The auto-upgrade tool (`@tailwindcss/upgrade`) doesn't work if the config contains any `future` settings

[simon-abbott]

What version of Tailwind CSS are you using?

v3.4.18

What build tool (or framework if it abstracts the build tool) are you using?

Not relevant

What version of Node.js are you using?

For example: v24.11.1

What browser are you using?

Not relevant

What operating system are you using?

macOS

Reproduction URL

https://play.tailwindcss.com/h0kWs7K0AO?file=config

Describe your issue

I am trying to upgrade from v3 to v4 using the auto-upgrade tool. To make this easier we have been using some future settings for a while now. But for reasons that I can't quite understand, running npx @tailwindcss/upgrade with any future options (even an empty object) breaks the auto migration of the config file. I would expect that the upgrade tool would know which future options have been implemented and would be able to auto-migrate them, but instead it looks like I am going to have to manually cross-reference each of these options to see if they have made it in.

[thecrypticace]

You should be able to remove the future key entirely and the upgrade should proceed normally.

• hoverOnlyWhenSupported: The default hover variant in v4 is closely equivalent to this
• disableColorOpacityUtilitiesByDefault: The color opacity utilities no longer exist in v4.
• relativeContentPathsByDefault: This is how content paths are resolved in v4.
• respectDefaultRingColorOpacity: You can define a --default-ring-color in the v4 theme for this. I don't think the upgrade tool handles this though. Something we need to fix.

[thecrypticace]

This will be fixed in the next release 👍