fixed：同一方向pullrequest不允许存在

app/controllers/api/v1/projects/pulls/pulls_controller.rb

@@ -14,6 +14,13 @@ class Api::V1::Projects::Pulls::PullsController < Api::V1::BaseController
   end
 
   def reopen
+    can_merge = @project&.pull_requests.where(head: @pull_request.head, base: @pull_request.base, status: 0, is_original: @pull_request.is_original, fork_project_id: @pull_request.fork_project_id)
+    if can_merge.present?
+      render json: {
+        status: -2,
+        message: "在这些分支之间的合并请求已存在：<a href='/#{@project.owner.login}/#{@project.identifier}/pulls/#{can_merge.first.id}''>#{can_merge.first.try(:title)}</a>",
+      }
+    else
       @result_object = Api::V1::Projects::Pulls::ReopenService.call(@project, @pull_request, current_user)
       if @result_object
         render_ok
@@ -21,6 +28,7 @@ class Api::V1::Projects::Pulls::PullsController < Api::V1::BaseController
         render_error("合并请求重新打开失败！")
       end
     end
+  end
 
   def files
     if params[:filepath].present?