Merge branch 'feature/group-level-labels' into 'master'

Add group level labels

## What does this MR do?

Add group level labels.

## Are there points in the code the reviewer needs to double check?

* `LabelsFinder`
* `Gitlab::Gfm::ReferenceRewriter`
* `Banzai::Filter::LabelReferenceFilter`

## Why was this MR needed?

We'll be adding more feature that allow you to do cross-project management of issues.

## Screenshots (if relevant)

* Group Labels
    ![Group Labels](/uploads/2244c06ad68eae4fb246fb4c81bf8060/2.png)

* Project Labels
    ![Project Labels](/uploads/c5839516d2282b51f7418d9dadbeceb4/1.png)

* Expanded references for group labels when moving issue to another project
    ![Expanded references for group labels when moving issue to another project](/uploads/0c9ab248a8420d4978d59349ae3d42e5/3.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [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
  - [ ] All builds are passing
- [ ] 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)
- [ ] Branch has no merge conflicts with `master` (if you do - 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?

#19997

See merge request !6425

6 files changed, 146 insertions, 0 deletions

diff --git a/spec/services/boards/lists/create_service_spec.rb b/spec/services/boards/lists/create_service_spec.rb
index e7806add916..a7e9efcf93f 100644
--- a/spec/services/boards/lists/create_service_spec.rb
+++ b/spec/services/boards/lists/create_service_spec.rb
@@ -9,6 +9,10 @@ describe Boards::Lists::CreateService, services: true do
 
     subject(:service) { described_class.new(project, user, label_id: label.id) }
 
+    before do
+      project.team << [user, :developer]
+    end
+
     context 'when board lists is empty' do
       it 'creates a new list at beginning of the list' do
         list = service.execute(board)
diff --git a/spec/services/boards/lists/generate_service_spec.rb b/spec/services/boards/lists/generate_service_spec.rb
index 8b2f5e81338..ed0337662af 100644
--- a/spec/services/boards/lists/generate_service_spec.rb
+++ b/spec/services/boards/lists/generate_service_spec.rb
@@ -8,6 +8,10 @@ describe Boards::Lists::GenerateService, services: true do
 
     subject(:service) { described_class.new(project, user) }
 
+    before do
+      project.team << [user, :developer]
+    end
+
     context 'when board lists is empty' do
       it 'creates the default lists' do
         expect { service.execute(board) }.to change(board.lists, :count).by(2)
diff --git a/spec/services/issues/create_service_spec.rb b/spec/services/issues/create_service_spec.rb
index 1050502fa19..5c0331ebe66 100644
--- a/spec/services/issues/create_service_spec.rb
+++ b/spec/services/issues/create_service_spec.rb
@@ -67,6 +67,27 @@ describe Issues::CreateService, services: true do
         expect(Todo.where(attributes).count).to eq 1
       end
 
+      context 'when label belongs to project group' do
+        let(:group) { create(:group) }
+        let(:group_labels) { create_pair(:group_label, group: group) }
+
+        let(:opts) do
+          {
+            title: 'Title',
+            description: 'Description',
+            label_ids: group_labels.map(&:id)
+          }
+        end
+
+        before do
+          project.update(group: group)
+        end
+
+        it 'assigns group labels' do
+          expect(issue.labels).to match_array group_labels
+        end
+      end
+
       context 'when label belongs to different project' do
         let(:label) { create(:label) }
 
