chromium: (cross) invoke ungoogled-chromium via buildPackages

[ghost]

Description of changes

What we call ungoogled-chromium is, contrary to its name, not a build of chromium. It is a copy of chromium's source code upon which patchShebangs has already been performed. Therefore it needs to come from buildPackages, because it contains python scripts which get /nix/store/.../bin/python3 patched into their shebangs.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• 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/)
• 23.05 Release Notes (or backporting 22.11 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.

[ghost]

Alright, this project will need to wait until after ZHF.

[michaeladler]

Thanks, while the title accurately describes what you did, it's not immediately obvious to me what problem it actually solves. Is cross-compilation broken currently and this is the fix?

[ghost]

Is cross-compilation broken currently and this is the fix?

It is one small part of the fix. I have one large PR (not yet submitted) and a bunch of smaller ones that can be reviewed (and potentially merged) separately from it.

Here are the smaller PRs; all draftified because I'm not going to have the big one done in time:

• chromium: (cross) take python3 from buildPackages #227707
• chromium: (cross) take gnChromium from buildPackages #227708
• chromium: (cross) invoke ungoogled-chromium via buildPackages #227710
• chromium: (cross) take llvmPackages from pkgsBuildTarget #227719
• chromium: (cross): use cc-wrapper-clang instead of bare clang #227720
• chromium: (cross) move bison and gperf to nativeBuildInputs #227722
• chromium: (cross) strip aarch64-linux-gnu- toolprefix only for native builds #227723

Edit: dammit, pasted the wrong list of PRs.

[ghost]

Is cross-compilation broken currently

Yes, very much so. Or rather I don't think nixpkgs' chromium ever did cross compile correctly.

it's not immediately obvious to me what problem it actually solves

Well, if you cherry-pick all the above PRs except this one and

nix build -f . -L pkgsCross.aarch64-multiplatform.ungoogled-chromium

on a non-aarch64 machine, you'll get a build failure when your non-aarch64 machine tries to execute a python script in ungoogled-chromium which had its shebang patched to something like

#!/nix/store/.....-aarch64-unknown-linux-gnu-python3.11/bin/python3
...

So basically it's trying to execute the aarch64 python binary on your build machine (which is not aarch64).

This is the fix for that one specific problem. There are many others (in chromium -- I think this is the only one in the ungoogled-chromium portion).

[ghost]

a bunch of smaller ones that can be reviewed (and potentially merged) separately from it.

The other reason I broke them up is in case this project creates problems down the line -- it will be easier to git-bisect.

[michaeladler]

Thanks for the clarification and great work! Cross-compilation (aarch64) will become increasingly more important.

So basically it's trying to execute the aarch64 python binary on your build machine (which is not aarch64).

Yeah, that's what I thought but just wanted to make sure I got it :)

[ghost]

Included in #229265