Re: [PATCH v2] rust: Support latest version of `rust-analyzer`

[Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>]

Hi Sarthak,

Thanks for the patch! A few notes below.

On Tue, Jul 23, 2024 at 12:41 PM Sarthak Singh
<sarthak.singh99@gmail.com> wrote:
>
> From: Sarthak Singh <ss269@uw.edu>

In case you are wondering, this line is here because you are
submitting the patch from a different email address than this one. It
would be ideal if you can submit from the address that you are
signing-off-by (if you cannot, please send me a dummy private message
from that address).

> Sets the `sysroot` field in rust-project.json which is now needed in
> newer versions of rust-analyzer instead of the `sysroot_src` field.
>
> `sysroot` over `sysroot_src` has been working since rust 1.74.0 (which
> was released on Nov 16, 2023). Since we are going to target rust 1.78.0
> going forward we should set `sysroot` to support all currently used and
> future versions of rust-analyzer.

Hmm... it would be nice to know the root cause, i.e. what changed in
rust-analyzer?

From a quick look, the `sysroot` key has existed in rust-analyzer
since 2022 (189521a4db6e), but undocumented. Then it got documented in
2023 (5da14237eb29). So I am not sure what "`sysroot` over
`sysroot_src`" means (and the current docs are not very clear on what
each does and their intended interactions, e.g. what happens if one
specifies `sysroot_src` but not `sysroot`, or the other way around?
Should `sysroot_src` be relative to `sysroot` like the default?)

Anyway, we are passing the paths for `core` etc. in `crates`, and we
don't have a custom `alloc` anymore, so I wonder if we should either
delete both keys (or however one disables auto-search) or delete the
crates in `crates` and let the sysroot logic find them.

(Cc'ing Lukas since he may able to tell us about the background.)

> Code editors like VS Code try to use the latest version of rust-analyzer
> (which is updated every week) instead of the version of rust-analyzer
> that comes with the rustup toolchain (which is updated every six weeks
> along with the rust version).
>
> Without this change rust-analyzer is breaking for anyone using VS Code.

Just to confirm, does this make it work for distribution and
`rustup`-using installs?

> Signed-off-by: Sarthak Singh <ss269@uw.edu>

Dirk gave a Tested-by tag to v1 -- normally you would pick up those
tags if you submit a new version and you consider them still valid
(before the Signed-off-by). I think you didn't change the contents of
the patch, right?

Cheers,
Miguel