Backgrounds not merging properly on Tailwind v4 + tailwind-merge v3

[AlanMorel]

Describe the bug

Backgrounds not merging properly on Tailwind v4 + tailwind-merge v3

To Reproduce

const before = "bg-black/15 bg-linear-to-b";
const after = twMerge(before);

console.log("before", before);
console.log("after", after);

I get

before bg-black/15 bg-linear-to-b
after bg-linear-to-b

Expected behavior

before bg-black/15 bg-linear-to-b
after bg-black/15 bg-linear-to-b

These two Tailwind classes can be used together. It worked when I was on Tailwind v3 + tailwinnd-merge v2, and it works when I manually add the class back.

Environment

"tailwind-merge": "^3.0.1",
"tailwindcss": "^4.0.1",

[dcastil]

Hey @AlanMorel! 👋

Just tried to reproduce your case locally and in CodeSandbox: https://codesandbox.io/p/sandbox/vnwq59?file=%2Fsrc%2Findex.ts%3A11%2C2.

In both cases I get back the string bg-black/15 bg-linear-to-b after merging. Is this the twMerge function exported from tailwind-merge or did you configure it with extendTailwindMerge?

[AlanMorel]

Hey Dany, I resolved my issue by just deleting my node_modules folder and reinstalling everything. I guess it might have still been using the old version somehow, leading to my original issue. Everything is good now on my end, apologies if I wasted your time.

Thanks so much!

[dcastil]

Ah good that it wasn't a bug in the package. No worries, this also happens to me from time to time. 😁