confusing schema validation error when mandatory subkey is missing

[Robert Collins]

This looks very similar to bug 813831.

Something with very similar symptoms occurred to me with clint's lxc branch:
I was missing a required lxc subkey, but the error claimed:
environments.local.type: expected 'ec2', got 'lxc'

The actual best error raised during schema validation was:
environments.local.storage-directory: required value not found

but both had path length (5) so the more specific error did not override the less specific error.

Perhaps this would be fixed by setting the path ['environments', '.', 'local', '.', 'storage-directory'] similar to how the type error path is set - e.g.

['environments', '.', 'local', '.', 'storage-directory', '.', 'existence']

[William Reade (fwereade)]

If you merge the latest trunk, and use a SelectDict instead of a OneOf in ensemble.environment.config, you should see some improvement.

[Clint Byrum (clint-fewbar)]

I think this actually was part of 813831, marking as a dupe.