Passing arguments to underlying invocations of cargo

[artemagvanian]

I wonder if it is possible to run dylint lint pass with -Z build-std passed to all underlying cargo invocations. One of the lints I am writing depends on having standard library MIR accessible during the compilation. While it is possible to achieve this by configuring the crate on which the lint runs, it would be ideal to have this behavior out of the box for the end user.

[smoelius]

Might this work?

cargo dylint ... -- -Z build-std

The arguments after -- are forwarded to cargo check, which cargo dylint runs under the hood.

[artemagvanian]

That worked! Thanks!

[artemagvanian]

A follow-up on the previous question: is it possible to do the same thing with dylint_testing?

[smoelius]

Hmm. dylint_testing is a wrapper around compiletest-rs, which runs rustc directly. Furthermore, dylint_testing has a "test builder" that allows one to pass flags to rustc.

For example, here it used to pass the --test flag to rustc:

dylint/examples/general/abs_home_path/src/lib.rs

Lines 155 to 160 in 39c6cd9

	dylint_testing::ui::Test::src_base(
	env!("CARGO_PKG_NAME"),
	&Path::new(env!("CARGO_MANIFEST_DIR")).join("ui"),
	)
	.rustc_flags(["--test"])
	.run();

So if one could figure out what flags Cargo passes to rustc when -Z build-std is enabled, one could pass them to rustc using a test builder.

At least, I think that should work.

[artemagvanian]

Thanks again! Unfortunately, it was more complicated than just passing flags to rustc, so we ended up building a simple test harness that runs dylint directly and diffs the outputs.

[smoelius]

Thanks, I was curious to know how this went. Can I ask what more was required?

[artemagvanian]

From what I could gather, it would require manually resolving std, setting up a fake workspace for it, and then linking it as an extern. If you are interested, this is the first PR for cargo build-std that briefly explains how they do it

[artemagvanian]

On the other note, I opened this issue in compiletest, so maybe someone who knows more than me could give their opinion

[smoelius]

Thanks for the explanation. It is unfortunate that dylint_testing did not help here, but I am glad you were able to find a solution.