Assertion failure

Description:

$ nix build github:nix-community/nurl/7f789ea2da9ff52724efb38df01ecda87704fc87
/usr/include/c++/13.2.1/bits/unique_ptr.h:453: typename std::add_lvalue_reference<_Tp>::type std::unique_ptr<_Tp, _Dp>::operator*() const [with _Tp = git_tree_entry; _Dp = nix::Deleter<git_tree_entry_free>; typename std::add_lvalue_reference<_Tp>::type = git_tree_entry&]: Assertion 'get() != pointer()' failed.
fish: Job 1, 'nix build github:nix-community/…' terminated by signal SIGABRT (Abort)

Additional info:

• package version(s):

  • nix 2.20.3-1

• config and/or log files:

  • /etc/nix/nix.conf:

    build-users-group = nixbld
    auto-optimise-store = true
    extra-platforms = aarch64-linux i686-linux
    extra-experimental-features = auto-allocate-uids
    auto-allocate-uids = true

  • ~/.config/nix/nix.conf:

    experimental-features = nix-command flakes
    max-jobs = auto
    use-xdg-base-directories = true
    warn-dirty = false
    extra-nix-path = nixpkgs=flake:nixpkgs

• Backtrace:

  gdb.txt

Steps to reproduce:

1. $ nix build github:nix-community/nurl/7f789ea2da9ff52724efb38df01ecda87704fc87

Note that I was not able to reproduce this issue with the upstream version of nix, even on the same commit:

$ nix run github:NixOS/nix/8a8172cd2b5ef2f6dd2d9673a6379447d780ff17 build github:nix-community/nurl/7f789ea2da9ff52724efb38df01ecda87704fc87

works just fine. That is why I am reporting this issue here.