Inconsistent report of branch HEAD position

[zanerock]

There seems to be a problem with github giving consistent reports about the branch head:

Notice the 'last commit'. But if I fetch that repo locally and then check the origin/task-796... head:

git rev-parse origin/topics-796-e221f943-5e22-44d1-9f65-c9fd1e197c27
fac79ffea39ed8dcdec3839511bc17e983d0bc15

The log (edited for brevity) as viewed from the local git cli is the same for both the local and remote branch (i.e.: git log task-796... and git log origin/task-796...

commit fac79ffea39ed8dcdec3839511bc17e983d0bc15
...
    added bar

commit 1120bd6ddbc0fb295e4339ea49c0d98bd5855535
...
    Initialized conveyor-workflow repo with README.repo file.

In my testing, the error happens about 1 in 20 to 1 in 60. It may have to do with github getting a PR request very quickly after the branch is pushed. (BTW, I'm not using hub myself). For now, when I detect the (possible) situation, I delete and re-add the branch. There appear to be times when the problem puts up with much greater consistency for a number of hours, then it becomes consistently rarer for a period. This may be an observation bias, but it did appear rather marked.

[zanerock]

I'm not 100% sure about this (there may be a flaw in the reporting) but it appears that the PR comes back with a HTTP status of 422 maybe 50% of the time, and a 200 status the rest. The body is always the same:

{"message":"Validation Failed","documentation_url":"https://developer.github.com/v3/pulls/#create-a-pull-request","errors":[{"resource":"PullRequest","code":"custom","message":"No commits between DogFoodSoftware:master and DogFoodSoftware:topics-189-1e72315f-7d4f-4ca6-8022-ff29dd0929b1"}]}

This appears to be related to this issue from hub:
mislav/hub#189

[JeffryBooher]

@zanerock I think you posted to the wrong repo. This is showing up in the https://github.com/adobe/brackets repo...

[zanerock]

Apologies.