Redundancy in Firefox extension settings code?

[musjj]

I'm trying to understand this part of this code:

home-manager/modules/programs/firefox/mkFirefoxModule.nix

Lines 1005 to 1015 in 12fa854

	(mkMerge (
	mapAttrsToList (
	name: settingConfig:
	mkIf (settingConfig.settings != { }) {
	"${cfg.profilesPath}/${profile.path}/browser-extension-data/${name}/storage.js" = {
	force = settingConfig.force || profile.extensions.force;
	text = lib.generators.toJSON { } settingConfig.settings;
	};
	}
	) profile.extensions.settings
	))

As far as I can tell, to set profile.extensions.settings.${addonId}.settings you also need to set profile.extensions.force to true, due to this assertion:

home-manager/modules/programs/firefox/mkFirefoxModule.nix

Lines 792 to 802 in 12fa854

	assertions = [
	(mkNoDuplicateAssertion config.containers "container")
	{
	assertion = !(extensionSettingsNeedForce config.extensions.settings) || config.extensions.force;
	message = ''
	Using '${lib.showOption profilePath}.extensions.settings' will override all
	previous extensions settings. Enable
	'${lib.showOption profilePath}.extensions.force' to acknowledge this.
	'';
	}
	]

So the settingConfig.force || profile.extensions.force above will practically always evaluate to true, regardless of the individual extension's force setting.

[khaneliman]

Yes, that reading is correct for the current implementation.

There are two related concepts here:

• profile.extensions.force is used as an explicit acknowledgement that Home Manager-managed extension storage can replace existing Firefox extension state.
• profile.extensions.settings.<addonId>.force looks like it was intended to allow that replacement decision per extension.

But because of this assertion:

assertion = !(extensionSettingsNeedForce config.extensions.settings) || config.extensions.force;

any non-empty extensions.settings.<addonId>.settings requires the profile-level extensions.force = true. Once that is true, this later expression:

force = settingConfig.force || profile.extensions.force;

will always evaluate to true for every generated browser-extension-data/<addonId>/storage.js file.

So in practice, the per-extension force option does not currently provide a narrower override for extension settings. It is effectively redundant for settings as long as the profile-level assertion remains as-is.

I think the likely fix would be one of these:

1. remove the per-extension force option if the intended behavior is profile-wide acknowledgement only, or
2. relax/change the assertion so that each extension with non-empty settings must have either its own force = true or the profile-level extensions.force = true.

The second option would make the existing option meaningful while preserving the acknowledgement requirement.

[khaneliman]

Created #9345 to address