From 4ae411ff40352ec21bd10f859b7f3f9f85a7aee6 Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Fri, 17 Mar 2017 19:14:27 -0300
Subject: [PATCH 1/6] Preloads head pipeline for each merge request

---
 app/controllers/concerns/issuable_collections.rb     |  2 +-
 app/models/merge_request.rb                          |  8 ++------
 app/services/ci/create_pipeline_service.rb           |  8 +++++++-
 changelogs/unreleased/issue_27168_2.yml              |  4 ++++
 ...7205316_add_head_pipeline_id_to_merge_requests.rb |  7 +++++++
 db/schema.rb                                         |  2 ++
 .../gitlab/import_export/safe_model_attributes.yml   |  1 +
 spec/services/ci/create_pipeline_service_spec.rb     | 12 ++++++++++++
 8 files changed, 36 insertions(+), 8 deletions(-)
 create mode 100644 changelogs/unreleased/issue_27168_2.yml
 create mode 100644 db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb

diff --git a/app/controllers/concerns/issuable_collections.rb b/app/controllers/concerns/issuable_collections.rb
index 6df2c068745..650ec1e326a 100644
--- a/app/controllers/concerns/issuable_collections.rb
+++ b/app/controllers/concerns/issuable_collections.rb
@@ -47,7 +47,7 @@ module IssuableCollections
   end
 
   def merge_requests_collection
-    merge_requests_finder.execute.preload(:source_project, :target_project, :author, :assignee, :labels, :milestone, :merge_request_diff, target_project: :namespace)
+    merge_requests_finder.execute.preload(:source_project, :target_project, :author, :assignee, :labels, :milestone, :merge_request_diff, :head_pipeline, target_project: :namespace)
   end
 
   def issues_finder
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index 35231bab12e..3a2cff6ac21 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -13,6 +13,8 @@ class MergeRequest < ActiveRecord::Base
   has_one :merge_request_diff,
     -> { order('merge_request_diffs.id DESC') }
 
+  belongs_to :head_pipeline, foreign_key: "head_pipeline_id", class_name: "Ci::Pipeline"
+
   has_many :events, as: :target, dependent: :destroy
 
   has_many :merge_requests_closing_issues, class_name: 'MergeRequestsClosingIssues', dependent: :delete_all
@@ -829,12 +831,6 @@ class MergeRequest < ActiveRecord::Base
     diverged_commits_count > 0
   end
 
-  def head_pipeline
-    return unless diff_head_sha && source_project
-
-    @head_pipeline ||= source_project.pipeline_for(source_branch, diff_head_sha)
-  end
-
   def all_pipelines
     return Ci::Pipeline.none unless source_project
 
diff --git a/app/services/ci/create_pipeline_service.rb b/app/services/ci/create_pipeline_service.rb
index ccdda08d885..26b744ae3c4 100644
--- a/app/services/ci/create_pipeline_service.rb
+++ b/app/services/ci/create_pipeline_service.rb
@@ -47,7 +47,7 @@ module Ci
       end
 
       Ci::Pipeline.transaction do
-        pipeline.save
+        update_merge_requests_head_pipeline if pipeline.save
 
         Ci::CreatePipelineBuildsService
           .new(project, current_user)
@@ -118,6 +118,12 @@ module Ci
       origin_sha && origin_sha != Gitlab::Git::BLANK_SHA
     end
 
+    def update_merge_requests_head_pipeline
+      merge_requests = MergeRequest.where(source_branch: @pipeline.ref, source_project: @pipeline.project)
+
+      merge_requests.update_all(head_pipeline_id: @pipeline.id) if merge_requests.any?
+    end
+
     def error(message, save: false)
       pipeline.errors.add(:base, message)
       pipeline.drop if save
diff --git a/changelogs/unreleased/issue_27168_2.yml b/changelogs/unreleased/issue_27168_2.yml
new file mode 100644
index 00000000000..c91a95323d5
--- /dev/null
+++ b/changelogs/unreleased/issue_27168_2.yml
@@ -0,0 +1,4 @@
+---
+title: Preloads head pipeline for each merge request
+merge_request:
+author:
diff --git a/db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb b/db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb
new file mode 100644
index 00000000000..8fc6e380a77
--- /dev/null
+++ b/db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb
@@ -0,0 +1,7 @@
+class AddHeadPipelineIdToMergeRequests < ActiveRecord::Migration
+  DOWNTIME = false
+
+  def change
+    add_column :merge_requests, :head_pipeline_id, :integer
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 722e776c27d..d5b1d3bb0d8 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -123,6 +123,7 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.integer "cached_markdown_version"
     t.boolean "clientside_sentry_enabled", default: false, null: false
     t.string "clientside_sentry_dsn"
+    t.string "default_artifacts_expire_in", default: "0", null: false
   end
 
   create_table "audit_events", force: :cascade do |t|
@@ -690,6 +691,7 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.integer "cached_markdown_version"
     t.datetime "last_edited_at"
     t.integer "last_edited_by_id"
+    t.integer "head_pipeline_id"
   end
 
   add_index "merge_requests", ["assignee_id"], name: "index_merge_requests_on_assignee_id", using: :btree
diff --git a/spec/lib/gitlab/import_export/safe_model_attributes.yml b/spec/lib/gitlab/import_export/safe_model_attributes.yml
index 3af2a172e6d..d2ceb1cf9ae 100644
--- a/spec/lib/gitlab/import_export/safe_model_attributes.yml
+++ b/spec/lib/gitlab/import_export/safe_model_attributes.yml
@@ -158,6 +158,7 @@ MergeRequest:
 - time_estimate
 - last_edited_at
 - last_edited_by_id
+- head_pipeline_id
 MergeRequestDiff:
 - id
 - state
diff --git a/spec/services/ci/create_pipeline_service_spec.rb b/spec/services/ci/create_pipeline_service_spec.rb
index fa5014cee07..f2ed66b5e8e 100644
--- a/spec/services/ci/create_pipeline_service_spec.rb
+++ b/spec/services/ci/create_pipeline_service_spec.rb
@@ -34,6 +34,18 @@ describe Ci::CreatePipelineService, services: true do
       it { expect(pipeline).to have_attributes(status: 'pending') }
       it { expect(pipeline.builds.first).to be_kind_of(Ci::Build) }
 
