Is your feature request related to a problem? Please describe.

It is possible that we have two different processes where one needs to use docker-compose and the other podman-compose but interacting with the same container socket, containers, and compose project. For example, maybe certain configuration is only available in one or the other and no single implementation covers the entire use-case.

Unfortunately, containers started by one is not visible from the other.

This is due to project-matching being done by matching the label io.podman.compose.project. Containers started by docker-compose instead carry the io.podman.compose.project. It seems to be no way to make them work together due to this.

Describe the solution you'd like

Introduce a new environment variable like COMPOSE_LABEL_NAMESPACE defaulting to io.podman. Users can then interact with projects managed by docker-compose via COMPOSE_LABEL_NAMESPACE=com.docker, or set their own namespace.

Describe alternatives you've considered
Transparently filter for both currently known namespaces. This seems to not be worth it.

Additional context