diff --git a/spec/services/labels/find_or_create_service_spec.rb b/spec/services/labels/find_or_create_service_spec.rb
new file mode 100644
index 00000000000..cbfc63de811
--- /dev/null
+++ b/spec/services/labels/find_or_create_service_spec.rb
@@ -0,0 +1,51 @@
+require 'spec_helper'
+
+describe Labels::FindOrCreateService, services: true do
+  describe '#execute' do
+    let(:user)    { create(:user) }
+    let(:group)   { create(:group) }
+    let(:project) { create(:project, namespace: group) }
+
+    let(:params) do
+      {
+        title: 'Security',
+        description: 'Security related stuff.',
+        color: '#FF0000'
+      }
+    end
+
+    subject(:service) { described_class.new(user, project, params) }
+
+    before do
+      project.team << [user, :developer]
+    end
+
+    context 'when label does not exist at group level' do
+      it 'creates a new label at project level' do
+        expect { service.execute }.to change(project.labels, :count).by(1)
+      end
+    end
+
+    context 'when label exists at group level' do
+      it 'returns the group label' do
+        group_label = create(:group_label, group: group, title: 'Security')
+
+        expect(service.execute).to eq group_label
+      end
+    end
+
+    context 'when label does not exist at group level' do
+      it 'creates a new label at project leve' do
+        expect { service.execute }.to change(project.labels, :count).by(1)
+      end
+    end
+
+    context 'when label exists at project level' do
+      it 'returns the project label' do
+        project_label = create(:label, project: project, title: 'Security')
+
+        expect(service.execute).to eq project_label
+      end
+    end
+  end
+end
diff --git a/spec/services/labels/transfer_service_spec.rb b/spec/services/labels/transfer_service_spec.rb
new file mode 100644
index 00000000000..ddf3527dc0f
--- /dev/null
+++ b/spec/services/labels/transfer_service_spec.rb
@@ -0,0 +1,56 @@
+require 'spec_helper'
+
+describe Labels::TransferService, services: true do
+  describe '#execute' do
+    let(:user)    { create(:user) }
+    let(:group_1) { create(:group) }
+    let(:group_2) { create(:group) }
+    let(:group_3) { create(:group) }
+    let(:project_1) { create(:project, namespace: group_2) }
+    let(:project_2) { create(:project, namespace: group_3) }
+
+    let(:group_label_1) { create(:group_label, group: group_1, name: 'Group Label 1') }
+    let(:group_label_2) { create(:group_label, group: group_1, name: 'Group Label 2') }
+    let(:group_label_3) { create(:group_label, group: group_1, name: 'Group Label 3') }
+    let(:group_label_4) { create(:group_label, group: group_2, name: 'Group Label 4') }
+    let(:group_label_5) { create(:group_label, group: group_3, name: 'Group Label 5') }
+    let(:project_label_1) { create(:label, project: project_1, name: 'Project Label 1') }
+
+    subject(:service) { described_class.new(user, group_1, project_1) }
+
+    before do
+      create(:labeled_issue, project: project_1, labels: [group_label_1])
+      create(:labeled_issue, project: project_1, labels: [group_label_4])
+      create(:labeled_issue, project: project_1, labels: [project_label_1])
+      create(:labeled_issue, project: project_2, labels: [group_label_5])
+      create(:labeled_merge_request, source_project: project_1, labels: [group_label_1, group_label_2])
+      create(:labeled_merge_request, source_project: project_2, labels: [group_label_5])
+    end
+
+    it 'recreates the missing group labels at project level' do
+      expect { service.execute }.to change(project_1.labels, :count).by(2)
+    end
+
+    it 'recreates label priorities related to the missing group labels' do
+      create(:label_priority, project: project_1, label: group_label_1, priority: 1)
+
+      service.execute
+
+      new_project_label = project_1.labels.find_by(title: group_label_1.title)
+      expect(new_project_label.id).not_to eq group_label_1.id
+      expect(new_project_label.priorities).not_to be_empty
+    end
+
+    it 'does not recreate missing group labels that are not applied to issues or merge requests' do
+      service.execute
+
+      expect(project_1.labels.where(title: group_label_3.title)).to be_empty
+    end
+
+    it 'does not recreate missing group labels that already exist in the project group' do
+      service.execute
+
+      expect(project_1.labels.where(title: group_label_4.title)).to be_empty
+    end
+  end
+end
diff --git a/spec/services/projects/transfer_service_spec.rb b/spec/services/projects/transfer_service_spec.rb
index 57c71544dff..1540b90163a 100644
--- a/spec/services/projects/transfer_service_spec.rb
+++ b/spec/services/projects/transfer_service_spec.rb
@@ -71,4 +71,14 @@ describe Projects::TransferService, services: true do
       it { expect(private_project.visibility_level).to eq(Gitlab::VisibilityLevel::PRIVATE) }
     end
   end
+
+  context 'missing group labels applied to issues or merge requests' do
+    it 'delegates tranfer to Labels::TransferService' do
+      group.add_owner(user)
+
+      expect_any_instance_of(Labels::TransferService).to receive(:execute).once.and_call_original
+
+      transfer_project(project, user, group)
+    end
+  end
 end