+      it 'updates head pipeline of each merge request' do
+        merge_request_1 = create(:merge_request, source_branch: 'master', target_branch: "branch_1", source_project: project)
+        merge_request_2 = create(:merge_request, source_branch: 'master', target_branch: "branch_2", source_project: project)
+        merge_request_3 = create(:merge_request, source_branch: 'other_branch', target_branch: "branch_2", source_project: project)
+
+        head_pipeline = pipeline
+
+        expect(merge_request_1.reload.head_pipeline).to eq(head_pipeline)
+        expect(merge_request_2.reload.head_pipeline).to eq(head_pipeline)
+        expect(merge_request_3.reload.head_pipeline).to be_nil
+      end
+
       context 'auto-cancel enabled' do
         before do
           project.update(auto_cancel_pending_pipelines: 'enabled')

From 85f0b3a984048d1e5d146a233612a0bc96f12b5c Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Wed, 22 Mar 2017 12:20:44 -0300
Subject: [PATCH 2/6] Add merge requests association to pipeline

---
 app/models/ci/pipeline.rb                    | 1 +
 spec/workers/pipeline_metrics_worker_spec.rb | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index db994b861e5..481f9c8dac8 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -17,6 +17,7 @@ module Ci
     has_many :statuses, class_name: 'CommitStatus', foreign_key: :commit_id
     has_many :builds, foreign_key: :commit_id
     has_many :trigger_requests, dependent: :destroy, foreign_key: :commit_id
+    has_many :merge_requests, foreign_key: "head_pipeline_id"
 
     has_many :pending_builds, -> { pending }, foreign_key: :commit_id, class_name: 'Ci::Build'
     has_many :retryable_builds, -> { latest.failed_or_canceled }, foreign_key: :commit_id, class_name: 'Ci::Build'
diff --git a/spec/workers/pipeline_metrics_worker_spec.rb b/spec/workers/pipeline_metrics_worker_spec.rb
index 5dbc0da95c2..dbf2b7251c6 100644
--- a/spec/workers/pipeline_metrics_worker_spec.rb
+++ b/spec/workers/pipeline_metrics_worker_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe PipelineMetricsWorker do
   let(:project) { create(:project, :repository) }
-  let!(:merge_request) { create(:merge_request, source_project: project, source_branch: pipeline.ref) }
+  let!(:merge_request) { create(:merge_request, source_project: project, source_branch: pipeline.ref, head_pipeline_id: pipeline.id) }
 
   let(:pipeline) do
     create(:ci_empty_pipeline,

From 24824cbb4c6d2c5ebd08dea03007f65c5df763da Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Wed, 22 Mar 2017 16:36:14 -0300
Subject: [PATCH 3/6] Fix Specs

---
 changelogs/unreleased/issue_27168_2.yml         |  2 +-
 features/steps/project/merge_requests.rb        |  1 +
 .../projects/merge_requests_controller_spec.rb  |  3 ++-
 spec/features/cycle_analytics_spec.rb           |  5 ++++-
 spec/features/issuables/issuable_list_spec.rb   |  3 +++
 .../merge_immediately_with_pipeline_spec.rb     | 10 ++++++----
 .../merge_when_pipeline_succeeds_spec.rb        |  5 ++++-
 .../merge_requests/mini_pipeline_graph_spec.rb  |  2 +-
 .../only_allow_merge_if_build_succeeds_spec.rb  |  2 ++
 spec/features/merge_requests/widget_spec.rb     | 17 +++++++++++++----
 spec/lib/gitlab/cycle_analytics/events_spec.rb  |  4 ++++
 spec/lib/gitlab/import_export/all_models.yml    |  1 +
 spec/models/ci/pipeline_spec.rb                 |  2 +-
 spec/models/cycle_analytics/test_spec.rb        |  1 +
 spec/models/merge_request_spec.rb               | 16 +++++++---------
 .../projects/cycle_analytics_events_spec.rb     |  1 +
 ...merge_when_pipeline_succeeds_service_spec.rb |  6 ++++++
 .../merge_requests/update_service_spec.rb       |  4 +++-
 18 files changed, 61 insertions(+), 24 deletions(-)

diff --git a/changelogs/unreleased/issue_27168_2.yml b/changelogs/unreleased/issue_27168_2.yml
index c91a95323d5..c67692493e0 100644
--- a/changelogs/unreleased/issue_27168_2.yml
+++ b/changelogs/unreleased/issue_27168_2.yml
@@ -1,4 +1,4 @@
 ---
-title: Preloads head pipeline for each merge request
+title: Preloads head pipeline for merge request collection
 merge_request:
 author:
diff --git a/features/steps/project/merge_requests.rb b/features/steps/project/merge_requests.rb
index 4b7d6cd840b..8bd2065ac34 100644
--- a/features/steps/project/merge_requests.rb
+++ b/features/steps/project/merge_requests.rb
@@ -544,6 +544,7 @@ class Spinach::Features::ProjectMergeRequests < Spinach::FeatureSteps
     project = merge_request.source_project
     project.enable_ci
     pipeline = create :ci_pipeline, project: project, sha: merge_request.diff_head_sha, ref: merge_request.source_branch
+    merge_request.update(head_pipeline: pipeline)
     create :ci_build, pipeline: pipeline
   end
 
diff --git a/spec/controllers/projects/merge_requests_controller_spec.rb b/spec/controllers/projects/merge_requests_controller_spec.rb
index 0483c6b7879..bc13a8123a5 100644
--- a/spec/controllers/projects/merge_requests_controller_spec.rb
+++ b/spec/controllers/projects/merge_requests_controller_spec.rb
@@ -354,7 +354,8 @@ describe Projects::MergeRequestsController do
         end
 
         before do
-          create(:ci_empty_pipeline, project: project, sha: merge_request.diff_head_sha, ref: merge_request.source_branch)
+          pipeline = create(:ci_empty_pipeline, project: project, sha: merge_request.diff_head_sha, ref: merge_request.source_branch)
+          merge_request.update(head_pipeline: pipeline)
         end
 
         it 'returns :merge_when_pipeline_succeeds' do
diff --git a/spec/features/cycle_analytics_spec.rb b/spec/features/cycle_analytics_spec.rb
index df2714f91ff..57826fe872b 100644
--- a/spec/features/cycle_analytics_spec.rb
+++ b/spec/features/cycle_analytics_spec.rb
@@ -9,10 +9,13 @@ feature 'Cycle Analytics', feature: true, js: true do
   let(:mr) { create_merge_request_closing_issue(issue, commit_message: "References #{issue.to_reference}") }
   let(:pipeline) { create(:ci_empty_pipeline, status: 'created', project: project, ref: mr.source_branch, sha: mr.source_branch_sha) }
 
