Error when interacting with differentials: "Testing for capability "interact" on an object ("DifferentialRevision") which does not support that capability."

Observed Behavior:
After updating our phabricator version to the versions seen below (we perform weekly updates), we receive the following error when attempting to view, abandon, or update differentials created before the update via the web UI:

Testing for capability "interact" on an object ("DifferentialRevision") which does not support that capability.

When attempting to arc diff --update --trace via the command line (with verbosity), we receive the following error:

[2019-05-28 14:57:13] EXCEPTION: (ConduitClientException) ERR-CONDUIT-CORE: Testing for capability "interact" on an object ("DifferentialRevision") which does not support that capability. at [<phutil>/src/conduit/ConduitFuture.php:58]
arcanist(), phutil()
  #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 [<phutil>/src/conduit/ConduitClient.php:64]
  #3 ConduitClient::callMethodSynchronous(string, array) called at [<arcanist>/src/workflow/ArcanistDiffWorkflow.php:574]
  #4 ArcanistDiffWorkflow::run() called at [<arcanist>/scripts/arcanist.php:394]

New differentials are able to be viewed, updated, interacted with, etc. as normal. We are seeing this behavior across multiple repositories.

Expected Behavior:
Allowing to view, modify, update, abandon, etc. existing differentials without error.

Phabricator Version:

phabricator ce6fc5be9092fd5989653ecaba53014869849b7a (Thu, May 23)
arcanist 7329bc7c32b995a7dce0319723857cbdf4f95a91 (Thu, May 23)
phutil 86ee6e90797c77ff871e7efa711d70bf80877529 (Mon, May 27)
php 5.5.9-1ubuntu4.29
diff 3.3 at /usr/bin/diff
git 1.9.1 at /usr/bin/git
hg Not Available
pygmentize 1.6 at /usr/bin/pygmentize
svn 1.8.8 at /usr/bin/svn

Reproduction Steps:
Likely recreatable using the versions we have above - we aren’t making any specific modifications to how phabricator runs. Let me know if more information is needed to recreate what we are seeing.

This should now be fixed in master by

(If you’re preforming weekly updates, you may want to track the stable branch rather than master.)

Thanks, looks like that fixed it. Are you aware if switching from master to stable could potentially cause any issues (assuming it would downgrade)?

Right now, master and stable are the same, since I promoted master to stable after landing the change in D20558. So you can move forward to stable from any state where the “interact” issue was still broken.

If you don’t get around to updating for a while but still want to switch, just wait for the next stable (see to promote and then you can upgrade forward into it.

Awesome, thanks! Unsure of how bug reports are handled here, but you can close/do whatever you need to with my report.