bug: librewolf/firefox conflict

[pshirshov]

Are you following the right branch?

• My Nixpkgs and Home Manager versions are in sync

Is there an existing issue for this?

• I have searched the existing issues

Issue description

I have both firefox and librewolf enabled. Today I've started getting these errors while trying to build:

       error: The option `home-manager.users.pavel.home.file.".mozilla/native-messaging-hosts".source' has conflicting definition values:
       - In `/nix/store/q25mjcgjyxi94s00k0ga58kr8mgf7k36-source/modules/programs/firefox.nix': "/nix/store/35690bcv4943cc6x4a179qp2lilfh9ki-ff_native-messaging-hosts/lib/mozilla/native-messaging-hosts"
       - In `/nix/store/q25mjcgjyxi94s00k0ga58kr8mgf7k36-source/modules/programs/librewolf.nix': "/nix/store/my71xvg12m1kqmssh1l6n71jxj0glyq0-ff_native-messaging-hosts/lib/mozilla/native-messaging-hosts"
       Use `lib.mkForce value` or `lib.mkDefault value` to change the priority on any of these definitions.

It seems to be a regression, am I correct?

Maintainer CC

No response

System information

❯ nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.12.10, NixOS, 25.05 (Warbler), 25.05.20250216.9c88845`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.24.11`
 - nixpkgs: `/nix/store/yd3115wbicrgm18qw6h6dmmv5zywzyk1-source`

[booxter]

You are broken by #6421

The fix is directionally correct (both apps use the same directory), but breaks when both apps are configured. This issue is very similar to what I'm trying to fix in #6460 (where I had conflict between thunderbird and firefox), but more work on top of it would be needed to allow multiple firefox derivatives at the same time.

@khaneliman I wonder... should the offending PR be reverted until my PR that merges native hosts for all apps into one directory is merged and adopted for librewolf etc.?

[khaneliman]

Ugh... this firefox nightmare. Yeah, we need to overhaul these to properly support multiple usages.

[Mikilio]

What if we just merge the configurations in all definitions in a hidden option.
Or just make native messenger configuration global instead of derivative specific.

[booxter]

@Mikilio this is kinda what I do in my patch (for thunderbird vs firefox; on Linux they use the same directory). This will have to extend to other firefox derivatives. (for these - I think also on MacOS).

[brckd]

Sometimes I regret splitting the Firefox derivations into separate modules 😅 As you said, this option should probably be merged. A configurable option alias could be a fix that works with the current setup.

[booxter]

I believe the issue was actually already fixed by #6460 ; I sent a patch that adds a test case to confirm it, but I see locally it passes already (and fails if I revert my merged PR). So please retry with the latest and confirm. @pshirshov

[khaneliman]

I believe the issue was actually already fixed by #6460 ; I sent a patch that adds a test case to confirm it, but I see locally it passes already (and fails if I revert my merged PR). So please retry with the latest and confirm. @pshirshov

That's what I was hoping while we were working through that. They should be using the shared option now.