chore: Debug Netlify Build

[davidbarsky]

It seems like netlify/build-image#477 might have broken our documentation previews, but in fairness to Netlify, I think we were the only ones who were doing a "render and deploy cargo doc" for each PR. Here's what I think is happening with netlify/build-image#477:

1. The cache_cwd_directory function (callsite, definition) moves Cargo's build output to $NETLIFY_CACHE_DIR.
2. cache_cwd_directory calls move_cache, which removes the Cargo-generated target directory. This explains why we see errors from Netlify that informing us that "target/doc does not exist".

To get around this, I've tried to change the output directory to not be target, but that's not sufficient.

[mraerino]

Hi! We use a bunch of Rust at Netlify and I started using it to publish docs for private crates since we introduced support for rustup yesterday.
I haven't looked closely, but i can try to give some clues.

If you have a rust-toolchain file (old or new format) cargo should be able to automatically install the correct toolchain for you, so your build command could be reduced to just cargo doc --no-deps.

[davidbarsky]

Hi! We use a bunch of Rust at Netlify and I started using it to publish docs for private crates since we introduced support for rustup yesterday.

That's rad!

I haven't looked closely, but i can try to give some clues.

I know it's a bit late for you, but I've written a more extensive writeup of what I think happened here: netlify/build-image#505. I'd be happy to move the discussion wherever.

If you have a rust-toolchain file (old or new format) cargo should be able to automatically install the correct toolchain for you, so your build command could be reduced to just cargo doc --no-deps.

That's a pretty handy feature! Unfortunately, I don't think a rust-toolchain will easily work with our MSRV tests or our (nightly-only) documentation previews.

[mraerino]

i opened a PR here that should work: #1131