Merge branch '23990-project-show-error-when-empty-repo' into 'master'

500 error on project show when user is not logged in and project is still empty

## What does this MR do?

Aims to fix the 500 error when the project is empty and the user is not logged in and tries to access project#show

## Screenshots (if relevant)
When the project is empty and the user is not logged in we default to the empty project partial instead of readme.

![Screen_Shot_2016-11-11_at_22.54.21](/uploads/3d87e65195376c85d3e515e6d5a9a850/Screen_Shot_2016-11-11_at_22.54.21.png)

## Does this MR meet the acceptance criteria?

- [x] [Changelog entry](https://docs.gitlab.com/ce/development/changelog.html) added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [merge request performance guides](http://docs.gitlab.com/ce/development/merge_request_performance_guidelines.html)
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if it does - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

## What are the relevant issue numbers?

Closes #23990

See merge request !7376

app/helpers/preferences_helper.rb

@@ -50,7 +50,7 @@ module PreferencesHelper
   end
 
   def default_project_view
-    return 'readme' unless current_user
+    return anonymous_project_view unless current_user
 
     user_view = current_user.project_view
 
@@ -66,4 +66,8 @@ module PreferencesHelper
       "customize_workflow"
     end
   end
+
+  def anonymous_project_view
+    @project.empty_repo? || !can?(current_user, :download_code, @project) ? 'activity' : 'readme'
+  end
 end

changelogs/unreleased/23990-project-show-error-when-empty-repo.yml

+---
+title: fixes 500 error on project show when user is not logged in and project is still empty
+merge_request: 7376
+author: 

spec/helpers/preferences_helper_spec.rb

@@ -85,4 +85,45 @@ describe PreferencesHelper do
         and_return(double('user', messages))
     end
   end
+
+  describe '#default_project_view' do
+    context 'user not signed in' do
+      before do
+        helper.instance_variable_set(:@project, project)
+        stub_user
+      end
+
+      context 'when repository is empty' do
+        let(:project) { create(:project_empty_repo, :public) }
+
+        it 'returns activity if user has repository access' do
+          allow(helper).to receive(:can?).with(nil, :download_code, project).and_return(true)
+
+          expect(helper.default_project_view).to eq('activity')
+        end
+
+        it 'returns activity if user does not have repository access' do
+          allow(helper).to receive(:can?).with(nil, :download_code, project).and_return(false)
+
+          expect(helper.default_project_view).to eq('activity')
+        end
+      end
+
+      context 'when repository is not empty' do
+        let(:project) { create(:project, :public) }
+
+        it 'returns readme if user has repository access' do
+          allow(helper).to receive(:can?).with(nil, :download_code, project).and_return(true)
+
+          expect(helper.default_project_view).to eq('readme')
+        end
+
+        it 'returns activity if user does not have repository access' do
+          allow(helper).to receive(:can?).with(nil, :download_code, project).and_return(false)
+
+          expect(helper.default_project_view).to eq('activity')
+        end
+      end
+    end
+  end
 end