In a YAML "compose" file, the path of the Dockerfile is often specified as a relative path to the location of the YAML "compose" file itself using the context keyword. When using docker-compose with the VSCode dev container, VSCode will first call docker-compose config to expand the relative paths to absolute paths and then use the resulting absolute paths to locate the Dockerfiles to build.
However, podman-compose config is not fully implemented. It simply prints out the YAML file verbatim without any normalization. If we use podman-compose as a replacement for docker-compose, since VSCode does not set the current directory to that of the YAML "compose" file when it tries to find the Dockerfiles, the lack of normalization causes it to fail to find them using the relative paths.
This script is a wrapper around podman-compose. It intercepts the podman-compose config command and will normalize any relative path specified with the context keyword in the YAML "compose" file. For any other commands, it simply calls the original podman-comose. It is a stopgap until pdoman-compose fully implements the config command.
To use it, we need to set it up such that both VSCode and podman compose will call this script instead of the original podman-compose.
In the Dev Container extension setting, set Dev > Containers > Docker Compose Path, set it to this script.
For rootless containers, in ~/.config/containers/containers.conf, add the following:
[engine]
compose_providers=['/path/to/this/script']
For details, see man containers.conf(5).