+  before { mr.update(head_pipeline: pipeline) }
+
   context 'as an allowed user' do
     context 'when project is new' do
       before  do
-        project.team << [user, :master]
+        project.add_master(user)
+        mr.update(head_pipeline_id: pipeline.id)
         login_as(user)
         visit namespace_project_cycle_analytics_path(project.namespace, project)
         wait_for_ajax
diff --git a/spec/features/issuables/issuable_list_spec.rb b/spec/features/issuables/issuable_list_spec.rb
index f3ec80bb149..414838fa22e 100644
--- a/spec/features/issuables/issuable_list_spec.rb
+++ b/spec/features/issuables/issuable_list_spec.rb
@@ -52,6 +52,9 @@ describe 'issuable list', feature: true do
           create(:issue, project: project, author: user)
         else
           create(:merge_request, source_project: project, source_branch: generate(:branch))
+          source_branch = FFaker::Name.name
+          pipeline = create(:ci_empty_pipeline, project: project, ref: source_branch, status: %w(running failed success).sample, sha: 'any')
+          create(:merge_request, title: FFaker::Lorem.sentence, source_project: project, source_branch: source_branch, head_pipeline: pipeline)
         end
 
       2.times do
diff --git a/spec/features/merge_requests/merge_immediately_with_pipeline_spec.rb b/spec/features/merge_requests/merge_immediately_with_pipeline_spec.rb
index 497240803d4..4f9a69baad8 100644
--- a/spec/features/merge_requests/merge_immediately_with_pipeline_spec.rb
+++ b/spec/features/merge_requests/merge_immediately_with_pipeline_spec.rb
@@ -4,16 +4,18 @@ feature 'Merge immediately', :feature, :js do
   let(:user) { create(:user) }
   let(:project) { create(:project, :public) }
 
-  let(:merge_request) do
+  let!(:merge_request) do
     create(:merge_request_with_diffs, source_project: project,
                                       author: user,
-                                      title: 'Bug NS-04')
+                                      title: 'Bug NS-04',
+                                      head_pipeline: pipeline,
+                                      source_branch: pipeline.ref)
   end
 
   let(:pipeline) do
     create(:ci_pipeline, project: project,
-                         sha: merge_request.diff_head_sha,
-                         ref: merge_request.source_branch)
+                         ref: 'master',
+                         sha: project.repository.commit('master').id)
   end
 
   before { project.team << [user, :master] }
diff --git a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
index cd540ca113a..9367789c7d4 100644
--- a/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
+++ b/spec/features/merge_requests/merge_when_pipeline_succeeds_spec.rb
@@ -16,7 +16,10 @@ feature 'Merge When Pipeline Succeeds', :feature, :js do
                          ref: merge_request.source_branch)
   end
 
-  before { project.team << [user, :master] }
+  before do
+    project.add_master(user)
+    merge_request.update(head_pipeline_id: pipeline.id)
+  end
 
   context 'when there is active pipeline for merge request' do
     background do
diff --git a/spec/features/merge_requests/mini_pipeline_graph_spec.rb b/spec/features/merge_requests/mini_pipeline_graph_spec.rb
index 449a60c1d05..5b2798af32f 100644
--- a/spec/features/merge_requests/mini_pipeline_graph_spec.rb
+++ b/spec/features/merge_requests/mini_pipeline_graph_spec.rb
@@ -3,7 +3,7 @@ require 'rails_helper'
 feature 'Mini Pipeline Graph', :js, :feature do
   let(:user) { create(:user) }
   let(:project) { create(:project, :public) }
-  let(:merge_request) { create(:merge_request, source_project: project) }
+  let(:merge_request) { create(:merge_request, source_project: project, head_pipeline: pipeline) }
 
   let(:pipeline) { create(:ci_empty_pipeline, project: project, ref: 'master', status: 'running', sha: project.commit.id) }
   let(:build) { create(:ci_build, pipeline: pipeline, stage: 'test', commands: 'test') }
diff --git a/spec/features/merge_requests/only_allow_merge_if_build_succeeds_spec.rb b/spec/features/merge_requests/only_allow_merge_if_build_succeeds_spec.rb
index 4a590e3bf68..981989b0095 100644
--- a/spec/features/merge_requests/only_allow_merge_if_build_succeeds_spec.rb
+++ b/spec/features/merge_requests/only_allow_merge_if_build_succeeds_spec.rb
@@ -27,6 +27,8 @@ feature 'Only allow merge requests to be merged if the pipeline succeeds', featu
       status: status)
     end
 
+    before { merge_request.update(head_pipeline: pipeline) }
+
     context 'when merge requests can only be merged if the pipeline succeeds' do
       before do
         project.update_attribute(:only_allow_merge_if_pipeline_succeeds, true)
diff --git a/spec/features/merge_requests/widget_spec.rb b/spec/features/merge_requests/widget_spec.rb
index d918181a238..02193dbfc8d 100644
--- a/spec/features/merge_requests/widget_spec.rb
+++ b/spec/features/merge_requests/widget_spec.rb
@@ -89,6 +89,8 @@ describe 'Merge request', :feature, :js do
                                       statuses: [commit_status])
       create(:ci_build, :pending, pipeline: pipeline)
 
+      merge_request.update(head_pipeline_id: pipeline.id)
+
       visit namespace_project_merge_request_path(project.namespace, project, merge_request)
     end
 
@@ -101,10 +103,15 @@ describe 'Merge request', :feature, :js do
 
   context 'when merge request is in the blocked pipeline state' do
     before do
-      create(:ci_pipeline, project: project,
-                           sha: merge_request.diff_head_sha,
-                           ref: merge_request.source_branch,
-                           status: :manual)
+      pipeline = create(
+        :ci_pipeline,
+        project: project,
+        sha: merge_request.diff_head_sha,
+        ref: merge_request.source_branch,
+        status: :manual
+      )
+
+      merge_request.update(head_pipeline_id: pipeline.id)
 
       visit namespace_project_merge_request_path(project.namespace,
                                                  project,
@@ -129,6 +136,8 @@ describe 'Merge request', :feature, :js do
                                       statuses: [commit_status])
       create(:ci_build, :pending, pipeline: pipeline)
 
