Undefined index: test_name

When we run arc diff sometime we got error msg like

[2021-01-04 14:54:57] EXCEPTION: (RuntimeException) Undefined index: test_name at [<arcanist>/src/error/PhutilErrorHandler.php:253]
arcanist(head=master, ref.master=4b3baca999a4), arcanist-extensions()
  #0 PhutilErrorHandler::handleError(integer, string, string, integer, array) called at [<arcanist-extensions>/src/unit/parser/ArcanistGoTestResultParser.php:115]
  #1 ArcanistGoTestResultParser::parseTestResults(string, string, string) called at [<arcanist-extensions>/src/unit/engine/GoTestEngine.php:196]
  #2 GoTestEngine::resolveFuture(string, ExecFuture) called at [<arcanist-extensions>/src/unit/engine/GoTestEngine.php:57]
  #3 GoTestEngine::run() called at [<arcanist>/src/workflow/ArcanistUnitWorkflow.php:170]
  #4 ArcanistUnitWorkflow::run() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1228]
  #5 ArcanistDiffWorkflow::runUnit() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1130]
  #6 ArcanistDiffWorkflow::runLintUnit() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:365]
  #7 ArcanistDiffWorkflow::run() called at [<arcanist>/scripts/arcanist.php:419]
<<< [0] (+6,108) <exec> 6,108,182 us

What happen for this? Please give me advice.

Thanks.