Re: [PATCH V2] docs: rust: Clarify that 'rustup override' applies to build directory

[Tiago Lam <tiagolam@gmail.com>]

On 15/12/2023 06:48, Viresh Kumar wrote:
> On 14-12-23, 18:22, Miguel Ojeda wrote:
>> Something like v1 but a bit simpler, e.g. keeping things as they are,
>> but with just a sentence after the command like "If you are building
>> the kernel with `O=`, i.e. specifying an output directory, then you
>> should append `--path <builddir>`." could work.
>>
>> Or we could just provide a `rustupoverride` Make target to do this for
>> us [1], since we have all the information needed and would be
>> copy-pasteable by everybody. I can send it as a non-mangled patch and
>> then Viresh can redo this one on top using it.
> 
> How about this ?
> 
> diff --git a/Documentation/rust/quick-start.rst b/Documentation/rust/quick-start.rst
> index f382914f4191..367b06f3edc2 100644
> --- a/Documentation/rust/quick-start.rst
> +++ b/Documentation/rust/quick-start.rst
> @@ -39,8 +39,17 @@ If ``rustup`` is being used, enter the checked out source code directory
>          rustup override set $(scripts/min-tool-version.sh rustc)
> 
>   This will configure your working directory to use the correct version of
> -``rustc`` without affecting your default toolchain. If you are not using
> -``rustup``, fetch a standalone installer from:
> +``rustc`` without affecting your default toolchain.
> +
> +If you are building the kernel with `O=`, i.e. specifying an output
> +directory, then you should append `--path <builddir>` to the above
> +command.
> +

I think we can drop the reference to the `--path <buildir>` to avoid 
giving too much information to the users following the guide. It doesn't 
seem to bring anything given users should now always go through `make 
rustupoverride`.

> +Alternatively, you can use the ``rustupoverride`` Make target::
> +
> +       make LLVM=1 O=<builddir> rustupoverride
> +

But if I understood this correctly, the point here is that with the new 
target we can now abstract both cases behind the `make rustupoverride` 
target - i.e. we don't need to provide alternatives. So, maybe something 
like the following is clearer:

	If ``rustup`` is being used, enter the checked out source code 
directory, or your build directory (if you're using the `O=` option to 
build the kernel), and run::

         	make LLVM=1 rustupoverride

	This will configure your current directory to use the correct version 
of ``rustc`` without affecting your default toolchain.

	If you are not using ``rustup``, fetch a standalone installer from:
      	 
https://forge.rust-lang.org/infra/other-installation-methods.html#standalone

Tiago.