When using Buildkite through a build plan the correct user identity information is not provided to Buildkite. This results in every build showing up as being done by the creator of the Buildkite token, instead of the author of the differential revision.

STR:

• Create a API token in Buildkite.
• Create a build plan which runs code against Buildkite and uses the token we created.
• Create a differential revision, triggering the build plan and building with Buildkite.
• Visit the external Buildkite page.

Expected Result:

• The author information displayed in Buildkite will show the author of the Phabricator differential revision.

Actual Result:

• The author information shows the account information of the user who created the token.

Versions:
phabricator 061375fde6525ea3e6eb701ddc570c5a422d7ffc (Apr 4 2017)
arcanist 60aaee0ed3f5a1e4384ac7d7f2efd2c64cecbe44 (Mar 24 2017)
phutil f568eb7b9542259cd3c0dcb3405cc9a83c90a2f5 (Apr 3 2017)