+      merge_request.update(head_pipeline_id: pipeline.id)
+
       visit namespace_project_merge_request_path(project.namespace, project, merge_request)
     end
 
diff --git a/spec/lib/gitlab/cycle_analytics/events_spec.rb b/spec/lib/gitlab/cycle_analytics/events_spec.rb
index 0d56bdd0ebd..8753679e233 100644
--- a/spec/lib/gitlab/cycle_analytics/events_spec.rb
+++ b/spec/lib/gitlab/cycle_analytics/events_spec.rb
@@ -130,6 +130,8 @@ describe 'cycle analytics events' do
     end
 
     before do
+      merge_request.update(head_pipeline_id: pipeline.id)
+
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
 
@@ -226,6 +228,8 @@ describe 'cycle analytics events' do
     end
 
     before do
+      merge_request.update(head_pipeline_id: pipeline.id)
+
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
 
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 688e731bf15..63797c0fc0e 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -85,6 +85,7 @@ merge_requests:
 - merge_requests_closing_issues
 - metrics
 - timelogs
+- head_pipeline
 merge_request_diff:
 - merge_request
 pipelines:
diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index 208c8cb1c3d..86ed37b50aa 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -1044,8 +1044,8 @@ describe Ci::Pipeline, models: true do
     let(:pipeline) { create(:ci_empty_pipeline, status: 'created', project: project, ref: 'master', sha: 'a288a022a53a5a944fae87bcec6efc87b7061808') }
 
     it "returns merge requests whose `diff_head_sha` matches the pipeline's SHA" do
-      merge_request = create(:merge_request, source_project: project, source_branch: pipeline.ref)
       allow_any_instance_of(MergeRequest).to receive(:diff_head_sha) { 'a288a022a53a5a944fae87bcec6efc87b7061808' }
+      merge_request = create(:merge_request, source_project: project, head_pipeline: pipeline, , source_branch: pipeline.ref)
 
       expect(pipeline.merge_requests).to eq([merge_request])
     end
diff --git a/spec/models/cycle_analytics/test_spec.rb b/spec/models/cycle_analytics/test_spec.rb
index c2ba012a0e6..d0b919efcf9 100644
--- a/spec/models/cycle_analytics/test_spec.rb
+++ b/spec/models/cycle_analytics/test_spec.rb
@@ -14,6 +14,7 @@ describe 'CycleAnalytics#test', feature: true do
       issue = context.create(:issue, project: context.project)
       merge_request = context.create_merge_request_closing_issue(issue)
       pipeline = context.create(:ci_pipeline, ref: merge_request.source_branch, sha: merge_request.diff_head_sha, project: context.project)
+      merge_request.update(head_pipeline: pipeline)
       { pipeline: pipeline, issue: issue }
     end,
     start_time_conditions: [["pipeline is started", -> (context, data) { data[:pipeline].run! }]],
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 6cf3dd30ead..45a5cd049a2 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -760,13 +760,9 @@ describe MergeRequest, models: true do
   describe '#head_pipeline' do
     describe 'when the source project exists' do
       it 'returns the latest pipeline' do
-        pipeline = double(:ci_pipeline, ref: 'master')
-
-        allow(subject).to receive(:diff_head_sha).and_return('123abc')
-
-        expect(subject.source_project).to receive(:pipeline_for).
-          with('master', '123abc').
-          and_return(pipeline)
+        sha = "123abc"
+        pipeline = create(:ci_empty_pipeline, project: subject.source_project, ref: 'master', status: 'running', sha: sha)
+        subject.update(head_pipeline: pipeline)
 
         expect(subject.head_pipeline).to eq(pipeline)
       end
@@ -1504,11 +1500,13 @@ describe MergeRequest, models: true do
 
   describe '#mergeable_with_slash_command?' do
     def create_pipeline(status)
-      create(:ci_pipeline_with_one_job,
+      pipeline = create(:ci_pipeline_with_one_job,
         project: project,
         ref:     merge_request.source_branch,
         sha:     merge_request.diff_head_sha,
         status:  status)
+
+      merge_request.update(head_pipeline: pipeline)
     end
 
     let(:project)       { create(:project, :public, :repository, only_allow_merge_if_pipeline_succeeds: true) }
@@ -1594,7 +1592,7 @@ describe MergeRequest, models: true do
 
       context 'with running pipeline'  do
         before do
-          create_pipeline(:running)
+          merge_request.update(head_pipeline: create_pipeline(:running))
         end
 
         it 'is mergeable' do
diff --git a/spec/requests/projects/cycle_analytics_events_spec.rb b/spec/requests/projects/cycle_analytics_events_spec.rb
index c5a45949841..d92daa345b3 100644
--- a/spec/requests/projects/cycle_analytics_events_spec.rb
+++ b/spec/requests/projects/cycle_analytics_events_spec.rb
@@ -122,6 +122,7 @@ describe 'cycle analytics events', api: true do
     mr = create_merge_request_closing_issue(issue, commit_message: "References #{issue.to_reference}")
 
     pipeline = create(:ci_empty_pipeline, status: 'created', project: project, ref: mr.source_branch, sha: mr.source_branch_sha)
+    mr.update(head_pipeline_id: pipeline.id)
     pipeline.run
 
     create(:ci_build, pipeline: pipeline, status: :success, author: user)
diff --git a/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb b/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
index 769b3193275..b0304b3b73f 100644
--- a/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
+++ b/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
@@ -82,6 +82,10 @@ describe MergeRequests::MergeWhenPipelineSucceedsService do
                              sha: merge_request_head, status: 'success')
       end
 
+      before do
+        mr_merge_if_green_enabled.update(head_pipeline: triggering_pipeline)
+      end
+
       it "merges all merge requests with merge when the pipeline succeeds enabled" do
         expect(MergeWorker).to receive(:perform_async)
         service.trigger(triggering_pipeline)
@@ -124,6 +128,8 @@ describe MergeRequests::MergeWhenPipelineSucceedsService do
                              sha: mr_conflict.diff_head_sha, status: 'success')
       end
 
+      before { mr_conflict.update(head_pipeline_id: conflict_pipeline.id) }
+
       it 'does not merge the merge request' do
         expect(MergeWorker).not_to receive(:perform_async)
 
diff --git a/spec/services/merge_requests/update_service_spec.rb b/spec/services/merge_requests/update_service_spec.rb
index 31487c0f794..e5071c2f447 100644
--- a/spec/services/merge_requests/update_service_spec.rb
+++ b/spec/services/merge_requests/update_service_spec.rb
@@ -174,11 +174,13 @@ describe MergeRequests::UpdateService, services: true do
       context 'with active pipeline' do
         before do
           service_mock = double
-          create(:ci_pipeline_with_one_job,
+          pipeline = create(:ci_pipeline_with_one_job,
             project: project,
             ref:     merge_request.source_branch,
             sha:     merge_request.diff_head_sha)
 
