Release X.Y (202?-??-??)

  • A new function builtins.readFileType is available. It is similar to builtins.readDir but acts on a single file or directory.

  • The builtins.readDir function has been optimized when encountering not-yet-known file types from POSIX's readdir. In such cases the type of each file is/was discovered by making multiple syscalls. This change makes these operations lazy such that these lookups will only be performed if the attribute is used. This optimization affects a minority of filesystems and operating systems.

  • In derivations that use structured attributes, you can now use unsafeDiscardReferences to disable scanning a given output for runtime dependencies:

    __structuredAttrs = true;
    unsafeDiscardReferences.out = true;
    

    This is useful e.g. when generating self-contained filesystem images with their own embedded Nix store: hashes found inside such an image refer to the embedded store and not to the host's Nix store.

    This requires the discard-references experimental feature.