Inconsistent behavior with --nocapture

[michaelbeaumont]

cargo test -- --nocapture runs all my tests and I see all the stdout as it comes.
cargo test mod::test_name -- --nocapture runs mod::test_name but still captures all the output.
I don't think this is intended behavior.

I assume it has something to do with passing parameters using -- in general but I have no idea.

I'm using the nightly version of cargo installed with rustup.sh

[alexcrichton]

cc @BurntSushi, I think we may be doing something wrong with docopt here, and I'm curious to get your thoughts on this. As an example, for this program:

extern crate docopt;                                
use docopt::Docopt;                                 

static USAGE: &'static str = "                      
Usage:                                              
    foo test [options] [--] [<args>...]             

Options:                                            
    -h, --help              Print this message      
";                                                  

fn main() {                                         
    let args = Docopt::new(USAGE).unwrap()          
                      .parse()                      
                      .unwrap_or_else(|e| e.exit());
    println!("{:?}", args);                         
}                                                   

I get the following invocations.

$ ./target/wut test a -- -b
-- => Switch(false)
-h, --help => Switch(false)
<args> => List(["a", "--", "-b"])
test => Switch(true)
$ ./target/wut test -- -a
-- => Switch(true)
-h, --help => Switch(false)
<args> => List(["-a"])
test => Switch(true)
$ ./target/wut test a -b
Unknown flag: '-b'

Usage:
    foo test [options] [--] [<args>...]

The bug here is that cargo test foo -- --nocapture causes Cargo to pass down foo -- --nocapture as arguments to the test binary, and the test binary doesn't like the -- before the --nocapture. Is it a bug that docopt doesn't strip the -- argument?

[BurntSushi]

@alexcrichton Yeah, that does seem like a bug. I think I have a fix in docopt/docopt.rs@b90c40d, where I just strip the -- from the argv. I added your test cases as a regression test. :-)

[alexcrichton]

Oh awesome, thanks @BurntSushi!

[alexcrichton]

I think this was fixed in a recent update of docopt, but feel free to reopen if it still reproduces!