+          merge_request.update(head_pipeline_id: pipeline.id)
+
           expect(MergeRequests::MergeWhenPipelineSucceedsService).to receive(:new).with(project, user).
             and_return(service_mock)
           expect(service_mock).to receive(:execute).with(merge_request)

From 1bf2dacf2002fabf3b7bd364031d9020e5d0b624 Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Mon, 27 Mar 2017 19:19:28 -0300
Subject: [PATCH 4/6] Populate merge requests head_pipeline_id

---
 ...dd_head_pipeline_for_each_merge_request.rb | 23 +++++++++++++++++++
 db/schema.rb                                  |  2 +-
 2 files changed, 24 insertions(+), 1 deletion(-)
 create mode 100644 db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb

diff --git a/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb b/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
new file mode 100644
index 00000000000..0e139c28402
--- /dev/null
+++ b/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
@@ -0,0 +1,23 @@
+class AddHeadPipelineForEachMergeRequest < ActiveRecord::Migration
+  DOWNTIME = false
+
+  class Pipeline < ActiveRecord::Base
+    self.table_name = "ci_pipelines"
+
+    def self.last_per_branch
+      select('ref, MAX(id) as head_id, project_id').group(:ref).group(:project_id)
+    end
+  end
+
+  class MergeRequest < ActiveRecord::Base; end
+
+  def up
+    Pipeline.last_per_branch.each do |pipeline|
+      mrs = MergeRequest.where(source_branch: pipeline.ref, source_project_id: pipeline.project_id)
+      mrs.update_all(head_pipeline_id: pipeline.head_id)
+    end
+  end
+
+  def down
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index d5b1d3bb0d8..d0e10f00ffd 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -114,6 +114,7 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.string "plantuml_url"
     t.boolean "plantuml_enabled"
     t.integer "terminal_max_session_time", default: 0, null: false
+    t.string "default_artifacts_expire_in", default: "0", null: false
     t.integer "unique_ips_limit_per_user"
     t.integer "unique_ips_limit_time_window"
     t.boolean "unique_ips_limit_enabled", default: false, null: false
@@ -123,7 +124,6 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.integer "cached_markdown_version"
     t.boolean "clientside_sentry_enabled", default: false, null: false
     t.string "clientside_sentry_dsn"
-    t.string "default_artifacts_expire_in", default: "0", null: false
   end
 
   create_table "audit_events", force: :cascade do |t|

From d9bebd89dfcf7e4b163b271eea3d7a5c3e99fb5d Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Tue, 28 Mar 2017 17:04:14 -0300
Subject: [PATCH 5/6] Fix specs 2

---
 app/models/ci/pipeline.rb                     | 11 ++-----
 ...dd_head_pipeline_for_each_merge_request.rb | 30 ++++++++++---------
 .../merge_requests_controller_spec.rb         |  5 +++-
 spec/features/cycle_analytics_spec.rb         | 13 ++++----
 spec/features/merge_requests/widget_spec.rb   |  6 ++--
 .../lib/gitlab/cycle_analytics/events_spec.rb |  4 +--
 spec/models/ci/pipeline_spec.rb               |  2 +-
 spec/models/merge_request_spec.rb             |  4 ++-
 ...rge_when_pipeline_succeeds_service_spec.rb |  2 +-
 .../merge_requests/update_service_spec.rb     |  2 +-
 spec/workers/pipeline_metrics_worker_spec.rb  |  2 +-
 11 files changed, 43 insertions(+), 38 deletions(-)

diff --git a/app/models/ci/pipeline.rb b/app/models/ci/pipeline.rb
index 481f9c8dac8..81c30b0e077 100644
--- a/app/models/ci/pipeline.rb
+++ b/app/models/ci/pipeline.rb
@@ -17,6 +17,9 @@ module Ci
     has_many :statuses, class_name: 'CommitStatus', foreign_key: :commit_id
     has_many :builds, foreign_key: :commit_id
     has_many :trigger_requests, dependent: :destroy, foreign_key: :commit_id
+
+    # Merge requests for which the current pipeline is running against
+    # the merge request's latest commit.
     has_many :merge_requests, foreign_key: "head_pipeline_id"
 
     has_many :pending_builds, -> { pending }, foreign_key: :commit_id, class_name: 'Ci::Build'
@@ -382,14 +385,6 @@ module Ci
       project.execute_services(data, :pipeline_hooks)
     end
 
-    # Merge requests for which the current pipeline is running against
-    # the merge request's latest commit.
-    def merge_requests
-      @merge_requests ||= project.merge_requests
-        .where(source_branch: self.ref)
-        .select { |merge_request| merge_request.head_pipeline.try(:id) == self.id }
-    end
-
     # All the merge requests for which the current pipeline runs/ran against
     def all_merge_requests
       @all_merge_requests ||= project.merge_requests.where(source_branch: ref)
diff --git a/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb b/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
index 0e139c28402..bc3850c0c23 100644
--- a/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
+++ b/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
@@ -1,21 +1,23 @@
 class AddHeadPipelineForEachMergeRequest < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
   DOWNTIME = false
 
-  class Pipeline < ActiveRecord::Base
-    self.table_name = "ci_pipelines"
-
-    def self.last_per_branch
-      select('ref, MAX(id) as head_id, project_id').group(:ref).group(:project_id)
-    end
-  end
-
-  class MergeRequest < ActiveRecord::Base; end
-
   def up
-    Pipeline.last_per_branch.each do |pipeline|
-      mrs = MergeRequest.where(source_branch: pipeline.ref, source_project_id: pipeline.project_id)
-      mrs.update_all(head_pipeline_id: pipeline.head_id)
-    end
+    disable_statement_timeout
+
+    pipelines = Arel::Table.new(:ci_pipelines)
+    merge_requests = Arel::Table.new(:merge_requests)
+
+    head_id = pipelines.
+      project(Arel::Nodes::NamedFunction.new('max', [pipelines[:id]])).
+      from(pipelines).
+      where(pipelines[:ref].eq(merge_requests[:source_branch])).
+      where(pipelines[:project_id].eq(merge_requests[:source_project_id]))
+
+    sub_query = Arel::Nodes::SqlLiteral.new(Arel::Nodes::Grouping.new(head_id).to_sql)
+
+    update_column_in_batches(:merge_requests, :head_pipeline_id, sub_query)
   end
 
