Check redirecting with a querystring

lib/gitlab/routing.rb

@@ -44,8 +44,10 @@ module Gitlab
     def self.redirect_legacy_paths(router, *paths)
       build_redirect_path = lambda do |request, _params, path|
         # Only replace the last occurence of `path`.
-        path = request.fullpath.sub(%r{/#{path}/*(?!.*#{path})}, "/-/#{path}/")
-        path << request.query_string if request.query_string.present?
+        #
+        # `request.fullpath` includes the querystring
+        path = request.path.sub(%r{/#{path}/*(?!.*#{path})}, "/-/#{path}/")
+        path << "?#{request.query_string}" if request.query_string.present?
 
         path
       end

spec/routing/group_routing_spec.rb

@@ -74,6 +74,16 @@ describe "Groups", "routing" do
           expect(request).to redirect_to("/groups/#{group_path}/-/milestones/#{milestone.id}/merge_requests")
         end
       end
+
+      context 'with a query string' do
+        it_behaves_like 'redirecting a legacy path', "/groups/complex.group-namegit/milestones?hello=world", "/groups/complex.group-namegit/-/milestones/?hello=world" do
+          let(:resource) { create(:group, parent: group, path: 'milestones') }
+        end
+
+        it_behaves_like 'redirecting a legacy path', "/groups/complex.group-namegit/milestones?milestones=/milestones", "/groups/complex.group-namegit/-/milestones/?milestones=/milestones" do
+          let(:resource) { create(:group, parent: group, path: 'milestones') }
+        end
+      end
     end
 
     describe 'edit' do