Re: on Amazon EFS (NFS): "Reference directory conflict: refs/heads/" with status code 128

On Wed, Aug 24, 2016 at 04:52:33PM -0400, Alex Nauda wrote:

Elastic File System (EFS) is Amazon's scalable filesystem product that
is exposed to the OS as an NFS mount. We're using EFS to host the
filesystem used by a Jenkins CI server. Sometimes when Jenkins tries
to git fetch, we get this error:
$ git -c core.askpass=true fetch --tags --progress
git@github.com:mediasilo/dodo.git
+refs/pull/*:refs/remotes/origin/pr/*
fatal: Reference directory conflict: refs/heads/
$ echo $? 128

Has anyone seen anything like this before? Any tips on how to troubleshoot it?

No, I haven't seen it before. That's an internal assertion in the refs
code that shouldn't ever happen. It looks like it happens when the loose
refs end up with duplicate directory entries. While a bug in git is an
obvious culprit, I wonder if it's possible that your filesystem might
expose the same name twice in one set of readdir() results.

+cc Michael, who added this assertion long ago (and since this is the
first report in all these years, it does make me suspect that the
filesystem is a critical part of reproducing).

-Peff