“Action With No Effect” when removing auto-assign


Observed Behavior:
When closing an unassigned task, Phabricator auto-assigns it to the closing user (unless closing to one of those states with claim=false in the maniphest.statuses config). If I want not to claim the task in a specific case, I can add two actions: Change Status (the preview below shows claimed this task + closed this task), and Assign/Claim and remove myself, leaving the edit box empty (the preview below shows only closed this task). Everything works correctly (the task will get closed without me claiming it), however, Phabricator displays a warning:

Action With No Effect

One of your actions has no effect:

The task already has the selected owner.

Apply remaining actions?

Which is wrong; it is true the task already has the selected owner (nobody), but removing the action would change the result.

Expected Behavior:
Phabricator should not display the warning. (Otherwise, everything works correctly as is.)

Phabricator Version:
Reproduced on a fresh Test Phacility installation:

3f2419eebb6114cd8b85d8763289efdb8c427125 (Sat, Feb 24) (branched from 4c7370a1a3b0b59f4ce6fc731a59b637f75c0ed2 on origin)
8fe1d7701e5daa3b7c8d96847fa335c0fbf66816 (Fri, Feb 16) (branched from be1dd7e2ba230d77f894637fdcbc7d5a47dc7082 on origin)
03e5605b42e4e5ee721a282408f9dfc75179f671 (Sat, Feb 24) (branched from a0de1601cb60f79c805582bdc5be03ac7058fb41 on origin)
c937d905b63e2d1a0177aac11243e32498d59ea6 (Fri, Feb 9)
92fb89c30b06e425d34b01e7fea34a654f2c978f (Jan 27 2018) (branched from edd96db6a371bfa8ad5da78480c4ec24edb8efe7 on origin)

Reproduction Steps:

  1. Create an example Maniphest task (not assigned to anyone).
  2. In the task detail, choose Add Action…, Change Status, choose Resolved. (The preview below will show [You] claimed this task. and [You] closed this task as Resolved.)
  3. Choose Add Action…, Assign / Claim, click on [x] next to your name to remove yourself from the assignment box. (The preview below will change to show only [You] closed this task as Resolved.)
  4. Click Set Sail to Adventure.
  5. The Action With No Effect warning dialog will appear.