Error running tests on x86_64-darwin **only on CI**

[Radvendii]

Describe the bug

I've been trying to build nix in CI as a dependency for a nickel experimental feature, and am getting an error on the foldlPrime test on the x86_64-darwin builder. When I try to reproduce it on my local x86_64-darwin machine, there is no error.

• Both are using nix 2.17.0.
• The derivations in both cases are identical (i checked not only the store path but the contents).
• This error has happened on multiple versions of Nix (i.e. i tried to update and that didn't fix it)

CI logs: https://github.com/tweag/nickel/actions/runs/6427208299/job/17452514550?pr=1465#step:5:4453

Relevant part:

nix> src/libexpr/tests/error_traces.cc:758: Failure
nix> Expected equality of these values:
nix>   e.info().traces.size()
nix>     Which is: 3
nix>   2
nix> while testing foldl' (a: b: a && b) "foo" [ true ]
nix> error:
nix>        … while calling the 'foldl'' builtin
nix>          at «string»:1:1:
nix>             1| builtins.foldl' (a: b: a && b) "foo" [ true ]
nix>              | ^
nix>        … while calling anonymous lambda
nix>          at «string»:1:21:
nix>             1| builtins.foldl' (a: b: a && b) "foo" [ true ]
nix>              |                     ^
nix>        error: value is a string while a Boolean was expected
nix> [  FAILED  ] ErrorTraceTest.foldlPrime (0 ms)

The error trace produced on my local machine, which matches what the test expects, is:

error:
        … while calling the 'foldl'' builtin
          at «string»:1:1:
             1| builtins.foldl' (a: b: a && b) "foo" [ true ]
              | ^
        … in the left operand of the AND (&&) operator
          at «string»:1:21:
             1| builtins.foldl' (a: b: a && b) "foo" [ true ]
              |                     ^
        error: value is a string while a Boolean was expected

Expected behavior

The tests should pass. But perhaps more concerning, nix builds should produce consistent results across different machines.

nix-env --version output

nix-env (Nix) 2.17.0 on both

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