I'm getting following notices as part of `arc which` command output:
```
[2014-11-25 11:45:49] ERROR 8: Undefined index: sourcePath at [.../arcanist/src/repository/api/ArcanistSubversionAPI.php:766]
#0 ArcanistSubversionAPI::loadWorkingCopyDifferentialRevisions(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWhichWorkflow.php:177]
#1 ArcanistWhichWorkflow::run() called at [<arcanist>/scripts/arcanist.php:338]
[2014-11-25 11:45:49] ERROR 8: Undefined index: sourcePath at [.../arcanist/src/repository/api/ArcanistSubversionAPI.php:766]
#0 ArcanistSubversionAPI::loadWorkingCopyDifferentialRevisions(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWhichWorkflow.php:177]
#1 ArcanistWhichWorkflow::run() called at [<arcanist>/scripts/arcanist.php:338]
[2014-11-25 11:45:49] ERROR 8: Undefined index: sourcePath at [.../arcanist/src/repository/api/ArcanistSubversionAPI.php:766]
#0 ArcanistSubversionAPI::loadWorkingCopyDifferentialRevisions(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWhichWorkflow.php:177]
#1 ArcanistWhichWorkflow::run() called at [<arcanist>/scripts/arcanist.php:338]
[2014-11-25 11:45:49] ERROR 8: Undefined index: sourcePath at [.../arcanist/src/repository/api/ArcanistSubversionAPI.php:766]
#0 ArcanistSubversionAPI::loadWorkingCopyDifferentialRevisions(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWhichWorkflow.php:177]
#1 ArcanistWhichWorkflow::run() called at [<arcanist>/scripts/arcanist.php:338]
[2014-11-25 11:45:49] ERROR 8: Undefined index: sourcePath at [.../arcanist/src/repository/api/ArcanistSubversionAPI.php:766]
#0 ArcanistSubversionAPI::loadWorkingCopyDifferentialRevisions(ConduitClient, array) called at [<arcanist>/src/workflow/ArcanistWhichWorkflow.php:177]
#1 ArcanistWhichWorkflow::run() called at [<arcanist>/scripts/arcanist.php:338]
```
This happens because all diffs on a particular arcanist project are created by another user (not one who is doing `arc which`). The `sourcePath` key in https://secure.phabricator.com/diffusion/P/browse/master/src/applications/differential/conduit/DifferentialQueryConduitAPIMethod.php;37d14a85b38f80e9c0c8b54ef208baffc7b910de$238 is only populated for own diffs but the https://secure.phabricator.com/diffusion/ARC/browse/master/src/repository/api/ArcanistSubversionAPI.php;b46d4ed4ad01556a9400c836dc11cd1432d1f75b$662 is aksing the `sourcePath` regardless of it's presense which triggers that notice.