Conduit method `maniphest.edit` does not recognize user IDs in the `owner` field


Observed Behavior:
Conduit method maniphest.edit does not recognize user IDs in the owner field. The only values recognized are null or the user PHID. I remember this working with user IDs in older versions (circa December 2017) but now is no longer working and the call returns the following error:

ERR-CONDUIT-CORE: Validation errors:
  - User "rencris" is not a valid user.

This is inconsistent with other fields such as subscriber.set, where user IDs work fine.

I’ve checked Conduit documentation for maniphest.edit and it declares the owner transaction as phid|null. Shouldn’t this be user|null instead?

Expected Behavior:
Users IDs should be accepted in owner transactions.

Phabricator Version:
phabricator = 9bfe558587aa55d8f0cf037640e3cfee6d642593 (Wed, Nov 28)
arcanist = 3534d2baca4bf6dcdac46c49164bf5ba3a6660ad (Thu, Nov 8)
phutil = 35d0ec2dfa595fd77410b67032e3e4262d170b6d (Wed, Nov 21)

Reproduction Steps:

  1. Calling maniphest.edit to reassign a task, with a user ID instead of PHID.