docker service ls/ps is not truncating digests anymore

[nishanttotla]

Here's an example from (more or less) master:

$ docker service create --name atest alpine sleep 1000
dhbc2sl1p79s95eqj9ps8chrk
Since --detach=false was not specified, tasks will be created in the background.
In a future release, --detach=false will become the default.

$ docker service ls
ID                  NAME                MODE                REPLICAS            IMAGE                                                                                              PORTS
dhbc2sl1p79s        atest               replicated          1/1                 docker.io/library/alpine@sha256:c0537ff6a5218ef531ece93d4984efc99bbf3f7497c0a7726c88e2bb7584dc96

$ docker service ps atest
ID                  NAME                IMAGE                                                                                              NODE                DESIRED STATE       CURRENT STATE           ERROR               PORTS
oibpq5yjwda8        atest.1             docker.io/library/alpine@sha256:c0537ff6a5218ef531ece93d4984efc99bbf3f7497c0a7726c88e2bb7584dc96   7766acd77ab4        Running             Running 9 seconds ago
root@7766acd77ab4:/go/src/github.com/docker/docker#

This was implemented in moby/moby#28539. I think this is a regression, possibly related to distribution/distribution#2142

cc @dmcgowan

[dmcgowan]

Possibly related, we added a FamiliarString for outputting the reference as a string as expected by the docker cli.

[aaronlehmann]

Why does the reference end up without a tag? That seems like the real bug to me. I would have expect it to be alpine:latest@sha256:c0537ff6a5218ef531ece93d4984efc99bbf3f7497c0a7726c88e2bb7584dc96, and I believe it used to end up this way.

[nishanttotla]

@aaronlehmann I'll open a PR to make sure that there is a default tag.

[nishanttotla]

Fixing this in moby/moby#33279

[nishanttotla]

To actually fix this issue, we do also need to revendor docker/docker into docker/cli, to bring in the changes from moby/moby#33279. Should I open a vendor PR, or is there a different procedure for cherry picking?