Feature: manifest create --amend or --replace with non-list

[c-kruse]

Feature request

When I have an image in local storage (built or pulled as a regular image) it is cumbersome to then create a manifest with that name. I would prefer have options on manifest create to either convert the existing non-list image into a manifest or to untag the conflicting image (list or non-list alike?)

ex:

$ buildah build -t myrepo.local/test:v1 .
...
Writing manifest to image destination
--> bf88f9442771
Successfully tagged myrepo.local/test:v1
bf88f9442771cce6d2c1522311db10252c7f102f216cc4e49ecdd77b596f6bef
$ buildah manifest create myrepo.local/test:v1
Error: image name "myrepo.local/test:v1" is already associated with image "bf88f9442771cce6d2c1522311db10252c7f102f216cc4e49ecdd77b596f6bef": that name is already in use
$ buildah tag myrepo.local/test:v1 myrepo.local/test:tmp-v1
$ buildah rmi myrepo.local/test:v1
untagged: myrepo.local/test:v1
$ buildah manifest create myrepo.local/test:v1 myrepo.local/test:tmp-v1
d2091e4afbbdd96d55acab5ef15fe54e25a8b271782276f31dd010dfb41945f3

Suggested approach

Extend the buildah manifest create (and podman manifest create) command with two flags for handling name conflicts with non-list images:

• Expand --amend to convert a non-list image with the desired manifest name into a list.
• Add --replace to remove an image with the desired name before creating the manifest.

Context

I started here: containers/podman#24537

Prior relevant work: containers/common#2091

[c-kruse]

I would be happy to spend some time contributing on this. Wanted to get agreement on whether or not this is a problem that should be addressed and and if so, is this proposal the right way forward.

[Honny1]

Go ahead, I think new flags would be useful. Just note that it might be good to link to or explain what a non-list image is in the documentation.