1 files changed, 37 insertions, 0 deletions
diff --git a/app/services/merge_requests/create_pipeline_service.rb b/app/services/merge_requests/create_pipeline_service.rb
new file mode 100644
index 00000000000..03246cc1920
--- /dev/null
+++ b/app/services/merge_requests/create_pipeline_service.rb
@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+module MergeRequests
+  class CreatePipelineService < MergeRequests::BaseService
+    def execute(merge_request)
+      return unless can_create_pipeline_for?(merge_request)
+
+      create_detached_merge_request_pipeline(merge_request)
+    end
+
+    def create_detached_merge_request_pipeline(merge_request)
+      if can_use_merge_request_ref?(merge_request)
+        Ci::CreatePipelineService.new(merge_request.source_project, current_user,
+                                      ref: merge_request.ref_path)
+          .execute(:merge_request_event, merge_request: merge_request)
+      else
+        Ci::CreatePipelineService.new(merge_request.source_project, current_user,
+                                      ref: merge_request.source_branch)
+          .execute(:merge_request_event, merge_request: merge_request)
+      end
+    end
+
+    def can_create_pipeline_for?(merge_request)
+      ##
+      # UpdateMergeRequestsWorker could be retried by an exception.
+      # pipelines for merge request should not be recreated in such case.
+      return false if !allow_duplicate && merge_request.find_actual_head_pipeline&.triggered_by_merge_request?
+      return false if merge_request.has_no_commits?
+
+      true
+    end
+
+    def allow_duplicate
+      params[:allow_duplicate]
+    end
+  end
+end