Viewing a diff with code coverage for some but not all files fails with strlen(null) under PHP 8.1
Stack trace:
AH01071: Got error 'PHP message: [2023-06-30 07:31:46] 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/controller/DifferentialChangesetViewController.php:454]PHP message: #1 <#2> DifferentialChangesetViewController::loadCoverage(DifferentialChangeset) called at [<phorge>/src/applications/differential/controller/DifferentialChangesetViewController.php:140]PHP message: #2 <#2> DifferentialChangesetViewController::handleRequest(AphrontRequest) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:284]PHP message: #3 phlog(RuntimeException) called at [<phorge>/src/aphront/handler/PhabricatorDefaultRequestExceptionHandler.php:41]PHP message: #4 PhabricatorDefaultRequestExceptionHandler::handleRequestThrowable(AphrontRequest, RuntimeException) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:751]PHP message: #5 AphrontApplicationConfiguration::handleThrowable(RuntimeException) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:296]PHP message: #6 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phorge>/src/aphront/configuration/AphrontApplicationConfiguration.php:204]PHP message: #7 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phorge>/webroot/index.php:35]'