MacOS Sequoia 15.5: coreaudio-sys v0.2.17 fails to build with 'AudioUnit/AudioUnit.h' file not found

[Sycrosity]

When compiling a bevy project (here), coreaudio-sys fails to build with the following error with cargo version 1.87.0 (99624be96 2025-05-06) and rustc version rustc 1.87.0 (17067e9ac 2025-05-09):

cargo run:

   Compiling clang-sys v1.8.1
   Compiling bindgen v0.72.0
   Compiling coreaudio-sys v0.2.17
error: failed to run custom build command for `coreaudio-sys v0.2.17`

Caused by:
  process didn't exit successfully: `/Users/____/____/target/debug/build/coreaudio-sys-dc6d289bbf85bc6d/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=COREAUDIO_SDK_PATH
  cargo:rustc-link-lib=framework=AudioUnit
  cargo:rustc-link-lib=framework=CoreAudio
  cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS

  --- stderr
  /Users/___/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/coreaudio-sys-0.2.17/coreaudio.h:1:10: fatal error: 'AudioUnit/AudioUnit.h' file not found

  thread 'main' panicked at /Users/____/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bindgen-0.72.0/lib.rs:917:13:
  assertion `left == right` failed: "arm64-apple-darwin" "aarch64-apple-darwin"
    left: 4
   right: 8
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

or cargo run --release:

error: failed to run custom build command for `coreaudio-sys v0.2.17`

Caused by:
  process didn't exit successfully: `/Users/louis/dev/games/mini-motorways/target/release/build/coreaudio-sys-fad6d50638531b0a/build-script-build` (exit status: 101)
  --- stdout
  cargo:rerun-if-env-changed=COREAUDIO_SDK_PATH
  cargo:rustc-link-lib=framework=AudioUnit
  cargo:rustc-link-lib=framework=CoreAudio
  cargo:rerun-if-env-changed=BINDGEN_EXTRA_CLANG_ARGS

  --- stderr
  /Users/louis/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/coreaudio-sys-0.2.17/coreaudio.h:1:10: fatal error: 'AudioUnit/AudioUnit.h' file not found

  thread 'main' panicked at /Users/louis/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/coreaudio-sys-0.2.17/build.rs:150:39:
  unable to generate bindings: ClangDiagnostic("/Users/louis/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/coreaudio-sys-0.2.17/coreaudio.h:1:10: fatal error: 'AudioUnit/AudioUnit.h' file not found\n")
  note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

Forcing the program to run with coreaudio-sys v0.2.16 functions as expected, as does v0.2.15.

Running: cargo update coreaudio-sys --precise 0.2.16 followed by cargo run:

Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.26s

I am not using Nix.

Any ideas on why this might be? The only update to core-audio-sys in v0.2.17 has been bumping bingen.

[simlay]

Huh. That is weird. I checked out your mini-motorways repo and it built on my m1 macbook pro for macOS 15.5. I'm using xcode 26 (beta). CI on this repo uses the default xcode - currently this is xcode 16. The difference between 0.2.16 and 0.2.17 is pretty small and doesn't seem like it should be an issue

I think you need to upgrade xcode. Xcode 16-ish shipped a new version of clang and that version of clang changed the target triples. #112 and rust-lang/rust-bindgen#3182 were the fixes.

Bleh, I guess the bump from 0.2.16 to 0.2.17 was breaking. My bad. There's been changes to cpal, coraudio-rs and bevy to avoid this problem in the future.

[Sycrosity]

Strange - according to macOS and Xcode I have the latest xcode version? 16.4 (16F6)

[Sycrosity]

I was trying to dig into this issue in the bindgen repo:

  thread 'main' panicked at /Users/____/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/bindgen-0.72.0/lib.rs:917:13:
  assertion `left == right` failed: "arm64-apple-darwin" "aarch64-apple-darwin"
    left: 4
   right: 8

And while it has my correct platform and converts it correctly (the failed: "arm64-apple-darwin" "aarch64-apple-darwin" message confusingly is in the format "{effective_target:?} {HOST_TARGET:?}", the assert actually checks the target pointer size against size_of::<*mut ()>()). It seems to be that the clag::TargetInfo it is using is TargetInfo { triple: "riscv32-esp-unknown-elf", pointer_width: 32, abi: GenericItanium }, which would explain the exception (left: 4 is target_info.pointer_width/8, while right: is 64/8).

Which is especially confusing as this "target info" is created after the /Users/louis/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/coreaudio-sys-0.2.17/coreaudio.h:1:10: fatal error: 'AudioUnit/AudioUnit.h' file not found error is generated.

[Sycrosity]

$ clang --version   
                                                                                                                                     
Apple clang version 17.0.0 (clang-1700.0.13.5)
Target: arm64-apple-darwin24.5.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

[simlay]

Hmm. You don't by chance have LIBCLANG_PATH set? Like, if you've used espup and such, it comes with it's own version of clang and breaks things in weird ways. Like, for me I have LIBCLANG_PATH="/Users/simlay/.rustup/toolchains/esp/xtensa-esp32-elf-clang/esp-16.0.0-20230516/esp-clang/lib" and when I touch anything with bindgen outside of esp stuff, i've gotta unset LIBCLANG_PATH

[Sycrosity]

Right before seeing your message I checked printenv on a hunch and saw it was set to /Users/___/.rustup/toolchains/esp/xtensa-esp32-elf-clang/esp-18.1.2_20240912/esp-clang/lib and set it to the Xcode clang lib path, which fixed the issue! Clearly it got set at some point by espup or some other tool - it was exactly that.
Thanks for the help!