When doing 'arc diff' to a Phorge server running PHP 8.1, DifferentialDiff getFieldValuesForConduit throws strlen(null) exceptions.
Stack trace:
AH01071: Got error 'PHP message: [2023-06-30 07:57:15] EXCEPTION: (RuntimeException) strlen(): Passing null to parameter #1 ($string) of type string is deprecated at [<arcanist>/src/error/PhutilErrorHandler.php:261]PHP message: arcanist(head=master, ref.master=8130241a11ac, custom=4), phorge(head=master, ref.master=7c1487e4dcfa)PHP message: #0 <#2> PhutilErrorHandler::handleError(integer, string, string, integer) called at [<phorge>/src/applications/differential/storage/DifferentialDiff.php:807]PHP message: #1 <#2> DifferentialDiff::getFieldValuesForConduit() called at [<phorge>/src/applications/conduit/query/ConduitResultSearchEngineExtension.php:29]PHP message: #2 <#2> ConduitResultSearchEngineExtension::getFieldValuesForConduit(DifferentialDiff, NULL) called at [<phorge>/src/applications/search/engine/PhabricatorApplicationSearchEngine.php:1422]PHP message: #3 <#2> PhabricatorApplicationSearchEngine::getObjectWireFieldsForConduit(DifferentialDiff, array, array) called at [<phorge>/src/applications/search/engine/PhabricatorApplicationSearchEngine.php:1250]PHP message: #4 <#2> PhabricatorApplicationSearchEngine::buildConduitResponse(ConduitAPIRequest, DifferentialDiffSearchConduitAPIMethod) called at [<phorge>/src/applications/search/engine/PhabricatorSearchEngineAPIMethod.php:52]PHP message: #5 <#2> PhabricatorSearchEngineAPIMethod::execute(ConduitAPIRequest) called at [<phorge>/src/applications/conduit/method/ConduitAPIMethod.php:156]PHP message: #6 <#2> ConduitAPIMethod::executeMethod(ConduitAPIRequest) called at [<phorge>/src/applications/conduit/call/ConduitCall.php:131]PHP message: #7 <#2> ConduitCall::executeMethod() called at [<phorge>/src/applications/conduit/call/ConduitCall.php:81]PHP message: #8 <#2> ConduitCall::execute() called at [<phorge>/src/applications/conduit/controller/PhabricatorConduitAPIController.php:83]PHP message: #9 phlog(RuntimeException) called at [<phorge>/src/applications/conduit/controller/PhabricatorConduitAPIController.php:111]PHP message: #10 PhabricatorConduitAPIController::handleRequest(AphrontRequest) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:284]PHP message: #11 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:204]PHP message: #12 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phorge>/webroot/index.php:35]'