Make commit status created for any pipelines by default

Resolves https://gitlab.com/gitlab-org/gitlab-ee/issues/14064.

On commit status creation, the controller tries to find pipeline that
matches the specified parameters. If 'ref' not is given as parameters,
'ref' will be assigned to branch name that contains 'sha' and pipeline
for 'ref' will be searched. If there is an existing pipeline for 'ref',
commit status stage is created and appended at the end of the pipeline.
Otherwise, it will create a new pipeline for 'ref'.

The above behavior is not desirable when the only pipelines available
are not for branch. One example of other 'ref' is merge request ref.
For these pipelines, the expected value of 'ref' is supposed to be the
merge request ref name. For example, merge request with ID 42 will have
/refs/merge-requests/42/head as its ref name. Thus, if there are only
pipelines for merge requests, unless we pass 'ref' explicitly, it will
create a new pipeline for the branch that contains the 'sha' instead of
adding the created stage to the existing pipeline for merge requests.

This commit change the logic so commit status can be created on any
pipelines by default. The goal can be achieved by changing the logic
when existing pipeline is searched using the given parameters. First,
if 'pipeline_id' is specified, search for pipeline that has the same id
as 'pipeline_id'. When 'pipeline_id' is not given, but 'ref' is given,
search for pipeline that has the same 'ref' and 'sha' value. Note that
'sha' will always be given. Otherwise, search the latest pipeline that
has the same 'sha', which will only returns nil if there is no pipeline
created for that particular 'sha'.

app/models/ci/pipeline.rb

@@ -211,6 +211,8 @@ module Ci
     scope :for_sha, -> (sha) { where(sha: sha) }
     scope :for_source_sha, -> (source_sha) { where(source_sha: source_sha) }
     scope :for_sha_or_source_sha, -> (sha) { for_sha(sha).or(for_source_sha(sha)) }
+    scope :for_ref, -> (ref) { where(ref: ref) }
+    scope :for_id, -> (id) { where(id: id) }
     scope :created_after, -> (time) { where('ci_pipelines.created_at > ?', time) }
 
     scope :triggered_by_merge_request, -> (merge_request) do

changelogs/unreleased/14064-commit-status-on-any-pipelines.yml

+---
+title: Make commit status created for any pipelines
+merge_request: 17524
+author: Aufar Gilbran
+type: changed

lib/api/commit_statuses.rb

@@ -58,7 +58,6 @@ module API
       post ':id/statuses/:sha' do
         authorize! :create_commit_status, user_project
 
-        commit = @project.commit(params[:sha])
         not_found! 'Commit' unless commit
 
         # Since the CommitStatus is attached to Ci::Pipeline (in the future Pipeline)
@@ -68,14 +67,15 @@ module API
         # If we don't receive it, we will attach the CommitStatus to
         # the first found branch on that commit
 
+        pipeline = all_matching_pipelines.first
+
         ref = params[:ref]
+        ref ||= pipeline&.ref
         ref ||= @project.repository.branch_names_contains(commit.sha).first
         not_found! 'References for commit' unless ref
 
         name = params[:name] || params[:context] || 'default'
 
-        pipeline = @project.pipeline_for(ref, commit.sha, params[:pipeline_id])
-
         unless pipeline
           pipeline = @project.ci_pipelines.create!(
             source: :external,
@@ -126,6 +126,20 @@ module API
         end
       end
       # rubocop: enable CodeReuse/ActiveRecord
+      helpers do
+        def commit
+          strong_memoize(:commit) do
+            user_project.commit(params[:sha])
+          end
+        end
+
+        def all_matching_pipelines
+          pipelines = user_project.ci_pipelines.newest_first(sha: commit.sha)
+          pipelines = pipelines.for_ref(params[:ref]) if params[:ref]
+          pipelines = pipelines.for_id(params[:pipeline_id]) if params[:pipeline_id]
+          pipelines
+        end
+      end
     end
   end
 end

spec/requests/api/commit_statuses_spec.rb

@@ -125,25 +125,55 @@ describe API::CommitStatuses do
     let(:post_url) { "/projects/#{project.id}/statuses/#{sha}" }
 
     context 'developer user' do
-      %w[pending running success failed canceled].each do |status|
-        context "for #{status}" do
-          context 'uses only required parameters' do
-            it 'creates commit status' do
-              post api(post_url, developer), params: { state: status }
+      context 'uses only required parameters' do
+        %w[pending running success failed canceled].each do |status|
+          context "for #{status}" do
+            context 'when pipeline for sha does not exists' do
+              it 'creates commit status' do
+                post api(post_url, developer), params: { state: status }
+
+                expect(response).to have_gitlab_http_status(201)
+                expect(json_response['sha']).to eq(commit.id)
+                expect(json_response['status']).to eq(status)
+                expect(json_response['name']).to eq('default')
+                expect(json_response['ref']).not_to be_empty
+                expect(json_response['target_url']).to be_nil
+                expect(json_response['description']).to be_nil
+
+                if status == 'failed'
+                  expect(CommitStatus.find(json_response['id'])).to be_api_failure
+                end
+              end
+            end
+          end
+        end
+
+        context 'when pipeline already exists for the specified sha' do
+          let!(:pipeline) { create(:ci_pipeline, project: project, sha: sha, ref: 'ref') }
+          let(:params) { { state: 'pending' } }
+
+          shared_examples_for 'creates a commit status for the existing pipeline' do
+            it do
+              expect do
+                post api(post_url, developer), params: params
+              end.not_to change { Ci::Pipeline.count }
+
+              job = pipeline.statuses.find_by_name(json_response['name'])
 
               expect(response).to have_gitlab_http_status(201)
-              expect(json_response['sha']).to eq(commit.id)
-              expect(json_response['status']).to eq(status)
-              expect(json_response['name']).to eq('default')
-              expect(json_response['ref']).not_to be_empty
-              expect(json_response['target_url']).to be_nil
-              expect(json_response['description']).to be_nil
-
-              if status == 'failed'
-                expect(CommitStatus.find(json_response['id'])).to be_api_failure
-              end
+              expect(job.status).to eq('pending')
             end
           end
+
+          it_behaves_like 'creates a commit status for the existing pipeline'
+
+          context 'with pipeline for merge request' do
+            let!(:merge_request) { create(:merge_request, :with_detached_merge_request_pipeline, source_project: project) }
+            let!(:pipeline) { merge_request.all_pipelines.last }
+            let(:sha) { pipeline.sha }
+
+            it_behaves_like 'creates a commit status for the existing pipeline'
+          end
         end
       end