To add to what stub is seeing, we've also seen upgrade-charm fail with relative paths:
$ juju upgrade-charm layer-test --path=~/charms/trusty/layer-test ERROR charm or bundle URL has invalid form: "~/charms/trusty/layer-test"
$ juju upgrade-charm layer-test --path ~/charms/trusty/layer-test/ ERROR cannot upgrade "layer-test" to ""
$ juju upgrade-charm layer-test --path ~/charms/trusty/layer-test Added charm "local:trusty/layer-test-1" to the model.
To add to what stub is seeing, we've also seen upgrade-charm fail with relative paths:
$ juju upgrade-charm layer-test --path= ~/charms/ trusty/ layer-test trusty/ layer-test"
ERROR charm or bundle URL has invalid form: "~/charms/
$ juju upgrade-charm layer-test --path ~/charms/ trusty/ layer-test/
ERROR cannot upgrade "layer-test" to ""
$ juju upgrade-charm layer-test --path ~/charms/ trusty/ layer-test trusty/ layer-test- 1" to the model.
Added charm "local: