I just started noticing this error yesterday and was trying to debug it when someone else reported it in Zulip

Notice: Undefined index: base in _color_rewrite_stylesheet() (line 691 of /app/src/core/modules/color/color.module).

It seems like this error messages started appearing after the most recent core update and @joseph_flatt speculated the following:

I think that the issue is happening more because of the change so that we regenerate color files when clearing caches. The error is coming from the fact that the color module requires that one of the color sets is named 'base', and then it generates it every time the files are regenerated.

You should try commenting out the 'blend_target' setting from your color.inc. We made color blending optional in a release a while back, and the color blending is what is looking for fields with a specific name.


I was having this problem with the Tatsu theme. After removing the 'blend_target' from the color.inc file, the problem went away.

Is this a core issue or just something that folks need to update in their themes?

klonos's picture

I'd say it's a core bug, so we should have an issue in GitHub for it.

Hey guys...

Just noticed this error, not exactly the same as the one reported here but I'd say it's close enough.

Notice: Undefined index: bg in _color_rewrite_stylesheet() (line 690 of /app/domain/public_html/core/modules/color/color.module).

Can somebody plaese point me in the right direction...?

Warm regards.