Misleading error message when trying to install unconfined snaps from the edge channel

[Simon Fels]

When I try to install the TPM snap from the edge channel I get the following output:

$ snap install tpm --channel=edge

error: cannot perform the following tasks:
- Download snap "tpm" from channel "edge" (snap not found)

The mistake here is that I forgot --devmode as the snap is published with "confinement: devmode" but the error message is misleading here. For the filtering (channel==edge && confinement==struct) its ok to say "snap not found" but the user doesn't know he did wrong. We should extend this and say that he may want to add --devmode to install the snap if its only provided with "confinement: devmode".

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Mark Shuttleworth (sabdfl)]

May I suggest:

  $ snap install hotcakes --beta
  hotcakes is not fully confined, please acknowledge with --devmode.

... unless we already had language for this in the design document.

Mark