Stack trace shared by @amit from Q55 while importing a Mercurial repository:
[08-May-2023 14:01:03 UTC] [2023-05-08 14:01:03] EXCEPTION: (PhutilProxyException) Error while executing Task ID 180186. {>} (RuntimeException) strlen(): Passing null to parameter #1 ($string) of type string is deprecated at [<arcanist>/src/error/PhutilErrorHandler.php:261]
[08-May-2023 14:01:03 UTC] arcanist(head=stable, ref.master=a1ee2ab93158, ref.stable=d47289622650), phorge(head=stable, ref.master=58fbf64a2786, ref.stable=d74e9d825a2c)
[08-May-2023 14:01:03 UTC] #0 <#2> PhutilErrorHandler::handleError(integer, string, string, integer) called at [<phorge>/src/applications/search/engine/PhabricatorApplicationSearchEngine.php:1140]
[08-May-2023 14:01:03 UTC] #1 <#2> PhabricatorApplicationSearchEngine::buildConduitResponse(ConduitAPIRequest, DiffusionInternalCommitSearchConduitAPIMethod) called at [<phorge>/src/applications/search/engine/PhabricatorSearchEngineAPIMethod.php:52]
[08-May-2023 14:01:03 UTC] #2 <#2> PhabricatorSearchEngineAPIMethod::execute(ConduitAPIRequest) called at [<phorge>/src/applications/conduit/method/ConduitAPIMethod.php:156]
[08-May-2023 14:01:03 UTC] #3 <#2> ConduitAPIMethod::executeMethod(ConduitAPIRequest) called at [<phorge>/src/applications/conduit/call/ConduitCall.php:131]
[08-May-2023 14:01:03 UTC] #4 <#2> ConduitCall::executeMethod() called at [<phorge>/src/applications/conduit/call/ConduitCall.php:81]
[08-May-2023 14:01:03 UTC] #5 <#2> ConduitCall::execute() called at [<arcanist>/src/future/MethodCallFuture.php:30]
[08-May-2023 14:01:03 UTC] #6 <#2> MethodCallFuture::isReady() called at [<arcanist>/src/future/Future.php:63]
[08-May-2023 14:01:03 UTC] #7 <#2> Future::updateFuture() called at [<arcanist>/src/future/Future.php:159]
[08-May-2023 14:01:03 UTC] #8 <#2> Future::start() called at [<arcanist>/src/future/FutureIterator.php:403]
[08-May-2023 14:01:03 UTC] #9 <#2> FutureIterator::moveFutureToWork(integer) called at [<arcanist>/src/future/FutureIterator.php:374]
[08-May-2023 14:01:03 UTC] #10 <#2> FutureIterator::updateWorkingSet() called at [<arcanist>/src/future/FutureIterator.php:206]
[08-May-2023 14:01:03 UTC] #11 <#2> FutureIterator::next() called at [<arcanist>/src/future/FutureIterator.php:190]
[08-May-2023 14:01:03 UTC] #12 <#2> FutureIterator::rewind()
[08-May-2023 14:01:03 UTC] #13 <#2> iterator_to_array(FutureIterator) called at [<arcanist>/src/future/FutureIterator.php:84]
[08-May-2023 14:01:03 UTC] #14 <#2> FutureIterator::resolveAll() called at [<arcanist>/src/future/Future.php:47]
[08-May-2023 14:01:03 UTC] #15 <#2> Future::resolve() called at [<phorge>/src/applications/repository/storage/PhabricatorRepositoryCommit.php:549]
[08-May-2023 14:01:03 UTC] #16 <#2> PhabricatorRepositoryCommit::newCommitRef(PhabricatorUser) called at [<phorge>/src/applications/repository/worker/commitmessageparser/PhabricatorRepositoryCommitMessageParserWorker.php:19]
[08-May-2023 14:01:03 UTC] #17 <#2> PhabricatorRepositoryCommitMessageParserWorker::parseCommit(PhabricatorRepository, PhabricatorRepositoryCommit) called at [<phorge>/src/applications/repository/worker/PhabricatorRepositoryCommitParserWorker.php:72]
[08-May-2023 14:01:03 UTC] #18 <#2> PhabricatorRepositoryCommitParserWorker::doWork() called at [<phorge>/src/infrastructure/daemon/workers/PhabricatorWorker.php:124]
[08-May-2023 14:01:03 UTC] #19 <#2> PhabricatorWorker::executeTask() called at [<phorge>/src/infrastructure/daemon/workers/storage/PhabricatorWorkerActiveTask.php:160]
[08-May-2023 14:01:03 UTC] #20 <#2> PhabricatorWorkerActiveTask::executeTask() called at [<phorge>/src/infrastructure/daemon/workers/PhabricatorTaskmasterDaemon.php:22]
[08-May-2023 14:01:03 UTC] #21 PhabricatorTaskmasterDaemon::run() called at [<phorge>/src/infrastructure/daemon/PhutilDaemon.php:219]
[08-May-2023 14:01:03 UTC] #22 PhutilDaemon::execute() called at [<phorge>/scripts/daemon/exec/exec_daemon.php:131]Marking as Diffusion since this bug was raised by the Diffusion homepage, but very probably the solution is not strictly related to that.