Snap revert CLI UX discussion

snapd
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1

No way to list reverted snaps

If one has reverted a snap there is no way to list which snaps are being held at a particular revision.

Eg snap refresh --list states All snaps up to date., I was expecting this to list snaps that are being held. Or for there to be another command to list held snaps. Currently the only place I can find out if a snap is being held in the CLI is to run snap info <snap> and compare the version numbers.

Suggestion: in the output of snap refresh --list have a section listing the snaps that are being held.

No documentation of how to revert a reverted snap

If one has reverted a snap to a previous version, but then wants to revert their revert it is not obvious how this can be done. snap revert --help does not provide any information on how to reverse the command. If one runs snap refresh you get All snaps up to date. (as stated above) which doesnā€™t help. One currently has to guess that running snap refresh <snap> or snap refresh --revision=N <snap> will override the revert.

Suggestion: in the output of snap revert --help document how one can revert performing a revert on a snap (and potentially add this to snap refresh --help)

cc @Wimpress

1 Like
2

Having refresh --list mention reverted snaps doesnā€™t make sense to me: itā€™s a list of things that are going to be refreshed, and those snaps are not going to be refreshed.

An explicit snap refresh of a package is the easiest way to ā€œundoā€ a reversion:

~$ snap list --all word-salad
Name        Version  Rev  Tracking  Publisher  Notes
word-salad  0.1      7    edge      popey      disabled
word-salad  0.1      20   edge      popey      -
~$ snap revert word-salad
word-salad reverted to 0.1
Channel edge for word-salad is closed; temporarily forwarding to stable.
~$ snap list --all word-salad
Name        Version  Rev  Tracking  Publisher  Notes
word-salad  0.1      7    edge      popey      -
word-salad  0.1      20   edge      popey      disabled
~$ snap refresh word-salad
word-salad (edge) 0.1 from Alan Pope šŸ§ (popey) refreshed
~$ snap list --all word-salad
Name        Version  Rev  Tracking  Publisher  Notes
word-salad  0.1      7    edge      popey      disabled
word-salad  0.1      20   edge      popey      -

the snap revert help should mention this, yes.

3

OK, I agree that the list in refresh --list is for ones that are going to be refreshed. So what about elsewhere ? Such as a snap held command or snap list --held or snap revert --held or something ? As at the moment it really isnā€™t obvious what is being held. (something like apt-mark showhold could be useful :slight_smile: )

4

maybe we can add it to the Notes column of the regular list, if thereā€™s a sane way of exposing it in the API. The problem is that when you revert a snap all we do is write down that youā€™ve blacklisted a revision; we donā€™t know that there isnā€™t something newer (already installed, even).

@pedronis, WDYT?

5

Thanks for posting this @ahayzen. For context, this was a question raised during the recent Snapcraft live stream.

@degville Any chance you can add some documentation around reverting and refreshing from a reversion?

6

Good idea, yes. Iā€™ll try to prioritise this as I agree it absolutely needs some clarification. Thanks for letting me know.

7

Thereā€™s a related/unrelated issue to this:

  • so far we donā€™t mark as blocked kernel/core revisions for which the rollback mechanism triggered. Given they are not really installed in the end, the blocked list mechanism we have wouldnā€™t work.

If we implement that then I think it would be clearer how the API should expose ā€œblockedā€ revisions, then both snap info --verbose and snap list could do something with that.