snapcraft should warn of invalid name

[Olivier Tilloy]

This looks similar to bug #1589613, but I’m not sure whether I should just re-open it, so here’s a new one.
Snapcraft allows building snaps with invalid names, which are then installed but cannot be run because snap-confine complains of an invalid security tag:

$ snapcraft
"grade" property not specified: defaulting to "stable"
Preparing to pull 1foo
Pulling 1foo
Preparing to build 1foo
Building 1foo
Staging 1foo
Priming 1foo
Snapping '1foo' |
Snapped 1foo_1.0_amd64.snap
$ sudo snap install --dangerous 1foo_1.0_amd64.snap
1foo 1.0 installed
$ 1foo
security tag snap.1foo.1foo not allowed

This happens if the name of the snap starts with a number (e.g. "1foo"). The documentation for verify_security_tag(…) in snap-confine specifies that <name> must start with lowercase letter, then may contain lowercase alphanumerics and '-'.

Snapcraft should bail out early instead of generating a snap with an invalid name.

[Olivier Tilloy (osomon)]

Here is a test snapcraft.yaml file for the use case:

$ cat snapcraft.yaml
name: 1foo
version: 1.0
summary: snap with invalid name
description: a snap package with an invalid name
confinement: strict
apps:
  1foo:
    command: bin/1foo
parts:
  1foo:
    plugin: dump
    source: .
    organize:
      1foo: bin/

[Launchpad Janitor (janitor)]

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

[Carroarmato0 (carroarmato0)]

Oh, apparently a bug since last year. I'm getting the same.

I'm trying to snap a commandline tool written in Go called 12to8...

I don't think you can really expect upstream projects to all start changing their names.

[carroarmato0:~/Applications … opment/Snaps/12to8] $ 12to8
security tag snap.12to8.12to8 not allowed

[John Lenton (chipaca)]

For what it's worth, "12to8" is a valid snap name, and a valid app name. There was a bug in snapd (getting fixed right now).