cargo udeps panic

[Sherlock-Holo]

when I run cargo udeps for my project, the udeps panic, it panic at

errorthread '<unnamed>' panicked at 'invalid format for extern arg: proc_macro', /home/sherlock/.cargo/registry/src/mirrors.ustc.edu.cn-61ef6e0cd06fb9b8/cargo-udeps-0.1.9/src/lib.rs:580:25: worker panicked

however I run cargo check, it runs successfully.

[est31]

Do you have a minimally reproducible example?

[Sherlock-Holo]

my project is a littile big, link

I will try to find a minimally reproducible example, and you can download my project to find out why panic. Sorry for I can't find a minimally reproducible example at first time

[est31]

Nevermind I have found an example. It seems to occur in cargo-udeps 0.1.9 first. Thanks for the report.

To reproduce one needs to clone https://github.com/dtolnay/proc-macro-hack and then run cargo +nightly udeps -p demo-hack in it.

[qryxip]

Probably because of this.

this change will mean that you can delete the extern crate proc_macro; line

$ rustc +1.35.0 --help -v | rg -- --extern
        --extern NAME=PATH
        --extern-private NAME=PATH
$ rustc +stable --help -v | rg -- --extern
        --extern NAME[=PATH]
$ touch src/lib.rs && cargo +nightly check -v
       Fresh unicode-xid v0.2.0
       Fresh proc-macro2 v1.0.9
       Fresh quote v1.0.3
       Fresh syn v1.0.16
    Checking proc-macro-hack v0.5.11 (/home/ryo/src/github.com/dtolnay/proc-macro-hack)
     Running `rustc --crate-name proc_macro_hack --edition=2018 src/lib.rs --error-format=json --json=diagnostic-rendered-ansi --crate-type proc-macro --emit=dep-info,metadata -C prefer-dynamic -C debuginfo=2 -C metadata=60734e183005d2f3 -C extra-filename=-60734e183005d2f3 --out-dir /home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/deps -C incremental=/home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/incremental -L dependency=/home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/deps --extern proc_macro2=/home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/deps/libproc_macro2-4610c0a0f83155c0.rmeta --extern quote=/home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/deps/libquote-68ac4f6b444e17b8.rmeta --extern syn=/home/ryo/src/github.com/dtolnay/proc-macro-hack/target/debug/deps/libsyn-5ffea411d71f0934.rmeta --extern proc_macro`
    Finished dev [unoptimized + debuginfo] target(s) in 0.21s

cargo-udeps/src/lib.rs

Lines 576 to 581 in 80b1060

	let mut splitter = a.split("=");
	if let (Some(n), Some(p)) = (splitter.next(), splitter.next()) {
	(n.to_owned(), p.to_owned())
	} else {
	panic!("invalid format for extern arg: {}", a);
	}

[est31]

Thanks @qryxip for the quick fix. I've released 0.1.10 because of the large impact of the bug.