[4.0.4] Equal sign is not allowed in a command

[Dmitrii Shcherbakov]

I believe '=' used to be allowed in earlier versions of snapcraft but now it is not:

Failed to generate snap metadata: The specified command 'ovs-wrapper $SNAP/share/openvswitch/scripts/ovs-ctl --no-ovsdb-server --no-monitor --system-id=random start' defined in the app 'ovs-vswitchd' does not match the pattern expected by snapd.
The command must consist only of alphanumeric characters, spaces, and the following special characters: / . _ # : $ -

The equal sign is often used in command line arguments:

  ovs-vswitchd:
    command: ovs-wrapper $SNAP/share/openvswitch/scripts/ovs-ctl --no-ovsdb-server --no-monitor --system-id=random start
    stop-command: ovs-wrapper $SNAP/share/openvswitch/scripts/ovs-ctl --no-ovsdb-server stop
    after: [ovsdb-server]
    daemon: forking
    plugs:
      - network
      - network-bind
      - network-control
      - openvswitch-support
      - process-control
      - system-trace
      - microstack-support

[Sergio Schvezov (sergiusens)]

This is correct, one of the goals of core20 was to get rid of wrappers, to do so, we now only allow a command entry that snapd would accept. So this is essentially a snapd feature request.

[Colin Ian King (colin-king)]

Is this deprecated feature in the release notes anywhere?

[Sergio Schvezov (sergiusens)]

I added a note for when we first released this https://github.com/snapcore/snapcraft/releases/tag/3.9

And amended https://github.com/snapcore/snapcraft/releases/tag/4.0 with a Commands section.

[Zygmunt Krynicki (zyga)]

I had a look at the code and this is indeed the way the validator works. I'll discuss if allowing = would be allowed.

[Zygmunt Krynicki (zyga)]

Assigned to Samuele for design decisions.

[Lucy Llewellyn (lucyllewy)]

Also quotes are desirable, such as when trying to pass a parameter with spaces in it. (ref: https://forum.snapcraft.io/t/spaces-in-executable-path/22229/)

[Zack (zacklee)]

There seems to be another thread from 2019 with regards to the same ask: https://bugs.launchpad.net/snapcraft/+bug/1820055 which is already in Triaged status. It would be good to merge these two threads and get this moving along...