stdenv: fix propagatedUserEnvPkgs when __structuredAttrs is true again

[jian-lin]

This is a follow-up of #388908.

Previously, $out/nix-support/propagated-user-env-packages was not created when __structuredAttrs was enabled, the first element of propagatedUserEnvPkgs was null and the length of propagatedUserEnvPkgs was at least 2.

Fixes #388829

With this patch applied, condition check result for each propagatedUserEnvPkgs is shown below.

propagatedUserEnvPkgs	__structuredAttrs enabled	__structuredAttrs disabled
null	false	false
[ ]	false	false
[ null ]	false	false
[ null "foo" ]	true ( previously was false)	true

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[ShamrockLee]

The setup.sh change looks good.

[wolfgangwalther]

Ah, I even thought about this part in the fir PR - but then assumed that "nobody is going to pass an empty string as the first pkg anyway, so it should be fine". Didn't think about null.

[RossComputerGuy]

LGTM

[ShamrockLee]

To err on the safe side before merging, has anyone built and confirmed that it works?

I originally planned to test it tonight, but my tablet is temporarily unavailable.

[RossComputerGuy]

What attribute do you want tested? I'll spin up a build on my Ampere system at home.

[ShamrockLee]

What attribute do you want tested?

I would like to see if

pkgs.hello.overrideAttrs { __structuredAttrs = true; propagatedUserEnvPkgs = [ null pkgs.bash ]; }

built output produces the correct $out/nix-support/propagated-user-env-packages file.

I would be curious about the result for [ null null pkgs.bash ] and [ null null ] as well.

I'll spin up a build on my Ampere system at home.

Thanks a lot!

[RossComputerGuy]

I would like to see if

pkgs.hello.overrideAttrs { __structuredAttrs = true; propagatedUserEnvPkgs = [ null pkgs.bash ]; }

built output produces the correct $out/nix-support/propagated-user-env-packages file.

I would be curious about the result for [ null null pkgs.bash ] and [ null null ] as well.

Ok it built and only has bash interactive in it.

 /nix/store/63j885krhx6yc0dv8z5z5csg97ihz7hy-bash-interactive-5.2p37

[ShamrockLee]

I know little about Emacs and its plugins.

Nevertheless, since stdenv's setup.sh works as expected, plut two other approavals, it should be safe to merge.