Suggested rust-analyzer config can't run rustfmt

[jyn514]

#107297 broke the rust-analyzer config we suggest in the dev-guide: https://rustc-dev-guide.rust-lang.org/building/suggested.html#configuring-rust-analyzer-for-rustc

    "rust-analyzer.rustfmt.overrideCommand": [
        "./build/host/stage0/bin/rustfmt",
        "--edition=2021"
    ],

since now rustfmt is in build/host/rustfmt/bin/rustfmt instead of build/host/stage0/bin/rustfmt.

Originally posted by @jyn514 in #107297 (comment)

[zephaniahong]

@rustbot claim

[zephaniahong]

Hi! Just to clarify, the idea is to change to code to match the docs?

[albertlarsan68]

I think the idea is changing the docs to match the new behavior.

[zephaniahong]

For reference: rust-lang/rustc-dev-guide#1574

[jyn514]

I'd prefer to change the code so that we don't force all contributors to update their config.

[Mark-Simulacrum]

I don't think we can put the binary back, or at least, that feels iffy - we'd be trying to overlap two different sysroots. rustfmt used to be statically linked to libstd and librustc_driver, but that's no longer the case.

[Mark-Simulacrum]

I suppose we could try to create a symlink from the old path to the new one? That might work, not sure.

[albertlarsan68]

Maybe add a proxy?
On Linux it might just be

#!/usr/bin/sh
exec ../rustdoc $* #FIXME make this syntax correct

[jyn514]

A symlink seems like a good solution to me.

[albertlarsan68]

Does the symlink still finds the correct so?

[jyn514]

✨ try it and see ✨

[zephaniahong]

I'll experiment adding a symlink.

[albertlarsan68]

On Windows, creating a symlink does not find the needed DLLs.
Trying to execute the symlink pops two msgbox saying that it doesn't find the rustc_driver and std DLLs.
You would need to symlink also the DLLs.
On Linux, it does find the correct SOs.

[kadiwa4]

Symlinking also works on macOS.

[jyn514]

On Windows, creating a symlink does not find the needed DLLs. Trying to execute the symlink pops two msgbox saying that it doesn't find the rustc_driver and std DLLs. You would need to symlink also the DLLs. On Linux, it does find the correct SOs.

Ok, this is pretty messy. How about doing both:

• Add the symlink, which will work with both the old and new config on Mac and Linux
• Update the recommended config in the dev-guide, which will help contributors fix the error message on Windows

and from there we can work long-term to using the same toolchain for rustfmt and other tools, without having a time pressure.

[jyn514]

and from there we can work long-term to using the same toolchain for rustfmt and other tools, without having a time pressure.

cc rust-lang/rustfmt#4884, rust-lang/rustfmt#3900

[zephaniahong]

May I get some guidance and the creation of the symlink? Do I use rust to create the symlink in src/bootstrap/download.rs after the rustfmt_path line or do I use a bash command? If I do use a bash command, is there a file I should be adding it to?

Thank you!

[jyn514]

@zephaniahong use

rust/src/bootstrap/lib.rs

Line 1593 in 99529b0

fn symlink_file<P: AsRef<Path>, Q: AsRef<Path>>(&self, src: P, link: Q) -> io::Result<()> {

[zephaniahong]

And just to confirm, I use that symlink function here?

rust/src/bootstrap/download.rs

Lines 332 to 333 in 11d96b5

	let rustfmt_path = bin_root.join("bin").join(exe("rustfmt", host));
	let rustfmt_stamp = bin_root.join(".rustfmt-stamp");

[jyn514]

yes

[bjorn3]

I think it would be possible to move rustfmt back to the same sysroot as the bootstrap compiler by only taking libstd.so, librustc_middle.so and libLLVM.so from the nightly rustc component and not copying any other files like the rustc binary. Libstd.so and librustc_middle.so both contain a hash in their name unique for each rustc version. libLLVM.so should contain the rustc version, so that shouldn't conflict either.

[albertlarsan68]

Doing the same with the DLLs on Windows could also work.

[est31]

related (different error with rustfmt, but caused by the same change): #107676

[jyn514]

Hi @zephaniahong, any progress on the symlink? happy to help out if you're running into trouble :)

[zephaniahong]

Hey @jyn514 ! Thanks for reaching out! I'll be starting tomorrow and will reach out to you if/when I need help!
Apologies for the delay!