace = find("#project_namespace_id")
+
+        expect(namespace.text).to eq user.username
+      end
+    end
+
+    context "with group namespace" do
+      let(:group) { create(:group, :private, owner: user) }
+
+      before do
+        group.add_owner(user)
+        visit new_project_path(namespace_id: group.id)
+      end
+
+      it "selects the group namespace" do
+        namespace = find("#project_namespace_id option[selected]")
+
+        expect(namespace.text).to eq group.name
+      end
+
+      context "on validation error" do
+        before do
+          fill_in('project_path', with: 'private-group-project')
+          choose('Internal')
+          click_button('Create project')
+
+          expect(page).to have_css '.project-edit-errors .alert.alert-danger'
+        end
+
+        it "selects the group namespace" do
+          namespace = find("#project_namespace_id option[selected]")
+
+          expect(namespace.text).to eq group.name
+        end
+      end
+    end
+  end
+
   context 'Import project options' do
     before do
       visit new_project_path