In an early morning haze I mistyped a revision ID in arc patch and got an exception:
cspeck@host ~/S/p/code> arc patch 40439 --trace ARGV '/Users/cspeck/Projects/phacility/arcanist/bin/../scripts/arcanist.php' 'patch' '40439' '--trace' LOAD Loaded "phutil" from "/Users/cspeck/Projects/phacility/libphutil/src". LOAD Loaded "arcanist" from "/Users/cspeck/Projects/phacility/arcanist/src". Config: Reading user configuration file "/Users/cspeck/.arcrc"... Config: Did not find system configuration at "/etc/arcconfig". Working Copy: Reading .arcconfig from "/Users/cspeck/Source/project/code/.arcconfig". Working Copy: Path "/Users/cspeck/Source/project/code" is part of `hg` working copy "/Users/cspeck/Source/project/code". Working Copy: Project root is at "/Users/cspeck/Source/project/code". Config: Did not find local configuration at "/Users/cspeck/Source/project/code/.hg/arc/config". >>> [0] <conduit> differential.querydiffs() <bytes = 76> >>> [1] <http> https://repo.company.com/api/differential.querydiffs <<< [1] <http> 260,382 us <<< [0] <conduit> 261,379 us >>> [2] <conduit> user.whoami() <bytes = 117> >>> [3] <http> https://repo.company.com/api/user.whoami <<< [3] <http> 244,422 us <<< [2] <conduit> 244,647 us >>> [4] <conduit> differential.querydiffs() <bytes = 157> >>> [5] <http> https://repo.company.com/api/differential.querydiffs <<< [5] <http> 242,392 us <<< [4] <conduit> 242,618 us [2016-09-20 13:20:06] ERROR 2: Invalid argument supplied for foreach() at [/Users/cspeck/Projects/phacility/arcanist/src/workflow/ArcanistWorkflow.php:1200] arcanist(head=master, ref.master=9e82ef979e81), phutil(head=master, ref.master=f241706ade25) #0 ArcanistWorkflow::loadBundleFromConduit(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWorkflow.php:1189] #1 ArcanistWorkflow::loadRevisionBundleFromConduit(ConduitClient, string) called at [<arcanist>/src/workflow/ArcanistPatchWorkflow.php:384] #2 ArcanistPatchWorkflow::run() called at [<arcanist>/src/workflow/ArcanistPatchWorkflow.php:397] #3 ArcanistPatchWorkflow::run() called at [<arcanist>/scripts/arcanist.php:394] [2016-09-20 13:20:06] EXCEPTION: (InvalidArgumentException) Argument 1 passed to idx() must be of the type array, boolean given, called in /Users/cspeck/Projects/phacility/arcanist/src/workflow/ArcanistWorkflow.php on line 1207 and defined at [<phutil>/src/error/PhutilErrorHandler.php:200] arcanist(head=master, ref.master=9e82ef979e81), phutil(head=master, ref.master=f241706ade25) #0 PhutilErrorHandler::handleError(integer, string, string, integer, array) called at [<phutil>/src/utils/utils.php:36] #1 idx(boolean, string) called at [<arcanist>/src/workflow/ArcanistWorkflow.php:1207] #2 ArcanistWorkflow::loadBundleFromConduit(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWorkflow.php:1189] #3 ArcanistWorkflow::loadRevisionBundleFromConduit(ConduitClient, string) called at [<arcanist>/src/workflow/ArcanistPatchWorkflow.php:384] #4 ArcanistPatchWorkflow::run() called at [<arcanist>/src/workflow/ArcanistPatchWorkflow.php:397] #5 ArcanistPatchWorkflow::run() called at [<arcanist>/scripts/arcanist.php:394]