nightly 2018/03/19: change of position of arguments passed to cargo subcommands

[PaulGrandperrin]

Hello,
This nightly just broke my crate:
https://travis-ci.org/rust-fuzz/honggfuzz-rs/builds

It looks like it there has been a change in how cargo passes arguments to subcommands.

I guess we have a typical case of:

Here is the piece of code that worked before and now doesn't: https://github.com/rust-fuzz/honggfuzz-rs/blob/master/src/bin/cargo-hfuzz.rs#L169-L171

    let mut args = env::args().skip(1);
    if args.next() != Some("hfuzz".to_string()) {
        eprintln!("please launch as a cargo subcommand: \"cargo hfuzz ...\"");
        process::exit(1);
    }

Just to be clear, this is absolutely no big deal for me and I don't care adapting my code. I just want to be sure, the change in behavior is known.

[alexcrichton]

cc @matklad

[matklad]

@PaulGrandperrin if you've already investigated it, could you tell how the args looks on stable and on nightly?

[matklad]

Figured it out myself:

Before

["/home/matklad/.cargo/bin/cargo-hfuzz", "hfuzz", "clean"]

After

["/home/matklad/.cargo/bin/cargo-hfuzz", "clean"]

I can't believe we don't have a test for it...

[PaulGrandperrin]

Arg, you were fast!
Yes, that's why I felt it would be sensible to report it :-)

[matklad]

@PaulGrandperrin thank you so much for the report! We've recently switched from docopt to clap, so I've expected regressions for some obscure corner cases, but this one is as far from the spacebar heater as it gets...

[PaulGrandperrin]

Glad it helped!
And it's always fun to be able to mention XKCD strips in bug reports 😉
Thanks for your work!

[azriel91]

Hiya! I know the title says nightly 2018/03/19, but I'm wondering if this is the same issue that's causing this to happen on 1.26.0-nightly (d6c3983fe 2018-03-16):

$ cargo audit
thread 'main' panicked at 'cargo-audit is intended to be invoked as a cargo subcommand', src/main.rs:53:13
note: Run with `RUST_BACKTRACE=1` for a backtrace.

$ cargo audit audit
    Fetching advisories `https://raw.githubusercontent.com/RustSec/advisory-db/master/Advisories.toml`
    Scanning 238 crates for vulnerabilities (5 advisories in database)
     Success No vulnerable packages found

$ cargo make --version
cargo 

$ cargo make make --version
cargo-make 0.10.5

$ cargo --version --verbose
cargo 1.26.0-nightly (d6c3983fe 2018-03-16)
release: 1.26.0
commit-hash: d6c3983fe3bd8fa06b54712e53fb23645598188b
commit-date: 2018-03-16

If it's different I can raise another issue, but the test code looks like it's this one.

[matklad]

@azriel91 yep, this looks like the same issue! Hopefully the Cargo fix will to the nightlies soon