matrix-synapse: move setuptools-rust back to build-system

[NickCao]

Things done

Per https://github.com/element-hq/synapse/blob/27223a349c0cb5268782dc07b20f3450580165dc/pyproject.toml#L87, setuptools-rust, despite being in dependencies, should actually be in build-system. And this is causing build failure of synapse plugins.

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

[NickCao]

Oops, this is causing runtime error.

[NickCao]

Oops, this is causing runtime error.

Fixed

[transcaffeine]

Thank you for getting it to work again! What was the missing piece to fix the runtime error (i.e. why does your change work)?

[yuyuyureka]

Likely this diff: https://github.com/NixOS/nixpkgs/compare/4794bc3b311adf92b6dcae01fb1269a12f855034..222f131923003c991dc47b190acf0d34a56baaf6

[teutat3s]

nixpkgs-review result

Generated using nixpkgs-review.

Command: nixpkgs-review pr 481373 --package matrix-synapse --package nixosTests.matrix-synapse
Commit: 222f131923003c991dc47b190acf0d34a56baaf6

---

aarch64-linux

✅ 1 test built:

• nixosTests.matrix-synapse

✅ 1 package built:

• matrix-synapse

[nixpkgs-ci]

Successfully created backport PR for release-25.11:

• [Backport release-25.11] matrix-synapse: move setuptools-rust back to build-system #481773