Merge branch 'fix/builds-api-builds-for-commit-search' into 'master'

Find all builds for commit if there are multiple pipelines for it

## What does this MR do?

This MR fixes a builds API. When multiple pipelines were triggered for a commit, then API returned builds only from the last pipeline.

## What are the relevant issue numbers?

Closes #18912  
Closes #19243 

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] API support added
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !4849

4 files changed, 58 insertions, 15 deletions

diff --git a/CHANGELOG b/CHANGELOG
index dcec98469cb..f25b424d115 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,6 +1,7 @@
 Please view this file on the master branch, on stable branches it's out of date.
 
 v 8.10.0 (unreleased)
+  - Fix commit builds API, return all builds for all pipelines for given commit. !4849
   - Replace Haml with Hamlit to make view rendering faster. !3666
   - Wrap code blocks on Activies and Todos page. !4783 (winniehell)
   - Display last commit of deleted branch in push events !4699 (winniehell)
diff --git a/doc/api/builds.md b/doc/api/builds.md
index de998944352..2adea11247e 100644
--- a/doc/api/builds.md
+++ b/doc/api/builds.md
@@ -107,6 +107,11 @@ Example of response
 
 Get a list of builds for specific commit in a project.
 
+This endpoint will return all builds, from all pipelines for a given commit.
+If the commit SHA is not found, it will respond with 404, otherwise it will
+return an array of builds (an empty array if there are no builds for this
+particular commit).
+
 ```
 GET /projects/:id/repository/commits/:sha/builds
 ```
diff --git a/lib/api/builds.rb b/lib/api/builds.rb
index 979328efe0e..086d8511e8f 100644
--- a/lib/api/builds.rb
+++ b/lib/api/builds.rb
@@ -33,10 +33,10 @@ module API
       get ':id/repository/commits/:sha/builds' do
         authorize_read_builds!
 
-        commit = user_project.pipelines.find_by_sha(params[:sha])
-        return not_found! unless commit
+        return not_found! unless user_project.commit(params[:sha])
 
-        builds = commit.builds.order('id DESC')
+        pipelines = user_project.pipelines.where(sha: params[:sha])
+        builds = user_project.builds.where(pipeline: pipelines).order('id DESC')
         builds = filter_builds(builds, params[:scope])
 
         present paginate(builds), with: Entities::Build,
diff --git a/spec/requests/api/builds_spec.rb b/spec/requests/api/builds_spec.rb
index 2ab9d640269..f5b39c3d698 100644
--- a/spec/requests/api/builds_spec.rb
+++ b/spec/requests/api/builds_spec.rb
@@ -63,23 +63,60 @@ describe API::API, api: true  do
   end
 
   describe 'GET /projects/:id/repository/commits/:sha/builds' do
-    before do
-      project.ensure_pipeline(pipeline.sha, 'master')
-      get api("/projects/#{project.id}/repository/commits/#{pipeline.sha}/builds", api_user)
-    end
+    context 'when commit does not exist in repository' do
+      before do
+        get api("/projects/#{project.id}/repository/commits/1a271fd1/builds", api_user)
+      end
 
-    context 'authorized user' do
-      it 'should return project builds for specific commit' do
-        expect(response).to have_http_status(200)
-        expect(json_response).to be_an Array
+      it 'responds with 404' do
+        expect(response).to have_http_status(404)
       end
     end
 
-    context 'unauthorized user' do
-      let(:api_user) { nil }
+    context 'when commit exists in repository' do
+      context 'when user is authorized' do
+        context 'when pipeline has builds' do
+          before do
+            create(:ci_pipeline, project: project, sha: project.commit.id)
+            create(:ci_build, pipeline: pipeline)
+            create(:ci_build)
+
+            get api("/projects/#{project.id}/repository/commits/#{project.commit.id}/builds", api_user)
+          end
+
+          it 'should return project builds for specific commit' do
+            expect(response).to have_http_status(200)
+            expect(json_response).to be_an Array
+            expect(json_response.size).to eq 2
+          end
+        end
 
-      it 'should not return project builds' do
-        expect(response).to have_http_status(401)
+        context 'when pipeline has no builds' do
+          before do
+            branch_head = project.commit('feature').id
+            get api("/projects/#{project.id}/repository/commits/#{branch_head}/builds", api_user)
+          end
+
+          it 'returns an empty array' do
+            expect(response).to have_http_status(200)
+            expect(json_response).to be_an Array
+            expect(json_response).to be_empty
+          end
+        end
+      end
+
+      context 'when user is not authorized' do
+        before do
+          create(:ci_pipeline, project: project, sha: project.commit.id)
+          create(:ci_build, pipeline: pipeline)
+
+          get api("/projects/#{project.id}/repository/commits/#{project.commit.id}/builds", nil)
+        end
+
+        it 'should not return project builds' do
+          expect(response).to have_http_status(401)
+          expect(json_response.except('message')).to be_empty
+        end
       end
     end
   end