Two users have reported this issue to me today. They receive the following error when attempting to create a differential revision:
[2016-05-17 23:57:08] EXCEPTION: (ConduitClientException) ERR-CONDUIT-CORE: Expected a scalar or null for %Ls conversion. Query: user.phid IN (%Ls) at [<phutil>/src/conduit/ConduitFuture.php:58] arcanist(head=master, ref.master=2234c8cacc21), phutil(head=master, ref.master=b25e0477b280) #0 ConduitFuture::didReceiveResult(array) called at [<phutil>/src/future/FutureProxy.php:58] #1 FutureProxy::getResult() called at [<phutil>/src/future/FutureProxy.php:35] #2 FutureProxy::resolve() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1832] #3 ArcanistDiffWorkflow::validateCommitMessage(ArcanistDifferentialCommitMessage) called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1712] #4 Arcanis tDiffWorkflow::getCommitMessageFromUser() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:1517] #5 ArcanistDiffWorkflow::buildCommitMessage() called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:469] #6 ArcanistDiffWorkflow::run() called at [<arcanist>/scripts/arcanist.php:392]
Server-side, I see this in the logs:
[18-May-2016 09:58:51 Australia/Sydney] [2016-05-18 09:58:51] EXCEPTION: (ConduitException) API Method "user.query" does not define these parameters: 'user.phid'. at [<phabricator>/src/applications/conduit/call/ConduitCall.php:37] [18-May-2016 09:58:51 Australia/Sydney] arcanist(head=master, ref.master=2234c8cacc21), phabricator(head=master, ref.master=de1a30efc740, custom=1), phlab(head=master, ref.master=84b62e6917ec), phutil(head=master, ref.master=b25e0477b280) [18-May-2016 09:58:51 Australia/Sydney] #0 <#2> ConduitCall::__construct(string, array) called at [<phabricator>/src/applications/conduit/controller/PhabricatorConduitAPIController.php:30] [18-May-2016 09:58:51 Australia/Sydney] #1 phlog(ConduitException) called at [<phabricator>/src/applications/conduit/controller/PhabricatorConduitAPIController.php:101] [18-May-2016 09:58:51 Australia/Sydney] #2 PhabricatorConduitAPIController::handleRequest(AphrontRequest) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:237] [18-May-2016 09:58:51 Australia/Sydney] #3 AphrontApplicationConfiguration::processRequest(AphrontRequest, PhutilDeferredLog, AphrontPHPHTTPSink, MultimeterControl) called at [<phabricator>/src/aphront/configuration/AphrontApplicationConfiguration.php:149] [18-May-2016 09:58:51 Australia/Sydney] #4 AphrontApplicationConfiguration::runHTTPRequest(AphrontPHPHTTPSink) called at [<phabricator>/webroot/index.php:17]