Error with wasm32-unknown-unknown only on github action workers

[nfachan]

Hello.

I've been scratching my head on this for a while, and I'm not sure what to do. We have some scripts meant for use in CI. They invoke nix develop and then run various cargo commands. These work well for local development, but fail on GitHub. In particular, the wasm32-unknown-unknown target doesn't get installed on GitHub workers.

Here's the flake.nix.
Here's a build step where the wasm32-unknown-unknown target isn't available.
Here's a build step where we use vanilla nix build and it does work.

This is what our wrapper script looks like.
This is what an inner script looks like.

[ipetkov]

I'm not entirely certain what is happening there. Here's a few points which may be of interest:

error[E0463]: can't find crate for core
error[E0463]: can't find crate for compiler_builtins

If any part of your build is requiring the sources of stdlib crates to be built, you may need to add extensions = [ "rust-src" ]; to your rustToolchain. Take a look at https://crane.dev/examples/build-std.html for more info

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I noticed that this build script is running a cargo build from inside of a cargo build. Not sure if there could be some funny business there (maybe the inner invocation is not inheriting arguments/environment variables properly?).

I would consider debugging that invocation directly in your CI and see if anything interesting pops up...

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Hope this helps!

[nfachan]

Thanks for the thoughtful reply.

Upon more digging, I've found that -- for a reason I've not yet determined -- the PATH passed to the build script has ~/.cargo/bin prepended to it in CI, and that path has a cargo binary in it. So, something interesting did pop up.

Now I have to figure out why cargo is doing that!

[nfachan]

I haven't yet gotten to the bottom of why cargo (it seems) is prepending to the PATH. But I was able to solve the issue by removing the .cargo/bin directory in CI.

Thanks for your help!