   def down
diff --git a/spec/controllers/projects/merge_requests_controller_spec.rb b/spec/controllers/projects/merge_requests_controller_spec.rb
index bc13a8123a5..d9dae999a87 100644
--- a/spec/controllers/projects/merge_requests_controller_spec.rb
+++ b/spec/controllers/projects/merge_requests_controller_spec.rb
@@ -1200,7 +1200,10 @@ describe Projects::MergeRequestsController do
 
       let(:status) { pipeline.detailed_status(double('user')) }
 
-      before { get_pipeline_status }
+      before do
+        merge_request.update(head_pipeline: pipeline)
+        get_pipeline_status
+      end
 
       it 'return a detailed head_pipeline status in json' do
         expect(response).to have_http_status(:ok)
diff --git a/spec/features/cycle_analytics_spec.rb b/spec/features/cycle_analytics_spec.rb
index 57826fe872b..5553687707d 100644
--- a/spec/features/cycle_analytics_spec.rb
+++ b/spec/features/cycle_analytics_spec.rb
@@ -9,14 +9,17 @@ feature 'Cycle Analytics', feature: true, js: true do
   let(:mr) { create_merge_request_closing_issue(issue, commit_message: "References #{issue.to_reference}") }
   let(:pipeline) { create(:ci_empty_pipeline, status: 'created', project: project, ref: mr.source_branch, sha: mr.source_branch_sha) }
 
-  before { mr.update(head_pipeline: pipeline) }
+  before do
+    allow_any_instance_of(Gitlab::ReferenceExtractor).to receive(:issues).and_return([issue])
+  end
 
   context 'as an allowed user' do
     context 'when project is new' do
       before  do
         project.add_master(user)
-        mr.update(head_pipeline_id: pipeline.id)
+
         login_as(user)
+
         visit namespace_project_cycle_analytics_path(project.namespace, project)
         wait_for_ajax
       end
@@ -33,8 +36,8 @@ feature 'Cycle Analytics', feature: true, js: true do
 
     context "when there's cycle analytics data" do
       before do
-        project.team << [user, :master]
-
+        mr.update(head_pipeline: pipeline)
+        project.add_master(user)
         create_cycle
         deploy_master
 
@@ -87,7 +90,7 @@ feature 'Cycle Analytics', feature: true, js: true do
 
   context "as a guest" do
     before do
-      project.team << [guest, :guest]
+      project.add_guest(guest)
 
       allow_any_instance_of(Gitlab::ReferenceExtractor).to receive(:issues).and_return([issue])
       create_cycle
diff --git a/spec/features/merge_requests/widget_spec.rb b/spec/features/merge_requests/widget_spec.rb
index 02193dbfc8d..b1255ac0bd5 100644
--- a/spec/features/merge_requests/widget_spec.rb
+++ b/spec/features/merge_requests/widget_spec.rb
@@ -89,7 +89,7 @@ describe 'Merge request', :feature, :js do
                                       statuses: [commit_status])
       create(:ci_build, :pending, pipeline: pipeline)
 
-      merge_request.update(head_pipeline_id: pipeline.id)
+      merge_request.update(head_pipeline: pipeline)
 
       visit namespace_project_merge_request_path(project.namespace, project, merge_request)
     end
@@ -111,7 +111,7 @@ describe 'Merge request', :feature, :js do
         status: :manual
       )
 
-      merge_request.update(head_pipeline_id: pipeline.id)
+      merge_request.update(head_pipeline: pipeline)
 
       visit namespace_project_merge_request_path(project.namespace,
                                                  project,
@@ -136,7 +136,7 @@ describe 'Merge request', :feature, :js do
                                       statuses: [commit_status])
       create(:ci_build, :pending, pipeline: pipeline)
 
-      merge_request.update(head_pipeline_id: pipeline.id)
+      merge_request.update(head_pipeline: pipeline)
 
       visit namespace_project_merge_request_path(project.namespace, project, merge_request)
     end
diff --git a/spec/lib/gitlab/cycle_analytics/events_spec.rb b/spec/lib/gitlab/cycle_analytics/events_spec.rb
index 8753679e233..3610a0354e8 100644
--- a/spec/lib/gitlab/cycle_analytics/events_spec.rb
+++ b/spec/lib/gitlab/cycle_analytics/events_spec.rb
@@ -130,7 +130,7 @@ describe 'cycle analytics events' do
     end
 
     before do
-      merge_request.update(head_pipeline_id: pipeline.id)
+      merge_request.update(head_pipeline: pipeline)
 
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
@@ -228,7 +228,7 @@ describe 'cycle analytics events' do
     end
 
     before do
-      merge_request.update(head_pipeline_id: pipeline.id)
+      merge_request.update(head_pipeline: pipeline)
 
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
       create(:ci_build, pipeline: pipeline, status: :success, author: user)
diff --git a/spec/models/ci/pipeline_spec.rb b/spec/models/ci/pipeline_spec.rb
index 86ed37b50aa..06e990a0574 100644
--- a/spec/models/ci/pipeline_spec.rb
+++ b/spec/models/ci/pipeline_spec.rb
@@ -1045,7 +1045,7 @@ describe Ci::Pipeline, models: true do
 
     it "returns merge requests whose `diff_head_sha` matches the pipeline's SHA" do
       allow_any_instance_of(MergeRequest).to receive(:diff_head_sha) { 'a288a022a53a5a944fae87bcec6efc87b7061808' }
-      merge_request = create(:merge_request, source_project: project, head_pipeline: pipeline, , source_branch: pipeline.ref)
+      merge_request = create(:merge_request, source_project: project, head_pipeline: pipeline, source_branch: pipeline.ref)
 
       expect(pipeline.merge_requests).to eq([merge_request])
     end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 45a5cd049a2..1db1640f5e5 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -1507,6 +1507,8 @@ describe MergeRequest, models: true do
         status:  status)
 
       merge_request.update(head_pipeline: pipeline)
+
+      pipeline
     end
 
     let(:project)       { create(:project, :public, :repository, only_allow_merge_if_pipeline_succeeds: true) }
@@ -1592,7 +1594,7 @@ describe MergeRequest, models: true do
 
       context 'with running pipeline'  do
         before do
-          merge_request.update(head_pipeline: create_pipeline(:running))
+          create_pipeline(:running)
         end
 
         it 'is mergeable' do
diff --git a/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb b/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
index b0304b3b73f..3ef5135e6a3 100644
--- a/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
+++ b/spec/services/merge_requests/merge_when_pipeline_succeeds_service_spec.rb
@@ -128,7 +128,7 @@ describe MergeRequests::MergeWhenPipelineSucceedsService do
                              sha: mr_conflict.diff_head_sha, status: 'success')
       end
 
