CE port for pipelines for external pull requests

Detect if pipeline runs for a GitHub pull request

When using a mirror for CI/CD only we register a pull_request
webhook. When a pull_request webhook is received, if the
source branch SHA matches the actual head of the branch in the
repository we create immediately a new pipeline for the
external pull request. Otherwise we store the
pull request info for when the push webhook is received.

When using "only/except: external_pull_requests" we can detect
if the pipeline has a open pull request on GitHub and create or
not the job based on that.

1 files changed, 220 insertions, 0 deletions

diff --git a/spec/models/external_pull_request_spec.rb b/spec/models/external_pull_request_spec.rb
new file mode 100644
index 00000000000..e85d5b2f6c7
--- /dev/null
+++ b/spec/models/external_pull_request_spec.rb
@@ -0,0 +1,220 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe ExternalPullRequest do
+  let(:project) { create(:project) }
+  let(:source_branch) { 'the-branch' }
+  let(:status) { :open }
+
+  it { is_expected.to belong_to(:project) }
+
+  shared_examples 'has errors on' do |attribute|
+    it "has errors for #{attribute}" do
+      expect(subject).not_to be_valid
+      expect(subject.errors[attribute]).not_to be_empty
+    end
+  end
+
+  describe 'validations' do
+    context 'when source branch not present' do
+      subject { build(:external_pull_request, source_branch: nil) }
+
+      it_behaves_like 'has errors on', :source_branch
+    end
+
+    context 'when status not present' do
+      subject { build(:external_pull_request, status: nil) }
+
+      it_behaves_like 'has errors on', :status
+    end
+
+    context 'when pull request is from a fork' do
+      subject { build(:external_pull_request, source_repository: 'the-fork', target_repository: 'the-target') }
+
+      it_behaves_like 'has errors on', :base
+    end
+  end
+
+  describe 'create_or_update_from_params' do
+    subject { described_class.create_or_update_from_params(params) }
+
+    context 'when pull request does not exist' do
+      context 'when params are correct' do
+        let(:params) do
+          {
+            project_id: project.id,
+            pull_request_iid: 123,
+            source_branch: 'feature',
+            target_branch: 'master',
+            source_repository: 'the-repository',
+            target_repository: 'the-repository',
+            source_sha: '97de212e80737a608d939f648d959671fb0a0142',
+            target_sha: 'a09386439ca39abe575675ffd4b89ae824fec22f',
+            status: :open
+          }
+        end
+
+        it 'saves the model successfully and returns it' do
+          expect(subject).to be_persisted
+          expect(subject).to be_valid
+        end
+
+        it 'yields the model' do
+          yielded_value = nil
+
+          result = described_class.create_or_update_from_params(params) do |pull_request|
+            yielded_value = pull_request
+          end
+
+          expect(result).to eq(yielded_value)
+        end
+      end
+
+      context 'when params are not correct' do
+        let(:params) do
+          {
+            pull_request_iid: 123,
+            source_branch: 'feature',
+            target_branch: 'master',
+            source_repository: 'the-repository',
+            target_repository: 'the-repository',
+            source_sha: nil,
+            target_sha: nil,
+            status: :open
+          }
+        end
+
+        it 'returns an invalid model' do
+          expect(subject).not_to be_persisted
+          expect(subject).not_to be_valid
+        end
+      end
+    end
+
+    context 'when pull request exists' do
+      let!(:pull_request) do
+        create(:external_pull_request,
+          project: project,
+          source_sha: '97de212e80737a608d939f648d959671fb0a0142')
+      end
+
+      context 'when params are correct' do
+        let(:params) do
+          {
+            pull_request_iid: pull_request.pull_request_iid,
+            source_branch: pull_request.source_branch,
+            target_branch: pull_request.target_branch,
+            source_repository: 'the-repository',
+            target_repository: 'the-repository',
+            source_sha: 'ce84140e8b878ce6e7c4d298c7202ff38170e3ac',
+            target_sha: pull_request.target_sha,
+            status: :open
+          }
+        end
+
+        it 'updates the model successfully and returns it' do
+          expect(subject).to be_valid
+          expect(subject.source_sha).to eq(params[:source_sha])
+          expect(pull_request.reload.source_sha).to eq(params[:source_sha])
+        end
+      end
+
+      context 'when params are not correct' do
+        let(:params) do
+          {
+            pull_request_iid: pull_request.pull_request_iid,
+            source_branch: pull_request.source_branch,
+            target_branch: pull_request.target_branch,
+            source_repository: 'the-repository',
+            target_repository: 'the-repository',
+            source_sha: nil,
+            target_sha: nil,
+            status: :open
+          }
+        end
+
+        it 'returns an invalid model' do
+          expect(subject).not_to be_valid
+          expect(pull_request.reload.source_sha).not_to be_nil
+          expect(pull_request.target_sha).not_to be_nil
+        end
+      end
+    end
+  end
+
+  describe '#open?' do
+    it 'returns true if status is open' do
+      pull_request = create(:external_pull_request, status: :open)
+
+      expect(pull_request).to be_open
+    end
+
+    it 'returns false if status is not open' do
+      pull_request = create(:external_pull_request, status: :closed)
+
+      expect(pull_request).not_to be_open
+    end
+  end
+
+  describe '#closed?' do
+    it 'returns true if status is closed' do
+      pull_request = build(:external_pull_request, status: :closed)
+
+      expect(pull_request).to be_closed
+    end
+
+    it 'returns false if status is not closed' do
+      pull_request = build(:external_pull_request, status: :open)
+
+      expect(pull_request).not_to be_closed
+    end
+  end
+
+  describe '#actual_branch_head?' do
+    let(:project) { create(:project, :repository) }
+    let(:branch) { project.repository.branches.first }
+    let(:source_branch) { branch.name }
+
+    let(:pull_request) do
+      create(:external_pull_request,
+        project: project,
+        source_branch: source_branch,
+        source_sha: source_sha)
+    end
+
+    context 'when source sha matches the head of the branch' do
+      let(:source_sha) { branch.target }
+
+      it 'returns true' do
+        expect(pull_request).to be_actual_branch_head
+      end
+    end
+
+    context 'when source sha does not match the head of the branch' do
+      let(:source_sha) { project.repository.commit('HEAD').sha }
+
+      it 'returns true' do
+        expect(pull_request).not_to be_actual_branch_head
+      end
+    end
+  end
+
+  describe '#from_fork?' do
+    it 'returns true if source_repository differs from target_repository' do
+      pull_request = build(:external_pull_request,
+        source_repository: 'repository-1',
+        target_repository: 'repository-2')
+
+      expect(pull_request).to be_from_fork
+    end
+
+    it 'returns false if source_repository is the same as target_repository' do
+      pull_request = build(:external_pull_request,
+        source_repository: 'repository-1',
+        target_repository: 'repository-1')
+
+      expect(pull_request).not_to be_from_fork
+    end
+  end
+end