Variable interpolation with missing value not handled properly

[Victoremepunto]

Describe the bug

The variable interpolation does not work properly and sends a stack trace when parsing a template that has a variable using the construction: ${VARIABLE:?err}

The variable interpolation as described in and also here confirms this should be a valid construction, and this does in fact work in the latest version of docker-compose but it sends a stack trace when tested on podman-compose

please try to reproduce the bug in latest devel branch: This has been tested in both the latest stable release and in the current devel version (at the time, devel version is podman-compose version 1.0.7)

To Reproduce
Steps to reproduce the behavior:

1. have a compose template that uses interpolation with missing values. I used:

#compose.yml 
services:
  foo:
    image: ${FOO:?}

2. run a command that needs to interact with the template like: podman-compose -f compose.yml ps or simply podman-compose ps if your template is named "compose.yml"

please use minimal reproducible example for example give me a small busybox-based compose yaml

Expected behavior
docker-compose handles the error and displays a message appropriately, podman-compose should behave similarly:

$ docker-compose ps
ERROR: Missing mandatory value for "image" option interpolating ${FOO:?} in service "foo": FOO
$ echo $?
1

Actual behavior
podman-compose yields an exception and a stack trace

Output

$ podman-compose version
podman-compose version 1.0.7
podman version 4.9.3

$ podman-compose -f compose.yml ps
Traceback (most recent call last):
  File "/tmp/foo/.venv/bin/podman-compose", line 8, in <module>
    sys.exit(main())
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 3224, in main
    asyncio.run(async_main())
  File "/usr/lib64/python3.9/asyncio/runners.py", line 44, in run
    return loop.run_until_complete(main)
  File "/usr/lib64/python3.9/asyncio/base_events.py", line 647, in run_until_complete
    return future.result()
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 3220, in async_main
    await podman_compose.run()
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 1548, in run
    self._parse_compose_file()
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 1634, in _parse_compose_file
    content = rec_subs(content, self.environ)
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in rec_subs
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in <dictcomp>
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in rec_subs
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in <dictcomp>
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in rec_subs
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 266, in <dictcomp>
    value = {k: rec_subs(v, subs_dict) for k, v in value.items()}
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 282, in rec_subs
    value = var_re.sub(convert, value)
  File "/tmp/foo/.venv/lib64/python3.9/site-packages/podman_compose.py", line 279, in convert
    raise RuntimeError(m.group("err"))
RuntimeError

Environment:

• OS: Linux (Fedora 39)
• podman version: 4.9.3
• podman compose version: d704622

Additional context

N/A