-      before { mr_conflict.update(head_pipeline_id: conflict_pipeline.id) }
+      before { mr_conflict.update(head_pipeline: conflict_pipeline) }
 
       it 'does not merge the merge request' do
         expect(MergeWorker).not_to receive(:perform_async)
diff --git a/spec/services/merge_requests/update_service_spec.rb b/spec/services/merge_requests/update_service_spec.rb
index e5071c2f447..07f5440cc36 100644
--- a/spec/services/merge_requests/update_service_spec.rb
+++ b/spec/services/merge_requests/update_service_spec.rb
@@ -179,7 +179,7 @@ describe MergeRequests::UpdateService, services: true do
             ref:     merge_request.source_branch,
             sha:     merge_request.diff_head_sha)
 
-          merge_request.update(head_pipeline_id: pipeline.id)
+          merge_request.update(head_pipeline: pipeline)
 
           expect(MergeRequests::MergeWhenPipelineSucceedsService).to receive(:new).with(project, user).
             and_return(service_mock)
diff --git a/spec/workers/pipeline_metrics_worker_spec.rb b/spec/workers/pipeline_metrics_worker_spec.rb
index dbf2b7251c6..ef71125c0b6 100644
--- a/spec/workers/pipeline_metrics_worker_spec.rb
+++ b/spec/workers/pipeline_metrics_worker_spec.rb
@@ -2,7 +2,7 @@ require 'spec_helper'
 
 describe PipelineMetricsWorker do
   let(:project) { create(:project, :repository) }
-  let!(:merge_request) { create(:merge_request, source_project: project, source_branch: pipeline.ref, head_pipeline_id: pipeline.id) }
+  let!(:merge_request) { create(:merge_request, source_project: project, source_branch: pipeline.ref, head_pipeline: pipeline) }
 
   let(:pipeline) do
     create(:ci_empty_pipeline,

From 2ccee7161a58ea04c66b216ccb57e522850f5d95 Mon Sep 17 00:00:00 2001
From: Felipe Artur <felipefac@gmail.com>
Date: Fri, 5 May 2017 16:00:18 -0300
Subject: [PATCH 6/6] Small code improvements and add migration spec

---
 app/services/ci/create_pipeline_service.rb    |  5 +--
 ...add_head_pipeline_id_to_merge_requests.rb} |  0
 ...d_head_pipeline_for_each_merge_request.rb} |  0
 db/schema.rb                                  |  3 +-
 spec/features/cycle_analytics_spec.rb         |  6 +--
 spec/lib/gitlab/import_export/all_models.yml  |  1 +
 ...ad_pipeline_for_each_merge_request_spec.rb | 33 +++++++++++++++
 spec/models/merge_request_spec.rb             |  3 +-
 .../ci/create_pipeline_service_spec.rb        | 40 +++++++++++++++----
 9 files changed, 72 insertions(+), 19 deletions(-)
 rename db/migrate/{20170427205316_add_head_pipeline_id_to_merge_requests.rb => 20170507205316_add_head_pipeline_id_to_merge_requests.rb} (100%)
 rename db/post_migrate/{20170428170547_add_head_pipeline_for_each_merge_request.rb => 20170508170547_add_head_pipeline_for_each_merge_request.rb} (100%)
 create mode 100644 spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb

diff --git a/app/services/ci/create_pipeline_service.rb b/app/services/ci/create_pipeline_service.rb
index 26b744ae3c4..1f6c1f4a7f6 100644
--- a/app/services/ci/create_pipeline_service.rb
+++ b/app/services/ci/create_pipeline_service.rb
@@ -119,9 +119,8 @@ module Ci
     end
 
     def update_merge_requests_head_pipeline
-      merge_requests = MergeRequest.where(source_branch: @pipeline.ref, source_project: @pipeline.project)
-
-      merge_requests.update_all(head_pipeline_id: @pipeline.id) if merge_requests.any?
+      MergeRequest.where(source_branch: @pipeline.ref, source_project: @pipeline.project).
+        update_all(head_pipeline_id: @pipeline.id)
     end
 
     def error(message, save: false)
diff --git a/db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb b/db/migrate/20170507205316_add_head_pipeline_id_to_merge_requests.rb
similarity index 100%
rename from db/migrate/20170427205316_add_head_pipeline_id_to_merge_requests.rb
rename to db/migrate/20170507205316_add_head_pipeline_id_to_merge_requests.rb
diff --git a/db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb b/db/post_migrate/20170508170547_add_head_pipeline_for_each_merge_request.rb
similarity index 100%
rename from db/post_migrate/20170428170547_add_head_pipeline_for_each_merge_request.rb
rename to db/post_migrate/20170508170547_add_head_pipeline_for_each_merge_request.rb
diff --git a/db/schema.rb b/db/schema.rb
index d0e10f00ffd..b91b3e6e977 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20170506185517) do
+ActiveRecord::Schema.define(version: 20170508170547) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -114,7 +114,6 @@ ActiveRecord::Schema.define(version: 20170506185517) do
     t.string "plantuml_url"
     t.boolean "plantuml_enabled"
     t.integer "terminal_max_session_time", default: 0, null: false
-    t.string "default_artifacts_expire_in", default: "0", null: false
     t.integer "unique_ips_limit_per_user"
     t.integer "unique_ips_limit_time_window"
     t.boolean "unique_ips_limit_enabled", default: false, null: false
diff --git a/spec/features/cycle_analytics_spec.rb b/spec/features/cycle_analytics_spec.rb
index 5553687707d..cbeb73d9cae 100644
--- a/spec/features/cycle_analytics_spec.rb
+++ b/spec/features/cycle_analytics_spec.rb
@@ -9,10 +9,6 @@ feature 'Cycle Analytics', feature: true, js: true do
   let(:mr) { create_merge_request_closing_issue(issue, commit_message: "References #{issue.to_reference}") }
   let(:pipeline) { create(:ci_empty_pipeline, status: 'created', project: project, ref: mr.source_branch, sha: mr.source_branch_sha) }
 
