nerdctl-stub: Allow positional arguments mixed with flags

[mook-as]

Sometimes it would be convenient for the user to mix positional arguments with flags, e.g. nerdctl build --tag foo . --file Containerfile.custom. Support this case by parsing all flags, then dumping all positional arguments later. This can only work if no command contains both positional arguments as well as subcommands (so that we can reliably detect them); add a case in the help output parser to check this.

This also adds a yarn generate:nerdctl-stub --verbose that gets passed to the generator so it is easier to see what it is doing.

Fixes #8190

[jandubois]

It looks like this is more complicated than I expected:

C:\Users\SUSE\build>nerdctl run busybox sh -c "echo Hello world"
2025/03/05 15:51:32 Error parsing arguments: command "container run" does not support option -c

The command runs, but the incorrect error message is not really acceptable.

Maybe there is a rule where you can't have additional [flags] if the command ends with optional arguments:

Usage: nerdctl run [flags] IMAGE [COMMAND] [ARG...]

But if you have only mandatory positional arguments, then they can be followed by more flags:

Usage: nerdctl build [flags] PATH

I haven't checked if that rule would hold everywhere, and it seems kind of too magical anyways. Unfortunately argument handling in nerdctl seems rather irregular.

[mook-as]

I think we need to look for COMMAND followed by (possibly after some distance) .... This includes:

time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[compose exec]" type=arguments usage=" NERDCTL COMPOSE EXEC [FLAGS] SERVICE COMMAND [ARGS...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[compose run]" type=arguments usage=" NERDCTL COMPOSE RUN [FLAGS] SERVICE [COMMAND] [ARGS...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[container create]" type=positional usage=" NERDCTL CONTAINER CREATE [FLAGS] IMAGE [COMMAND] [ARG...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[container exec]" type=positional usage=" NERDCTL CONTAINER EXEC [FLAGS] CONTAINER COMMAND [ARG...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[container run]" type=positional usage=" NERDCTL CONTAINER RUN [FLAGS] IMAGE [COMMAND] [ARG...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[create]" type=positional usage=" NERDCTL CREATE [FLAGS] IMAGE [COMMAND] [ARG...]"
time="2025-03-05T16:36:26-08:00" level=trace msg="building subcommand" args="[exec]" type=positional usage=" NERDCTL EXEC [FLAGS] CONTAINER COMMAND [ARG...]"
time="2025-03-05T16:36:27-08:00" level=trace msg="building subcommand" args="[run]" type=positional usage=" NERDCTL RUN [FLAGS] IMAGE [COMMAND] [ARG...]"

Note the annoying [args...] vs [arg...].

Just looking for ... finds you things like

time="2025-03-05T16:34:51-08:00" level=trace msg="building subcommand" args="[compose build]" type=positional usage=" NERDCTL COMPOSE BUILD [FLAGS] [SERVICE...]"
time="2025-03-05T16:34:52-08:00" level=trace msg="building subcommand" args="[container inspect]" type=positional usage=" NERDCTL CONTAINER INSPECT [FLAGS] CONTAINER [CONTAINER, ...]"
time="2025-03-05T16:38:05-08:00" level=trace msg="building subcommand" args="[image convert]" type=positional usage=" NERDCTL IMAGE CONVERT [FLAGS] <SOURCE_REF> <TARGET_REF>..."
time="2025-03-05T16:38:05-08:00" level=trace msg="building subcommand" args="[image inspect]" type=positional usage=" NERDCTL IMAGE INSPECT [FLAGS] IMAGE [IMAGE...]"
time="2025-03-05T16:38:05-08:00" level=trace msg="building subcommand" args="[kill]" type=positional usage=" NERDCTL KILL [FLAGS] CONTAINER [CONTAINER, ...]"
time="2025-03-05T16:38:05-08:00" level=trace msg="building subcommand" args="[namespace remove]" type=positional usage=" NERDCTL NAMESPACE REMOVE [FLAGS] NAMESPACE [NAMESPACE...]"
time="2025-03-05T16:38:06-08:00" level=trace msg="building subcommand" args="[volume inspect]" type=positional usage=" NERDCTL VOLUME INSPECT [FLAGS] VOLUME [VOLUME...]"

[jandubois]

I've rebased this PR on latest main. I was testing the CI build, including running BATS, and essentially all tests involving RDX were failing. I want to have a recent CI build before digging in deeper.

[jandubois]

Thanks, LGTM