preventing rebuilds

[qaristote]

Often when I update my system the theme generated by stylix gets rebuilt as well. This is expected behavior, I assume it happens either because GHC was updated or because the palette-generator code changed (I update stylix frequently).

This is a bit inconvenient, as palette-generator takes a little while to generate a new theme, which is of course useless because it always happen to be the same as the previous one. So I was wondering if there were a way to tell NixOS to not rebuild the stylix-generated theme, or at least the palette-generator package (I assume the theme's only dependency is palette-generator). Is there a standard way to do this?

[trueNAHO]

Often when I update my system the theme generated by stylix gets rebuilt as well. This is expected behavior, I assume it happens either because GHC was updated or because the palette-generator code changed (I update stylix frequently).

[...]

So I was wondering if there were a way to tell NixOS to not rebuild the stylix-generated theme, or at least the palette-generator package (I assume the theme's only dependency is palette-generator). Is there a standard way to do this?

AFAIK, the following snippet is responsible for caching the palette:

stylix/stylix/palette.nix

Lines 169 to 193 in c5f8f06

	stylix.generated.fileTree = {
	# Making palette.json part of the system closure will protect it from
	# garbage collection, so future configurations can be evaluated without
	# having to generate the palette again. The generator is not kept, only
	# the palette which came from it, so this uses very little disk space.
	# The extra indirection should prevent the palette generator from running
	# when the theme is manually specified. generated.json is necessary in
	# the presence of overrides.
	"stylix/generated.json".source = config.lib.stylix.scheme {
	template = ./palette.json.mustache;
	extension = ".json";
	};
	"stylix/palette.json".source = config.lib.stylix.colors {
	template = ./palette.json.mustache;
	extension = ".json";
	};
	# We also provide a HTML version which is useful for viewing the colors
	# during development.
	"stylix/palette.html".source = config.lib.stylix.colors {
	template = ./palette.html.mustache;
	extension = ".html";
	};
	};

TBH, I am not entirely sure how palette-generator is actually cached. @danth might know more about this.

This is a bit inconvenient, as palette-generator takes a little while to generate a new theme

Based on the discussion from #477 it might be necessary to rewrite the palette generator in the future. Later, it might be possible to improve the palette generator performance.

[danth]

It seems that at some point this code was changed to generate the file through config.lib.stylix.colors rather than exporting generatedJSON directly. That will have broken the caching behaviour. The intention was to make the generatedJSON derivation part of the final system so it can't be garbage collected between evaluations.

[qaristote]

I ended up setting stylix.base16scheme to the value I found in /etc/stylix/generated.json.