rustfmt broken on macOS Darwin with Library not loaded: @rpath/librustc_driver-fd9e092a1dc273d5.dylib

[jfly]

Describe the bug

rustfmt is broken on macOS.

Steps To Reproduce

$ nix shell github:NixOS/nixpkgs/120a26f8ce32ac2bdc0e49a9fed830b7446416b4#rustfmt   
$ rustfmt
dyld[5882]: Library not loaded: @rpath/librustc_driver-fd9e092a1dc273d5.dylib
  Referenced from: <774D4B03-B253-3815-924D-F0C9E4D55A23> /nix/store/2kffhdn8xlk1s7zjxgbw5x3447n4dd70-rustfmt-1.74.0/bin/rustfmt
  Reason: tried: '/nix/store/i2q9ff0fpgr20zza6kr6nlpki6mn43if-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/nix/store/i2q9ff0fpgr20zza6kr6nlpki6mn43if-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/nix/store/i2q9ff0fpgr20zza6kr6nlpki6mn43if-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/nix/store/i2q9ff0fpgr20zza6kr6nlpki6mn43if-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/usr/local/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/usr/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file, not in dyld cache)
zsh: abort      rustfmt

Here's the output of otool if it's helpful:

$ otool -L `which rustfmt`
/nix/store/2kffhdn8xlk1s7zjxgbw5x3447n4dd70-rustfmt-1.74.0/bin/rustfmt:
	@rpath/librustc_driver-fd9e092a1dc273d5.dylib (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libstd-03c53b54a0b1f97d.dylib (compatibility version 0.0.0, current version 0.0.0)
	/nix/store/a78xnmg223s3iffja69ydg6sswbwd3i3-libiconv-50/lib/libiconv.dylib (compatibility version 7.0.0, current version 7.0.0)
	/nix/store/z4by244ay1bc3axm8m4816jywfhf2v5w-zlib-1.3/lib/libz.dylib (compatibility version 1.0.0, current version 1.3.0)
	/nix/store/xnvy5pf8v1fa5jac1mxhg21f03n1gk2g-llvm-16.0.6-lib/lib/libLLVM.dylib (compatibility version 1.0.0, current version 16.0.6)
	/nix/store/p5wr7bxrs2naa4rwy9sqs19rljr7g7qh-libcxx-16.0.6/lib/libc++.1.0.dylib (compatibility version 1.0.0, current version 1.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1292.60.1)
	/System/Library/Frameworks/CoreFoundation.framework/Versions/A/CoreFoundation (compatibility version 150.0.0, current version 1770.255.0)

Expected behavior

rustfmt should run without crashing =)

Additional context

This feels like a recurrence of #231078

Notify maintainers

@globin @basvandijk

Metadata

Please run nix-shell -p nix-info --run "nix-info -m" and paste the result.

$ nix-shell -p nix-info --run "nix-info -m"
 - system: `"aarch64-darwin"`
 - host os: `Darwin 23.2.0, macOS 14.2`
 - multi-user?: `yes`
 - sandbox: `no`
 - version: `nix-env (Nix) 2.18.1`
 - nixpkgs: `/nix/store/vf6skxhiqknlnqcxh8n4z2jldzzpb171-source`

[Samyak2]

WIP bisect log

[jfly]

After a very long time spent bisecting, I now know this was introduced by 8b51cdd (@alyssais since you authored this).

Broken in 8b51cdd:

jeremy@Jeremys-MBP nixpkgs % nix run nixpkgs/8b51cdd3bea18e806e3ed63add8e19292dfc84ec#rustfmt -- --version 
dyld[97738]: Library not loaded: @rpath/librustc_driver-fd9e092a1dc273d5.dylib
  Referenced from: <no uuid> /nix/store/imwqzd4864wz7g3jh2r6ghqggvrsc0mf-rustfmt-1.74.0/bin/rustfmt
  Reason: tried: '/nix/store/d16gx9vprzhrdqpabx7mjr2q5nma8ylg-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/nix/store/d16gx9vprzhrdqpabx7mjr2q5nma8ylg-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/nix/store/d16gx9vprzhrdqpabx7mjr2q5nma8ylg-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/System/Volumes/Preboot/Cryptexes/OS/nix/store/d16gx9vprzhrdqpabx7mjr2q5nma8ylg-rustc-wrapper-1.74.0/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/usr/local/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file), '/usr/lib/librustc_driver-fd9e092a1dc273d5.dylib' (no such file, not in dyld cache)
zsh: abort      nix run nixpkgs/8b51cdd3bea18e806e3ed63add8e19292dfc84ec#rustfmt -- --version

Working in c6f3c04 (the parent of 8b51cdd):

jeremy@Jeremys-MBP nixpkgs % nix run nixpkgs/c6f3c0403fd012327b69b6cd475aeee7c6ae9592#rustfmt -- --version
rustfmt 1.6.0-

[alyssais]

Ah I see, it's trying to load librustc_driver from the wrapper's lib directory, where it doesn't exist. I wonder how rustfmt decides where to load that from. Can we change that, or does the wrapper need to pass through lib?

[alyssais]

On Linux it links correctly:

librustc_driver-176f96622de184df.so => /nix/store/792bs5larfnxcrhwy8cqkgky6n72grsf-rustc-1.74.0/lib/rustlib/aarch64-unknown-linux-gnu/lib/librustc_driver-176f96622de184df.so (0x0000fffee6560000)

So this needs some investigation from somebody on Darwin to determine what's different about linking there, and how it ends up using the wrong path.

[Samyak2]

I suspect it might be because of these darwin specific prefixup commands:

nixpkgs/pkgs/development/compilers/rust/rustfmt.nix

Lines 24 to 27 in fa063ba

	preFixup = lib.optionalString stdenv.isDarwin ''
	install_name_tool -add_rpath "${rustc}/lib" "$out/bin/rustfmt"
	install_name_tool -add_rpath "${rustc}/lib" "$out/bin/git-rustfmt"
	'';

Changing rustc to rustc-unwrapped might work? I'll try that out.

[alyssais]

Ah yes, that looks likely! Probably better to use rustc.unwrapped over rustc-unwrapped so overriding stays easy.

[alyssais]

clippy likely needs a similar fix

[Samyak2]

Yes, clippy wasn't working either.

Opened a PR to fix both: #274482

Thank you for the help!