internal: project-model: when using `rust-project.json`, prefer the sysroot-defined rustc over discovery in `$PATH` #15560

davidbarsky · 2023-09-05T19:43:24Z

At the moment, rust-analyzer discovers rustc via the $PATH even if the sysroot field is defined in a rust-project.json. However, this does not work for users who do not have rustup installed, resulting in any cfg-based inference in rust-analzyer not working correctly. In my (decently naive!) opinion, it makes more sense to rely on the sysroot field in the rust-project.json.

One might ask "why not add rustc to the $PATH?" That is a reasonable question, but that doesn't work for my use case:

The path to the sysroot in my employer's monorepo changes depending on which platform a user is on. For example, if they're on Linux, they'd want to use the sysroot defined at path a, whereas if they're on macOS, they'd want to use the sysroot at path b (I wrote the sysroot resolution functionality here, if you're curious).
The location of the sysroot can (and does!) change, especially as people figure out how to make Rust run successfully on non-Linux platforms (e.g., iOS, Android, etc.) in a monorepo. Updating people's $PATH company-wide is hard while updating a config inside a CLI is pretty easy.

Testing

I've created a rust-project.json using rust-project and was able to successfully load a project with and without the sysroot/sysroot_src fields—without those fields, rust-analyzer fell back to the $PATH based approach, as evidenced by [DEBUG project_model::rustc_cfg] using rustc from env rustc="rustc" showing up in the logs.

…ined rustc over an env-based one

davidbarsky

No rush on reviewing this, but I wanted to leave comments on the approach I took here since changes inside of project-model can be kinda tricky.

crates/project-model/src/rustc_cfg.rs

davidbarsky · 2023-09-07T19:20:39Z

crates/project-model/src/rustc_cfg.rs

-use crate::{cfg_flag::CfgFlag, utf8_stdout, ManifestPath};
+use crate::{cfg_flag::CfgFlag, utf8_stdout, ManifestPath, Sysroot};
+
+pub(crate) enum RustcCfgConfig<'a> {


The name here is a little generic, but I'm struggling to think of anything better. In any case, I hope that the doc comment helps a little.

The entire module is slightly mislabeled by now I feel like, not sure what a better name for this would be though. Maybe builtin_cfg and the like

builtin_cfg is a good option. While we're bikeshedding, what do you think something like target_cfg since the output consists of things like:

``` rust-analyzer on davidbarsky/use-sysroot-rustc-to-determine-cfgs [$] via 🦀 v1.71.0 ❯ rustc --print cfg -O panic="unwind" target_arch="aarch64" target_endian="little" target_env="" target_family="unix" target_feature="aes" target_feature="crc" target_feature="dit" target_feature="dotprod" target_feature="dpb" target_feature="dpb2" target_feature="fcma" target_feature="fhm" target_feature="flagm" target_feature="fp16" target_feature="frintts" target_feature="jsconv" target_feature="lor" target_feature="lse" target_feature="neon" target_feature="paca" target_feature="pacg" target_feature="pan" target_feature="pmuv3" target_feature="ras" target_feature="rcpc" target_feature="rcpc2" target_feature="rdm" target_feature="sb" target_feature="sha2" target_feature="sha3" target_feature="ssbs" target_feature="vh" target_has_atomic="128" target_has_atomic="16" target_has_atomic="32" target_has_atomic="64" target_has_atomic="8" target_has_atomic="ptr" target_os="macos" target_pointer_width="64" target_vendor="apple" unix ```

crates/project-model/src/rustc_cfg.rs

crates/project-model/src/sysroot.rs

Veykril

Sounds reasonable to me

crates/project-model/src/rustc_cfg.rs

Veykril · 2023-09-08T07:54:12Z

@bors delegate+

bors · 2023-09-08T07:54:15Z

✌️ @davidbarsky, you can now approve this pull request!

If @Veykril told you to "r=me" after making some further change, please make that change, then do @bors r=@Veykril

Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

davidbarsky · 2023-09-08T18:14:19Z

@bors r=@Veykril

bors · 2023-09-08T18:14:21Z

📌 Commit 0bf6ffa has been approved by Veykril

It is now in the queue for this repository.

bors · 2023-09-08T18:14:27Z

⌛ Testing commit 0bf6ffa with merge c405509...

bors · 2023-09-08T18:30:44Z

☀️ Test successful - checks-actions
Approved by: Veykril
Pushing c405509 to master...

rustbot added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Sep 5, 2023

davidbarsky added 2 commits September 7, 2023 11:46

project-model: when using rust-project.json, prefer the sysroot-def…

5b5bce8

…ined rustc over an env-based one

refactor rustc_cfg to be more inline with docs/dev/style.md

553152e

davidbarsky force-pushed the davidbarsky/use-sysroot-rustc-to-determine-cfgs branch from 839409a to 553152e Compare September 7, 2023 19:07

davidbarsky added 2 commits September 7, 2023 15:19

rename rustc_cfg::Config to rustc_cfg::RustcCfgConfig and import

fad3823

add doc comment to rustc_cfg::RustcCfgConfig

912b22f

davidbarsky commented Sep 7, 2023

View reviewed changes

Veykril approved these changes Sep 8, 2023

View reviewed changes

crates/project-model/src/rustc_cfg.rs Outdated Show resolved Hide resolved

Veykril added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 8, 2023

Update crates/project-model/src/rustc_cfg.rs

0bf6ffa

Co-authored-by: Lukas Wirth <lukastw97@gmail.com>

bors merged commit c405509 into rust-lang:master Sep 8, 2023

davidbarsky deleted the davidbarsky/use-sysroot-rustc-to-determine-cfgs branch September 8, 2023 20:53

lnicola changed the title ~~project-model: when using rust-project.json, prefer the sysroot-defined rustc over discovery in $PATH~~ internal: project-model: when using rust-project.json, prefer the sysroot-defined rustc over discovery in $PATH Sep 9, 2023

darichey mentioned this pull request Feb 27, 2024

fix: Set RUSTUP_TOOLCHAIN and invoke the proxies instead of directly invoking sysroot binaries #16563

Merged

internal: project-model: when using rust-project.json, prefer the sysroot-defined rustc over discovery in $PATH #15560

internal: project-model: when using rust-project.json, prefer the sysroot-defined rustc over discovery in $PATH #15560

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davidbarsky commented Sep 5, 2023

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internal: project-model: when using `rust-project.json`, prefer the sysroot-defined rustc over discovery in `$PATH` #15560

internal: project-model: when using `rust-project.json`, prefer the sysroot-defined rustc over discovery in `$PATH` #15560