support volume mapping into the home of a container

[maurerle]

It is supported in docker compose to have a volume mapping like /foo:~/data which should also be supported by podman compose.

This PR allows using this too.

[p12tic]

@maurerle Thanks for the PR. Is tilde volume mapping specified in the compose spec? I couldn't find it.

[p12tic]

Thanks for the PR, it looks good.

This will need unit tests for the parse_short_mount() function. But before spending time on these let's wait for me to understand what part of compose spec or undocumented docker compose behavior we are dealing with.

[maurerle]

I think that this is not documented here:
https://github.com/compose-spec/compose-spec/blob/master/07-volumes.md

It just says that the destination can be a part inside the docker container - so any valid unix path would be fine, including those starting with a tilde ~
If it does not start with an absolute path - say plain data, docker compose says invalid mount path: 'data' mount path must be absolute - so ~ is interpreted as a valid absolute path..

[p12tic]

OK, replicating undocumented behavior is fine. I was just concerned that this is documented in the spec but I can't find it.

[maurerle]

I don't know what happened but somehow this does not work with docker compose either.. ~/data:rw': invalid mount config for type "bind": invalid mount path: '~/data' mount path must be absolute
Weird - problem some wrong assumptions i had when testing before..
Sorry for that.