cargo-llvm-cov: init at 0.4.13

[matthiasbeyer]

Closes #170938
Supersedes #170938

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 22.11 Release Notes (or backporting 22.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[DieracDelta]

LGTM, the fetchcrate seems like it fixes ofborg. Excited to see this in nixpkgs!

[matthiasbeyer]

@FliegendeWurst unfortunately, your workaround does not work anymore with 0.4.14... care to investigate?

[winterqt]

What I'm confused about is that this should have never worked in the first place, for a few reasons:

1. Your hash for the crate source is wrong (off by one character).
2. Your patch for copying the Cargo.lock doesn't apply to the dependency tarball generation, which means the build still fails.
3. The tests depend on a nightly compiler, which we don't ship (and rustPlatform doesn't use).

Due to these reasons, I propose the following solution, which I have locally and can push if you'd like (or you can make the changes yourself):

1. Only use the crate source, we don't care about the tests fixtures
2. rm test/tests.rs in postPatch, to stop the tests that require nightly from running

Making these changes locally has this building successfully for me.

[matthiasbeyer]

With your changes, this fails now with:

rm: cannot remove 'test/tests.rs': No such file or directory

[winterqt]

Ugh, sorry, made a typo in my original message and didn't notice before repeating it: it should be rm tests/test.rs.

[matthiasbeyer]

I'm gonna use fixup patches for now and squash once all of you approve.

[DieracDelta]

Any chance we get this merged? I would love to drop my overlays for this and pull directly from nixpkgs.

[winterqt]

Should this use the same libllvm as rustc (e.g. rustPlatform.rust.rustc.llvmPackages.libllvm)?

[CobaltCause]

Not sure if this is different because it's an older version, but I didn't need to add any buildInputs at all to get 0.5.0 to build/function.

[winterqt]

Yeah, looks like libllvm was never required, at least on 0.4.13.

@DieracDelta Do you remember why you added it, out of curiosity?

[DieracDelta]

I have no recollection of adding this. If it works without libllvm, then let's drop the dependency 👍

[winterqt]

I'm happy to merge this after #185183 (comment) is figured out. I don't see why we shouldn't use the same version (smaller closure size and all), but maybe it matters?

Apologies for forgetting about this PR.

[CobaltCause]

Is there any reason not to update this PR to init at upstream's 0.5.0?

[winterqt]

I'm going to close this in favor of #197478, because it has all the tests working, and does not wrap the binary (and is the latest version).

Thanks to everyone who got this implementation where it was, and if you can see anything in there that's worth a review, don't hesitate to comment there :)