-  before do
-    allow_any_instance_of(Gitlab::ReferenceExtractor).to receive(:issues).and_return([issue])
-  end
-
   context 'as an allowed user' do
     context 'when project is new' do
       before  do
@@ -36,8 +32,10 @@ feature 'Cycle Analytics', feature: true, js: true do
 
     context "when there's cycle analytics data" do
       before do
+        allow_any_instance_of(Gitlab::ReferenceExtractor).to receive(:issues).and_return([issue])
         mr.update(head_pipeline: pipeline)
         project.add_master(user)
+
         create_cycle
         deploy_master
 
diff --git a/spec/lib/gitlab/import_export/all_models.yml b/spec/lib/gitlab/import_export/all_models.yml
index 63797c0fc0e..34f617e23a5 100644
--- a/spec/lib/gitlab/import_export/all_models.yml
+++ b/spec/lib/gitlab/import_export/all_models.yml
@@ -103,6 +103,7 @@ pipelines:
 - manual_actions
 - artifacts
 - pipeline_schedule
+- merge_requests
 statuses:
 - project
 - pipeline
diff --git a/spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb b/spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb
new file mode 100644
index 00000000000..bd5f85b901d
--- /dev/null
+++ b/spec/migrations/add_head_pipeline_for_each_merge_request_spec.rb
@@ -0,0 +1,33 @@
+require 'spec_helper'
+require Rails.root.join('db', 'post_migrate', '20170508170547_add_head_pipeline_for_each_merge_request.rb')
+
+describe AddHeadPipelineForEachMergeRequest do
+  let(:migration) { described_class.new }
+
+  let!(:project) { create(:empty_project) }
+  let!(:forked_project_link) { create(:forked_project_link, forked_from_project: project) }
+  let!(:other_project) { forked_project_link.forked_to_project }
+
+  let!(:pipeline_1) { create(:ci_pipeline, project: project, ref: "branch_1") }
+  let!(:pipeline_2) { create(:ci_pipeline, project: other_project, ref: "branch_1") }
+  let!(:pipeline_3) { create(:ci_pipeline, project: other_project, ref: "branch_1") }
+  let!(:pipeline_4) { create(:ci_pipeline, project: project, ref: "branch_2") }
+
+  let!(:mr_1) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_1", target_branch: "target_1") }
+  let!(:mr_2) { create(:merge_request, source_project: other_project, target_project: project, source_branch: "branch_1", target_branch: "target_2") }
+  let!(:mr_3) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_2", target_branch: "master") }
+  let!(:mr_4) { create(:merge_request, source_project: project, target_project: project, source_branch: "branch_3", target_branch: "master") }
+
+  context "#up" do
+    context "when source_project and source_branch of pipeline are the same of merge request" do
+      it "sets head_pipeline_id of given merge requests" do
+        migration.up
+
+        expect(mr_1.reload.head_pipeline_id).to eq(pipeline_1.id)
+        expect(mr_2.reload.head_pipeline_id).to eq(pipeline_3.id)
+        expect(mr_3.reload.head_pipeline_id).to eq(pipeline_4.id)
+        expect(mr_4.reload.head_pipeline_id).to be_nil
+      end
+    end
+  end
+end
diff --git a/spec/models/merge_request_spec.rb b/spec/models/merge_request_spec.rb
index 1db1640f5e5..ef349530761 100644
--- a/spec/models/merge_request_spec.rb
+++ b/spec/models/merge_request_spec.rb
@@ -760,8 +760,7 @@ describe MergeRequest, models: true do
   describe '#head_pipeline' do
     describe 'when the source project exists' do
       it 'returns the latest pipeline' do
-        sha = "123abc"
-        pipeline = create(:ci_empty_pipeline, project: subject.source_project, ref: 'master', status: 'running', sha: sha)
+        pipeline = create(:ci_empty_pipeline, project: subject.source_project, ref: 'master', status: 'running', sha: "123abc")
         subject.update(head_pipeline: pipeline)
 
         expect(subject.head_pipeline).to eq(pipeline)
diff --git a/spec/services/ci/create_pipeline_service_spec.rb b/spec/services/ci/create_pipeline_service_spec.rb
index f2ed66b5e8e..1ff1438ba06 100644
--- a/spec/services/ci/create_pipeline_service_spec.rb
+++ b/spec/services/ci/create_pipeline_service_spec.rb
@@ -34,16 +34,40 @@ describe Ci::CreatePipelineService, services: true do
       it { expect(pipeline).to have_attributes(status: 'pending') }
       it { expect(pipeline.builds.first).to be_kind_of(Ci::Build) }
 
-      it 'updates head pipeline of each merge request' do
-        merge_request_1 = create(:merge_request, source_branch: 'master', target_branch: "branch_1", source_project: project)
-        merge_request_2 = create(:merge_request, source_branch: 'master', target_branch: "branch_2", source_project: project)
-        merge_request_3 = create(:merge_request, source_branch: 'other_branch', target_branch: "branch_2", source_project: project)
+      context '#update_merge_requests_head_pipeline' do
+        it 'updates head pipeline of each merge request' do
+          merge_request_1 = create(:merge_request, source_branch: 'master', target_branch: "branch_1", source_project: project)
+          merge_request_2 = create(:merge_request, source_branch: 'master', target_branch: "branch_2", source_project: project)
 
-        head_pipeline = pipeline
+          head_pipeline = pipeline
 
-        expect(merge_request_1.reload.head_pipeline).to eq(head_pipeline)
-        expect(merge_request_2.reload.head_pipeline).to eq(head_pipeline)
-        expect(merge_request_3.reload.head_pipeline).to be_nil
+          expect(merge_request_1.reload.head_pipeline).to eq(head_pipeline)
+          expect(merge_request_2.reload.head_pipeline).to eq(head_pipeline)
+        end
+
+        context 'when there is no pipeline for source branch' do
+          it "does not update merge request head pipeline" do
+            merge_request = create(:merge_request, source_branch: 'other_branch', target_branch: "branch_1", source_project: project)
+
+            head_pipeline = pipeline
+
+            expect(merge_request.reload.head_pipeline).not_to eq(head_pipeline)
+          end
+        end
+
+        context 'when merge request target project is different from source project' do
+          let!(:target_project) { create(:empty_project) }
+          let!(:forked_project_link) { create(:forked_project_link, forked_to_project: project, forked_from_project: target_project) }
+
+          it 'updates head pipeline for merge request' do
+            merge_request =
+              create(:merge_request, source_branch: 'master', target_branch: "branch_1", source_project: project, target_project: target_project)
+
+            head_pipeline = pipeline
+
+            expect(merge_request.reload.head_pipeline).to eq(head_pipeline)
+          end
+        end
       end
 
       context 'auto-cancel enabled' do