Unnecessary CustomCli: clap::Args bound in Cucumber::with_cli()

[yds12]

I usually use the Cucumber::with_cli method to configure both the cucumber options (such as --tags and --features) and also custom options. Is there a way to pass these configurations without using a struct that derives clap::Args?

[ilslv]

@yds12 Cucumber has a lot of configuration options, for example --tags or --features can be substituted with Cucumber::filter_run_and_exit(). Are there any specific options you are missing?

[yds12]

Thanks for the quick feedback @ilslv . In my case, it's not much about any particular option but the Cli config as a whole. The problem I have, to give more context, is that we have a complex setup with a library wrapping cucumber-rs and other binary projects that import that library. Sometimes those projects don't necessarily have clap, but they still might have their own CLI options, so we would benefit if we could pass to cucumber-rs something pretty much identical to the Cli object, but without being an instance of clap::Args. For now what we do is to build this Cli that implement clap::Args manually, but that's far from ideal and sometimes we get strange errors due to clap trying to validate this even though there's no actual CLI being parsed (when deriving clap::Args, the macro generates a lot of code, I think some validation is inserted there).

My understanding is that this is not currently possible, so this issue would be like a feature suggestion (if it fits with the project's goals). But please let me know if I am missing something.

[ilslv]

@yds12 as far as I can understand the problem is in CustomCli: clap::Args bound in Cucumber::with_cli(). I'll take a look whether we can relax this bound, but in the meantime you can implement wrapper that will implement empty clap::Args for any type:

use clap::Args;

#[derive(Args, Clone, Copy, Debug)]
#[group(skip)]
struct Empty<T: Default> {
    #[arg(skip)]
    inner: T,
}

[yds12]

Thanks @ilslv, that helps!

[ilslv]

This issue originates in clap-rs/clap#3032, so we can't easily remove CustomCli: clap::Args bound.

Theoretically we can try implementing clap::Parser manually on cli::Opts, but this would complicate code a lot and I don't even know whether this trait is stable and suitable for manual implementation. As use-case described in the issue is quite rare and working hack was found, I'm closing this issue for now.