How to override `buildFeatures` in Rust package

Help
1

I am trying to enable the experimental lessopen feature in bat in an overlay, but nothing I try works and I cannot find any information anywhere on what else to try.

I have tried:

final: prev: {
  bat = prev.bat.overrideAttrs (oldAttrs: {
    buildFeatures = (oldAttrs.buildFeatures or [ ]) ++ [ "lessopen" ];
  }
}

and

final: prev: {
  bat = prev.bat.overrideAttrs (oldAttrs: {
    cargoDeps = oldAttrs.cargoDeps.overrideAttrs (_: {
      buildFeatures = (oldAttrs.buildFeatures or [ ]) ++ [ "lessopen" ];
  });
}

but it does not seem to change anything.

When I try invalidating the hash like this:

final: prev: {
  bat = prev.bat.overrideAttrs (oldAttrs: {
    cargoDeps = oldAttrs.cargoDeps.overrideAttrs (_: {
      buildFeatures = (oldAttrs.buildFeatures or [ ]) ++ [ "lessopen" ];
      outputHash = "sha256-AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA=";
    });
  });
}

I just get the same hash as the vanilla bat package.

2

After messing around with it on and off and finally discovering this post that pointed me towards looking at the source code for buildRustPackage, I discovered that the attribute I needed to override was cargoBuildFeatures, not buildFeatures.

I was able to enable bat’s lessopen feature with this:

final: prev: {
  bat = prev.bat.overrideAttrs (oldAttrs: {
    cargoBuildFeatures = (oldAttrs.cargoBuildFeatures or [ ]) ++ [ "lessopen" ];
  });
}