Support adding and removing labels w/ push opts

MergeRequests::PushOptionsHandlerService has been updated to allow
adding and removing labels to a merge request using git push options.

To create a new merge request and add 2 labels to it:

      git push -u origin -o merge_request.create \
        -o merge_request.label="My label 1" \
        -o merge_request.label="My label 2"

To update an existing merge request and remove a label while
adding a different label:

      git push -u origin -o merge_request.label="My added label" \
        -o merge_request.unlabel="My removed label"

Issue https://gitlab.com/gitlab-org/gitlab-ce/issues/64320

1 files changed, 145 insertions, 0 deletions

diff --git a/spec/services/merge_requests/push_options_handler_service_spec.rb b/spec/services/merge_requests/push_options_handler_service_spec.rb
index a27fea0c90f..ff4cdd3e7e2 100644
--- a/spec/services/merge_requests/push_options_handler_service_spec.rb
+++ b/spec/services/merge_requests/push_options_handler_service_spec.rb
@@ -13,6 +13,9 @@ describe MergeRequests::PushOptionsHandlerService do
   let(:target_branch) { 'feature' }
   let(:title) { 'my title' }
   let(:description) { 'my description' }
+  let(:label1) { 'mylabel1' }
+  let(:label2) { 'mylabel2' }
+  let(:label3) { 'mylabel3' }
   let(:new_branch_changes) { "#{Gitlab::Git::BLANK_SHA} 570e7b2abdd848b95f2f578043fc23bd6f6fd24d refs/heads/#{source_branch}" }
   let(:existing_branch_changes) { "d14d6c0abdd253381df51a723d58691b2ee1ab08 570e7b2abdd848b95f2f578043fc23bd6f6fd24d refs/heads/#{source_branch}" }
   let(:deleted_branch_changes) { "d14d6c0abdd253381df51a723d58691b2ee1ab08 #{Gitlab::Git::BLANK_SHA} refs/heads/#{source_branch}" }
@@ -122,6 +125,16 @@ describe MergeRequests::PushOptionsHandlerService do
     end
   end
 
+  shared_examples_for 'a service that can change labels of a merge request' do |count|
+    subject(:last_mr) { MergeRequest.last }
+
+    it 'changes label count' do
+      service.execute
+
+      expect(last_mr.label_ids.count).to eq(count)
+    end
+  end
+
   shared_examples_for 'a service that does not create a merge request' do
     it do
       expect { service.execute }.not_to change { MergeRequest.count }
@@ -504,6 +517,138 @@ describe MergeRequests::PushOptionsHandlerService do
     end
   end
 
+  describe '`label` push option' do
+    let(:push_options) { { label: { label1 => 1, label2 => 1 } } }
+
+    context 'with a new branch' do
+      let(:changes) { new_branch_changes }
+
+      it_behaves_like 'a service that does not create a merge request'
+
+      it 'adds an error to the service' do
+        error = "A merge_request.create push option is required to create a merge request for branch #{source_branch}"
+
+        service.execute
+
+        expect(service.errors).to include(error)
+      end
+
+      context 'when coupled with the `create` push option' do
+        let(:push_options) { { create: true, label: { label1 => 1, label2 => 1 } } }
+
+        it_behaves_like 'a service that can create a merge request'
+        it_behaves_like 'a service that can change labels of a merge request', 2
+      end
+    end
+
+    context 'with an existing branch but no open MR' do
+      let(:changes) { existing_branch_changes }
+
+      it_behaves_like 'a service that does not create a merge request'
+
+      it 'adds an error to the service' do
+        error = "A merge_request.create push option is required to create a merge request for branch #{source_branch}"
+
+        service.execute
+
+        expect(service.errors).to include(error)
+      end
+
+      context 'when coupled with the `create` push option' do
+        let(:push_options) { { create: true, label: { label1 => 1, label2 => 1 } } }
+
+        it_behaves_like 'a service that can create a merge request'
+        it_behaves_like 'a service that can change labels of a merge request', 2
+      end
+    end
+
+    context 'with an existing branch that has a merge request open' do
+      let(:changes) { existing_branch_changes }
+      let!(:merge_request) { create(:merge_request, source_project: project, source_branch: source_branch)}
+
+      it_behaves_like 'a service that does not create a merge request'
+      it_behaves_like 'a service that can change labels of a merge request', 2
+    end
+
+    context 'with a deleted branch' do
+      let(:changes) { deleted_branch_changes }
+
+      it_behaves_like 'a service that does nothing'
+    end
+
+    context 'with the project default branch' do
+      let(:changes) { default_branch_changes }
+
+      it_behaves_like 'a service that does nothing'
+    end
+  end
+
+  describe '`unlabel` push option' do
+    let(:push_options) { { label: { label1 => 1, label2 => 1 }, unlabel: { label1 => 1, label3 => 1 } } }
+
+    context 'with a new branch' do
+      let(:changes) { new_branch_changes }
+
+      it_behaves_like 'a service that does not create a merge request'
+
+      it 'adds an error to the service' do
+        error = "A merge_request.create push option is required to create a merge request for branch #{source_branch}"
+
+        service.execute
+
+        expect(service.errors).to include(error)
+      end
+
+      context 'when coupled with the `create` push option' do
+        let(:push_options) { { create: true, label: { label1 => 1, label2 => 1 }, unlabel: { label1 => 1, label3 => 1 } } }
+
+        it_behaves_like 'a service that can create a merge request'
+        it_behaves_like 'a service that can change labels of a merge request', 1
+      end
+    end
+
+    context 'with an existing branch but no open MR' do
+      let(:changes) { existing_branch_changes }
+
+      it_behaves_like 'a service that does not create a merge request'
+
+      it 'adds an error to the service' do
+        error = "A merge_request.create push option is required to create a merge request for branch #{source_branch}"
+
+        service.execute
+
+        expect(service.errors).to include(error)
+      end
+
+      context 'when coupled with the `create` push option' do
+        let(:push_options) { { create: true, label: { label1 => 1, label2 => 1 }, unlabel: { label1 => 1, label3 => 1 } } }
+
+        it_behaves_like 'a service that can create a merge request'
+        it_behaves_like 'a service that can change labels of a merge request', 1
+      end
+    end
+
+    context 'with an existing branch that has a merge request open' do
+      let(:changes) { existing_branch_changes }
+      let!(:merge_request) { create(:merge_request, source_project: project, source_branch: source_branch)}
+
+      it_behaves_like 'a service that does not create a merge request'
+      it_behaves_like 'a service that can change labels of a merge request', 1
+    end
+
+    context 'with a deleted branch' do
+      let(:changes) { deleted_branch_changes }
+
+      it_behaves_like 'a service that does nothing'
+    end
+
+    context 'with the project default branch' do
+      let(:changes) { default_branch_changes }
+
+      it_behaves_like 'a service that does nothing'
+    end
+  end
+
   describe 'multiple pushed branches' do
     let(:push_options) { { create: true } }
     let(:changes) do