Merge branch 'sh-fix-failing-gpg-signature-ce' into 'master'

Make CreateGpgSignatureWorker backwards compatible with original method signature (CE port)

See merge request gitlab-org/gitlab-ce!20998

app/workers/create_gpg_signature_worker.rb

@@ -4,6 +4,10 @@ class CreateGpgSignatureWorker
   include ApplicationWorker
 
   def perform(commit_shas, project_id)
+    # Older versions of GitPushService may push a single commit ID on the stack.
+    # We need this to be backwards compatible.
+    commit_shas = Array(commit_shas)
+
     return if commit_shas.empty?
 
     project = Project.find_by(id: project_id)

spec/workers/create_gpg_signature_worker_spec.rb

@@ -4,10 +4,9 @@ describe CreateGpgSignatureWorker do
   let(:project) { create(:project, :repository) }
   let(:commits) { project.repository.commits('HEAD', limit: 3).commits }
   let(:commit_shas) { commits.map(&:id) }
-
-  context 'when GpgKey is found' do
   let(:gpg_commit) { instance_double(Gitlab::Gpg::Commit) }
 
+  context 'when GpgKey is found' do
     before do
       allow(Project).to receive(:find_by).with(id: project.id).and_return(project)
       allow(project).to receive(:commits_by).with(oids: commit_shas).and_return(commits)
@@ -36,6 +35,16 @@ describe CreateGpgSignatureWorker do
     end
   end
 
+  context 'handles when a string is passed in for the commit SHA' do
+    it 'creates a signature once' do
+      allow(Gitlab::Gpg::Commit).to receive(:new).with(commits.first).and_return(gpg_commit)
+
+      expect(gpg_commit).to receive(:signature).once
+
+      described_class.new.perform(commit_shas.first, project.id)
+    end
+  end
+
   context 'when Commit is not found' do
     let(:nonexisting_commit_sha) { '0beec7b5ea3f0fdbc95d0dd47f3c5bc275da8a34' }