NPV 167

NPV-167: __structuredAttrs must not regress from true to false

Description

__structuredAttrs defines how derivation attributes are passed to the builder. It should evaluate to true for all new packages, and once it evaluates to true, it should not regress.

For more information on __structuredAttrs, see https://github.com/nixos/nixpkgs/blob/master/doc/stdenv/stdenv.chapter.md#__structuredattrs-var-stdenv-__structuredattrs.

Error message

- Attribute `pkgs.{package_name}` previously evaluated with `__structuredAttrs = true`, but now evaluates with `__structuredAttrs = false`.
  Please re-enable `__structuredAttrs = true;` in {file}.