`run` doesn't pass empty arguments

[brson]

Source

rustup run stable cargo build --verbose --no-default-features --features ""

Expected argument for flag '--features' but reached end of arguments.

[brson]

This is probably a bug in clap or me not understanding clap. The code is pretty straightforward. values_of("command") is supposed to return multiple arguments but doesn't return the trailing empty argument. cc @kbknapp does this look familiar to you?

[brson]

"command" is defined as Arg::with_name("command").required(true).multiple(true))

[kbknapp]

@brson I think that's a docopt error message, or at least it's not one from clap. The error clap would have given in the same scenario (expecting an argument value but not getting one) would be:

$ fake-rs --features
error: The argument '--features <feature>...' requires a value but none was supplied

USAGE:
    fake-rs [FLAGS] --features <feature>...

For more information try --help

I also just tested it with the empty string: --features "" which doesn't give an error. Empty values are allowed by default.

Side note, you can force it to be an error with the Arg::empty_values(false) if that's desired.

[kbknapp]

@brson Thinking about it, I think it's because those arguments are being passed to cargo, which explains the error message.

[brson]

Yes it's because the error came from cargo. I'll keep looking into it. Thanks

[kbknapp]

@brson Ah ok, I misunderstood how it was running, I wasn't thinking the entire stable cargo build --verbose --no-default-features --features "" was being passed. This may in fact be a bug, let me look into it a little deeper I'll get back.

[brson]

@kbknapp here's a test case https://gist.github.com/brson/2e4a020b220500d9b2d24e4c2faef29c

[kbknapp]

Thanks! Checking it out now.

[kbknapp]

Just put in a PR to fix this!

Edit: I'll post back here once the new version is on crates.io (should be ~30 mins)

[kbknapp]

v2.2.4 is on crates.io

[brson]

\o/ @kbknapp Thanks for the quick update! I'm pulling it in now.