Merge branch '37354-pipelines-update' into 'master'

Make sure head pippeline always corresponds with an MR

Closes #37354

See merge request gitlab-org/gitlab-ce!14358

7 files changed, 49 insertions, 12 deletions

diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index abe4e5245b1..37acd1c9787 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -283,15 +283,15 @@ class Projects::MergeRequestsController < Projects::MergeRequests::ApplicationCo
     @merge_request.update(merge_error: nil)
 
     if params[:merge_when_pipeline_succeeds].present?
-      return :failed unless @merge_request.head_pipeline
+      return :failed unless @merge_request.actual_head_pipeline
 
-      if @merge_request.head_pipeline.active?
+      if @merge_request.actual_head_pipeline.active?
         ::MergeRequests::MergeWhenPipelineSucceedsService
           .new(@project, current_user, merge_params)
           .execute(@merge_request)
 
         :merge_when_pipeline_succeeds
-      elsif @merge_request.head_pipeline.success?
+      elsif @merge_request.actual_head_pipeline.success?
         # This can be triggered when a user clicks the auto merge button while
         # the tests finish at about the same time
         @merge_request.merge_async(current_user.id, params)
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index bbc01e9677c..f2d639a3382 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -145,6 +145,13 @@ class MergeRequest < ActiveRecord::Base
     '!'
   end
 
+  # Use this method whenever you need to make sure the head_pipeline is synced with the
+  # branch head commit, for example checking if a merge request can be merged.
+  # For more information check: https://gitlab.com/gitlab-org/gitlab-ce/issues/40004
+  def actual_head_pipeline
+    head_pipeline&.sha == diff_head_sha ? head_pipeline : nil
+  end
+
   # Pattern used to extract `!123` merge request references from text
   #
   # This pattern supports cross-project references.
@@ -822,8 +829,9 @@ class MergeRequest < ActiveRecord::Base
 
   def mergeable_ci_state?
     return true unless project.only_allow_merge_if_pipeline_succeeds?
+    return true unless head_pipeline
 
-    !head_pipeline || head_pipeline.success? || head_pipeline.skipped?
+    actual_head_pipeline&.success? || actual_head_pipeline&.skipped?
   end
 
   def environments_for(current_user)
@@ -997,7 +1005,7 @@ class MergeRequest < ActiveRecord::Base
     return true if autocomplete_precheck
 
     return false unless mergeable?(skip_ci_check: true)
-    return false if head_pipeline && !(head_pipeline.success? || head_pipeline.active?)
+    return false if actual_head_pipeline && !(actual_head_pipeline.success? || actual_head_pipeline.active?)
     return false if last_diff_sha != diff_head_sha
 
     true
diff --git a/app/presenters/merge_request_presenter.rb b/app/presenters/merge_request_presenter.rb
index a25882cbb62..ab4c87c0169 100644
--- a/app/presenters/merge_request_presenter.rb
+++ b/app/presenters/merge_request_presenter.rb
@@ -163,7 +163,7 @@ class MergeRequestPresenter < Gitlab::View::Presenter::Delegated
   end
 
   def pipeline
-    @pipeline ||= head_pipeline
+    @pipeline ||= actual_head_pipeline
   end
 
   def issues_sentence(project, issues)
diff --git a/app/serializers/merge_request_entity.rb b/app/serializers/merge_request_entity.rb
index b53a49fe59e..eece9445dca 100644
--- a/app/serializers/merge_request_entity.rb
+++ b/app/serializers/merge_request_entity.rb
@@ -33,7 +33,7 @@ class MergeRequestEntity < IssuableEntity
   end
 
   expose :merge_commit_message
-  expose :head_pipeline, with: PipelineDetailsEntity, as: :pipeline
+  expose :actual_head_pipeline, with: PipelineDetailsEntity, as: :pipeline
 
   # Booleans
   expose :merge_ongoing?, as: :merge_ongoing
diff --git a/app/services/ci/create_pipeline_service.rb b/app/services/ci/create_pipeline_service.rb
index 7b9ea223d26..1e5f2ed4dd2 100644
--- a/app/services/ci/create_pipeline_service.rb
+++ b/app/services/ci/create_pipeline_service.rb
@@ -29,7 +29,7 @@ module Ci
         .new(pipeline, command, SEQUENCE)
 
       sequence.build! do |pipeline, sequence|
-        update_merge_requests_head_pipeline if pipeline.persisted?
+        schedule_head_pipeline_update
 
         if sequence.complete?
           cancel_pending_pipelines if project.auto_cancel_pending_pipelines?
@@ -38,15 +38,18 @@ module Ci
           pipeline.process!
         end
       end
+
+      pipeline
     end
 
     private
 
-    def update_merge_requests_head_pipeline
-      return unless pipeline.latest?
+    def commit
+      @commit ||= project.commit(origin_sha || origin_ref)
+    end
 
-      MergeRequest.where(source_project: @pipeline.project, source_branch: @pipeline.ref)
-        .update_all(head_pipeline_id: @pipeline.id)
+    def sha
+      commit.try(:id)
     end
 
     def cancel_pending_pipelines
@@ -69,5 +72,15 @@ module Ci
       @pipeline_created_counter ||= Gitlab::Metrics
         .counter(:pipelines_created_total, "Counter of pipelines created")
     end
+
+    def schedule_head_pipeline_update
+      related_merge_requests.each do |merge_request|
+        UpdateHeadPipelineForMergeRequestWorker.perform_async(merge_request.id)
+      end
+    end
+
+    def related_merge_requests
+      MergeRequest.where(source_project: pipeline.project, source_branch: pipeline.ref)
+    end
   end
 end
diff --git a/app/services/merge_requests/refresh_service.rb b/app/services/merge_requests/refresh_service.rb
index bf3d4855122..434dda89db0 100644
--- a/app/services/merge_requests/refresh_service.rb
+++ b/app/services/merge_requests/refresh_service.rb
@@ -76,6 +76,7 @@ module MergeRequests
         end
 
         merge_request.mark_as_unchecked
+        UpdateHeadPipelineForMergeRequestWorker.perform_async(merge_request.id)
       end
     end
 
diff --git a/app/workers/update_head_pipeline_for_merge_request_worker.rb b/app/workers/update_head_pipeline_for_merge_request_worker.rb
new file mode 100644
index 00000000000..0a2e9b63578
--- /dev/null
+++ b/app/workers/update_head_pipeline_for_merge_request_worker.rb
@@ -0,0 +1,15 @@
+class UpdateHeadPipelineForMergeRequestWorker
+  include ApplicationWorker
+
+  sidekiq_options queue: 'pipeline_default'
+
+  def perform(merge_request_id)
+    merge_request = MergeRequest.find(merge_request_id)
+    pipeline = Ci::Pipeline.where(project: merge_request.source_project, ref: merge_request.source_branch).last
+
+    return unless pipeline && pipeline.latest?
+    raise ArgumentError, 'merge request sha does not equal pipeline sha' if merge_request.diff_head_sha != pipeline.sha
+
+    merge_request.update_attribute(:head_pipeline_id, pipeline.id)
+  end
+end