TestOverlayView: snapshot_test.go:713: expected 1 mount option but got 2

[jas4711]

Hi! We got a report that 0.14.3 fails with a go test error like this:

=== RUN   TestOverlayView
    snapshot_test.go:713: expected 1 mount option but got 2
--- FAIL: TestOverlayView (0.01s)

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1092527
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1072067

It seems to happen when building on systems that have different kind of /tmp mount points and/or file systems.

Do you have any ideas? Do the test make some assumption about how /tmp mount points looks like?

Thanks,
Simon

[influentcoder]

It’s likely that this issue occurs because the tests are running in an unshare backend, and TMPDIR points to a non-tmpfs filesystem.

If you take a look here and here, you'll see that we set the userxattr option on the snapshotter when running inside a user namespace.

As a result, an additional mount option is added here.

In the test, we could arguably improve the check to account for this case - if running inside a user namespace and TMPDIR is not backed by tmpfs, we should expect two mount options instead of one.

Here's how I can reproduce the failure (in my case, /var/tmp is an ext4 file system):

$ unshare --user --map-root-user bash -c "TMPDIR=/var/tmp go test ./snapshot -run '^TestOverlayView$'"
--- FAIL: TestOverlayView (0.01s)
    snapshot_test.go:713: expected 1 mount option but got 2
FAIL
FAIL    github.com/containerd/stargz-snapshotter/snapshot       0.016s
FAIL