Fix Cargo mismatch on MacOS build

[SchahinRohani]

Description

The flake.nix uses the default crane toolchain on darwin. Override the default crane toolchain and specify
the target to use the correct rust toolchain.

Fixes #948

Type of change

Please delete options that aren't relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to
  not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Invoke nix build on MacOS

Checklist

• Updated documentation if needed
• Tests added/amended
• bazel test //... passes locally
• PR is contained in a single commit, using git amend see some docs

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This change is 

[allada]

+@aaronmondal

Reviewable status: 0 of 1 LGTMs obtained, and pending CI: pre-commit-checks (waiting on @aaronmondal)

[aaronmondal]

Oh this exposed a bunch of issues. Thanks a lot for looking into this.

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: 0 of 1 LGTMs obtained, and pending CI: pre-commit-checks, and 4 discussions need to be resolved (waiting on @aaronmondal)

---

-- commits line 6 at r1:

Suggestion:

to use the correct rust toolchain.

Fixes #948

---

Cargo.toml line 8 at r1 (raw file):

version = "0.4.0"
edition = "2021"
rust-version = "1.78.0"

Let's defer this to another PR. It's correct that we want this to match, but the flake change impacts darwin alone and this change impacts the build for all architectures.

Once we have the current PR landed we can bump this and then start always keeping it in sync with the version in flake.nix.

---

flake.nix line 40 at r1 (raw file):

        "x86_64-linux"
        "x86_64-darwin"
        "aarch64-linux"

Let's remove this as it's not part of the change.

---

flake.nix line 93 at r1 (raw file):

          then
            (crane.mkLib pkgs).overrideToolchain (stable-rust.default.override {
              targets = ["aarch64-apple-darwin"];

I was wondering why your PR succeeded even on the macos-13 runners which are x86_64-apple-darwin, and I think it's because the GHA workflows there are not correct. We only invoke nix build in:

nativelink/.github/workflows/nix.yaml

Line 84 in c0c09ed

installation:

This means that with your current change things pass CI but won't work as intended because you'll be cross-compiling for aarch64-darwin on any Mac, even on an x86_64-darwin system.

The way to double check against this is to instead use nix run in the installation workflow above and make the github action query whether the output of nix run is:

error: the following required arguments were not provided:
  <CONFIG_FILE>

Usage: nativelink <CONFIG_FILE>

For more information, try '--help'.

The above is what you'd get if the nativelink executable worked. If it has been compiled for a different architecture this should create a segfault or raise an error like file not found because of a mismatching dynamic loader.

[SchahinRohani]

Reviewable status: 0 of 1 LGTMs obtained, and pending CI: Analyze (javascript-typescript), Analyze (python), Bazel Dev / ubuntu-22.04, Cargo Dev / macos-13, Cargo Dev / ubuntu-22.04, Installation / macos-13, Installation / macos-14, Installation / ubuntu-22.04, Local / ubuntu-22.04, Publish image, Publish nativelink-worker-lre-cc, Remote / large-ubuntu-22.04, asan / ubuntu-22.04, docker-compose-compiles-nativelink (20.04), docker-compose-compiles-nativelink (22.04), integration-tests (20.04), integration-tests (22.04), macos-13, pre-commit-checks, ubuntu-20.04 / stable, ubuntu-22.04, ubuntu-22.04 / stable, windows-2022 / stable, and 4 discussions need to be resolved (waiting on @aaronmondal)

---

-- commits line 6 at r1:
Done.

---

flake.nix line 40 at r1 (raw file):

Previously, aaronmondal (Aaron Siddhartha Mondal) wrote…

Let's remove this as it's not part of the change.

Done.

---

flake.nix line 93 at r1 (raw file):

Previously, aaronmondal (Aaron Siddhartha Mondal) wrote…

I was wondering why your PR succeeded even on the macos-13 runners which are x86_64-apple-darwin, and I think it's because the GHA workflows there are not correct. We only invoke nix build in:

nativelink/.github/workflows/nix.yaml

Line 84 in c0c09ed

installation:

This means that with your current change things pass CI but won't work as intended because you'll be cross-compiling for aarch64-darwin on any Mac, even on an x86_64-darwin system.

The way to double check against this is to instead use nix run in the installation workflow above and make the github action query whether the output of nix run is:

error: the following required arguments were not provided:
  <CONFIG_FILE>

Usage: nativelink <CONFIG_FILE>

For more information, try '--help'.

The above is what you'd get if the nativelink executable worked. If it has been compiled for a different architecture this should create a segfault or raise an error like file not found because of a mismatching dynamic loader.

Done.

---

Cargo.toml line 8 at r1 (raw file):

Previously, aaronmondal (Aaron Siddhartha Mondal) wrote…

Let's defer this to another PR. It's correct that we want this to match, but the flake change impacts darwin alone and this change impacts the build for all architectures.

Once we have the current PR landed we can bump this and then start always keeping it in sync with the version in flake.nix.

Done.

[aaronmondal]

I believe you need to rebase. There was a CI issue with the pre-commit hooks.

Thanks a lot!

Reviewed 3 of 3 files at r3, all commit messages.
Reviewable status: 1 of 1 LGTMs obtained, and pending CI: Remote / large-ubuntu-22.04, pre-commit-checks