bup: allow disabling web support; disable on aarch64-darwin due to #172397

[andrew-d]

Description of changes

Adds a new configuration flag that allows disabling web support in bup. This is enabled by default everywhere except aarch64-darwin, where it's disabled so that we're not affected by #172397. This should also unbreak stuff that depends on bup like git-annex, which I also tested along with another package fix that I'll submit shortly.

(note that I disabled this here, rather than doing something in tornado package, since bup will function just fine without tornado being installed as long as you don't try to run bup web, whereas the dependency on the tornado side comes from tornado -> twisted -> pyOpenSSL, which is harder to unwind since none of those are optional)

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/)
• 22.11 Release Notes (or backporting 22.05 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
  • (Release notes changes) Ran nixos/doc/manual/md-to-db.sh to update generated release notes
• Fits CONTRIBUTING.md.

[SuperSandro2000]

twisted only optionally depends on pyopenssl https://github.com/NixOS/nixpkgs/blob/staging-next/pkgs/development/python-modules/twisted/default.nix#L138

If this is fixed with #179844, then we don't need to do anything here. Can you check that?

---

Edit: I just checked this against staging-next and on linux there is no longer a pyopenssl dependency. So it is very likely that this is the same case on darwin and we don't need this PR at all.

[andrew-d]

@SuperSandro2000 - It's possible that I'm doing this wrong, but... I'm still seeing the evaluation error on staging-next, commit 33b3f97

$ nix build './#legacyPackages.aarch64-darwin.python3Packages.twisted'
error: Package ‘python3.10-pyopenssl-22.0.0’ in /nix/store/168rj5f62ajfsk1p75yjw8sxvxsqkgvs-source/pkgs/development/python-modules/pyopenssl/default.nix:73 is marked as broken, refusing to evaluate.

       a) To temporarily allow broken packages, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_BROKEN=1

        Note: For `nix shell`, `nix build`, `nix develop` or any other Nix 2.4+
        (Flake) command, `--impure` must be passed in order to read this
        environment variable.

       b) For `nixos-rebuild` you can set
         { nixpkgs.config.allowBroken = true; }
       in configuration.nix to override this.

       c) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
         { allowBroken = true; }
       to ~/.config/nixpkgs/config.nix.
(use '--show-trace' to show detailed location information)

[SuperSandro2000]

I was only looking at runtime packages. This means it is somewhere a checkInput only like here https://github.com/NixOS/nixpkgs/blob/master/pkgs/development/python-modules/twisted/default.nix#L122-L138

I would suggest to rather disable pyopenssl tests on darwin than this workaround here.

[andrew-d]

I would suggest to rather disable pyopenssl tests on darwin than this workaround here.

Do you mean removing pyopenssl from the checkInputs of twisted on aarch64-darwin? Something like this appears to work:

diff --git pkgs/development/python-modules/twisted/default.nix pkgs/development/python-modules/twisted/default.nix
index 59011ef1d64..9db5c7e3372 100644
--- pkgs/development/python-modules/twisted/default.nix
+++ pkgs/development/python-modules/twisted/default.nix
@@ -119,7 +119,7 @@ buildPythonPackage rec {
     pyhamcrest
   ]
   ++ passthru.optional-dependencies.conch
-  ++ passthru.optional-dependencies.tls;
+  ++ lib.optionals (!(stdenv.isDarwin && stdenv.isAarch64)) passthru.optional-dependencies.tls;
 
   checkPhase = ''
     export SOURCE_DATE_EPOCH=315532800

I can submit this as another PR, if you like that approach better?