On Apple silicon machines, the brew installed llvm's `wasm-ld` linker does not seem to be detected by juvix doctor command.

Describe the bug

I am Apple M1 Pro (OS: macos sonoma) and I installed juvix. juvix itself installs fine but juvix doctor command is not being able to detect my wasm-ld installed locally. (I do want to compile to WebAssembly)

On Apple silicon macos machines, the brew installed llvm's wasm-ld linker does not seem to be detected by juvix doctor command. I also tried installing and building wasm-ld directly (https://lld.llvm.org/). But either way, wasm-ld is not detected by juvix doctor.

> juvix --version
Juvix version 0.6.6-e4559bb
Branch: HEAD
Commit: e4559bbc87eb946c1b5c4db76ec8983a94201418
Date: Tue Sep 3 18:10:01 2024 +0100
> juvix doctor
> Checking for clang...
> Checking clang version...
> Checking for wasm-ld...
  ! Could not find the wasm-ld command
  ! https://docs.juvix.org/0.6.6/reference/tooling/doctor/#could-not-find-the-wasm-ld-command
> Checking that clang supports wasm32...
> Checking that clang supports wasm32-wasi...
> Checking that WASI_SYSROOT_PATH is set...
> Checking for wasmer...
> Checking latest Juvix release on Github...
> which wasm-ld
/usr/local/bin/wasm-ld
> brew --prefix llvm
/opt/homebrew/opt/llvm

Can anyone help me here? Not sure if this is the issue with the llvm setup on my local mac or the juvix doctor.

Desktop (please complete the following information):

Machine: Apple M1 Pro
OS: MacOS 14.6.1 Sonoma
Juvix Version: 0.6.6-e4559bb

To Reproduce Steps to reproduce the behavior: https://docs.juvix.org/0.6.3/howto/installing.html

Expected behavior

juvix doctor to detect locally installed wasm-ld

Hi 👋 - thanks for the report.

To summarise:

wasm-ld and a WASM compatible clang are only required if you want to use Juvix's WASM target. This is not necessary if you want to compile Anoma applications.
You can ignore the juvix doctor warning if you have installed wasm-ld yourself. But note that the active version of clang should match the active version of wasm-ld.
You can install wasm-ld using brew by installing the lld package: brew install lld.

What follows is a more detailed description of what we need to fix.

1. `wasm-ld` is no longer present in the homebrew `llvm` package

wasm-ld was removed from the llvm package in the latest version (version 19).

$ brew ls -v llvm@18 | grep wasm-ld
/opt/homebrew/Cellar/llvm@18/18.1.8/bin/wasm-ld
$ brew ls -v llvm | grep wasm-ld

wasm-ld is installed by the lld homebrew package.

$ brew ls -v lld | grep wasm-ld
/opt/homebrew/Cellar/lld/19.1.0/bin/wasm-ld

Actions

Update the install documentation for macOS with instructions for installing wasm-ld using the lld homebrew package.

2. The `juvix doctor` diagnosis is misleading

We require that the doctor checks that:

wasm-ld is available on the user's PATH
wasm-ld is compatible with the version of clang on the user's PATH

We currently do this by checking that wasm-ld exists in the llvm distribution.

https://github.com/anoma/juvix/blob/8c37d9b439acc66455cff963a11821bbd0ac15b4/app/Commands/Doctor.hs#L77-L80

For macOS the implemented check does not cover the two requirements.

Actions

Update the implemented check to meet the requirements.
Update the warning message and documentation to more accurately describe what's being checked.

3. The `juvix` doctor links are broken

For example:

$ curl -s -o /dev/null -w "%{http_code}\n" https://docs.juvix.org/0.6.6/reference/tooling/doctor/#could-not-find-the-wasm-ld-command
404

Actions

Fix this as part of

https://github.com/anoma/juvix/issues/3078

4. The WASM dependencies are highlighted in the install docs but are not required for Anoma.

The Juvix WASM backend was developed at a time when Anoma applications were represented as WASM code. This is no longer the case and so it's not important for Juvix users of Anoma to setup WASM tooling. The Juvix documentation and doctor make it seem like WASM setup is important.

Actions

Deemphasise WASM tooling in docs https://github.com/anoma/juvix/issues/3078
Make WASM support optional: https://github.com/anoma/juvix/issues/3077

anoma / juvix