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.

4 files changed, 66 insertions, 0 deletions

diff --git a/spec/lib/gitlab/ci/build/policy/refs_spec.rb b/spec/lib/gitlab/ci/build/policy/refs_spec.rb
index 43c5d3ec980..8fc1e0a4e88 100644
--- a/spec/lib/gitlab/ci/build/policy/refs_spec.rb
+++ b/spec/lib/gitlab/ci/build/policy/refs_spec.rb
@@ -84,6 +84,20 @@ describe Gitlab::Ci::Build::Policy::Refs do
             .not_to be_satisfied_by(pipeline)
         end
       end
+
+      context 'when source is external_pull_request_event' do
+        let(:pipeline) { build_stubbed(:ci_pipeline, source: :external_pull_request_event) }
+
+        it 'is satisfied with only: external_pull_request' do
+          expect(described_class.new(%w[external_pull_requests]))
+            .to be_satisfied_by(pipeline)
+        end
+
+        it 'is not satisfied with only: external_pull_request_event' do
+          expect(described_class.new(%w[external_pull_request_events]))
+            .not_to be_satisfied_by(pipeline)
+        end
+      end
     end
 
     context 'when matching a ref by a regular expression' do
diff --git a/spec/lib/gitlab/ci/pipeline/chain/build_spec.rb b/spec/lib/gitlab/ci/pipeline/chain/build_spec.rb
index bf9ff922c05..ba4f841cf43 100644
--- a/spec/lib/gitlab/ci/pipeline/chain/build_spec.rb
+++ b/spec/lib/gitlab/ci/pipeline/chain/build_spec.rb
@@ -128,4 +128,38 @@ describe Gitlab::Ci::Pipeline::Chain::Build do
       expect(pipeline.target_sha).to eq(merge_request.target_branch_sha)
     end
   end
+
+  context 'when pipeline is running for an external pull request' do
+    let(:command) do
+      Gitlab::Ci::Pipeline::Chain::Command.new(
+        source: :external_pull_request_event,
+        origin_ref: 'feature',
+        checkout_sha: project.commit.id,
+        after_sha: nil,
+        before_sha: nil,
+        source_sha: external_pull_request.source_sha,
+        target_sha: external_pull_request.target_sha,
+        trigger_request: nil,
+        schedule: nil,
+        external_pull_request: external_pull_request,
+        project: project,
+        current_user: user)
+    end
+
+    let(:external_pull_request) { build(:external_pull_request, project: project) }
+
+    before do
+      step.perform!
+    end
+
+    it 'correctly indicated that this is an external pull request pipeline' do
+      expect(pipeline).to be_external_pull_request_event
+      expect(pipeline.external_pull_request).to eq(external_pull_request)
+    end
+
+    it 'correctly sets source sha and target sha to pipeline' do
+      expect(pipeline.source_sha).to eq(external_pull_request.source_sha)
+      expect(pipeline.target_sha).to eq(external_pull_request.target_sha)
+    end
+  end
 end
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 47ba7eff8ed..a71619315d5 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -126,6 +126,8 @@ merge_requests:
 - blocks_as_blockee
 - blocking_merge_requests
 - blocked_merge_requests
+external_pull_requests:
+- project
 merge_request_diff:
 - merge_request
 - merge_request_diff_commits
@@ -155,6 +157,7 @@ ci_pipelines:
 - pipeline_schedule
 - merge_requests_as_head_pipeline
 - merge_request
+- external_pull_request
 - deployments
 - environments
 - chat_data
@@ -402,6 +405,7 @@ project:
 - merge_trains
 - designs
 - project_aliases
+- external_pull_requests
 award_emoji:
 - awardable
 - user
diff --git a/spec/lib/gitlab/import_export/safe_model_attributes.yml b/spec/lib/gitlab/import_export/safe_model_attributes.yml
index 516e62c4728..1fa216f34b5 100644
--- a/spec/lib/gitlab/import_export/safe_model_attributes.yml
+++ b/spec/lib/gitlab/import_export/safe_model_attributes.yml
@@ -270,6 +270,7 @@ Ci::Pipeline:
 - protected
 - iid
 - merge_request_id
+- external_pull_request_id
 Ci::Stage:
 - id
 - name
@@ -713,3 +714,16 @@ List:
 - updated_at
 - milestone_id
 - user_id
+ExternalPullRequest:
+- id
+- created_at
+- updated_at
+- project_id
+- pull_request_iid
+- status
+- source_branch
+- target_branch
+- source_repository
+- target_repository
+- source_sha
+- target_sha