Hello folks, I want to PR darwin support for libtree (analysis of linked libraries) and I have questions about tests.

There's a passthru.tests attrset at https://github.com/NixOS/nixpkgs/blob/5e2a59a5b1a82f89f2c7e598302a9cacebb72a67/pkgs/by-name/li/libtree/package.nix#L28-L46 which tests ls from coreutils. On macos, by default, it checks the macOS build of ls, which is not an ELF. I can get it to work properly using pkgsCross, as in the following.

    (libtree.override {
      inherit (pkgsCross.aarch64-multiplatform) coreutils;
    }).overrideAttrs
      (old: {
        meta = lib.recursiveUpdate (old.meta or { }) { platforms = lib.platforms.darwin; };
      })

I presume that in this case libtree should always test the pkgsCross coreutils… but certainly the tests fail on macos without it. What's the idiomatic way of handling this case?

Hello folks, I want to PR darwin support for libtree (analysis of linked libraries) and I have questions about tests.

There's a passthru.tests attrset at https://github.com/NixOS/nixpkgs/blob/5e2a59a5b1a82f89f2c7e598302a9cacebb72a67/pkgs/by-name/li/libtree/package.nix#L28-L46 which tests ls from coreutils. On macos, by default, it checks the macOS build of ls, which is not an ELF. I can get it to work properly using pkgsCross, as in the following.

    (libtree.override {
      inherit (pkgsCross.aarch64-multiplatform) coreutils;
    }).overrideAttrs
      (old: {
        meta = lib.recursiveUpdate (old.meta or { }) { platforms = lib.platforms.darwin; };
      })

I presume that in this case libtree should always test the pkgsCross coreutils… but certainly the tests fail on macos without it. What's the idiomatic way of handling this case?

[Edit: I don't mean idiomatic way of implementing the changes, as opposed to the override, I mean the idiomatic way of handling the cross-platform dependency in the tests.]

Yes. There’s an open issue for Mach-O support, but it’s old.

https://github.com/haampie/libtree/issues/22

> nix build -L '.#libtree.tests.checkCoreUtils' --no-link --print-out-paths
/nix/store/40xm11r0sklkl4x5cp8xdckp5sha0yfd-libtree-ls-test

> nix build -L '.#libtree.tests.checkCoreUtils' --no-link --print-out-paths | xargs bat
───────┬──────────────────────────────────────────────────────────────────────────────────────────────
       │ File: /nix/store/40xm11r0sklkl4x5cp8xdckp5sha0yfd-libtree-ls-test
───────┼──────────────────────────────────────────────────────────────────────────────────────────────
   1   │ /nix/store/x2s54dnz7kd4vbslfcv1x3g69p30fz7y-coreutils-aarch64-unknown-linux-gnu-9.7/bin/ls
   2   │ ├── libacl.so.1 [runpath]
   3   │ │   └── libattr.so.1 [runpath]
   4   │ ├── libattr.so.1 [runpath]
   5   │ └── libgmp.so.10 [runpath]
───────┴──────────────────────────────────────────────────────────────────────────────────────────────

> nix build -L '.#libtree.tests.checkCoreUtils' --no-link --print-out-paths
/nix/store/40xm11r0sklkl4x5cp8xdckp5sha0yfd-libtree-ls-test

> nix build -L '.#libtree.tests.checkCoreUtils' --no-link --print-out-paths | xargs bat
───────┬──────────────────────────────────────────────────────────────────────────────────────────────
       │ File: /nix/store/40xm11r0sklkl4x5cp8xdckp5sha0yfd-libtree-ls-test
───────┼──────────────────────────────────────────────────────────────────────────────────────────────
   1   │ /nix/store/x2s54dnz7kd4vbslfcv1x3g69p30fz7y-coreutils-aarch64-unknown-linux-gnu-9.7/bin/ls
   2   │ ├── libacl.so.1 [runpath]
   3   │ │   └── libattr.so.1 [runpath]
   4   │ ├── libattr.so.1 [runpath]
   5   │ └── libgmp.so.10 [runpath]
───────┴──────────────────────────────────────────────────────────────────────────────────────────────

This is the test result, making the above change to use the pkgsCross (but not pkgsStatic!) coreutils.