Add Upgrading from Tailwind CSS v… when running upgrade tool
#19026
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
thecrypticace
approved these changes
Sep 29, 2025
RobinMalfait
added a commit
that referenced
this pull request
Sep 29, 2025
This PR fixes an issue where sometimes people try to run the upgrade tool, reset the changes and then try again. If this happens, then the `package.json` and/or your lock file will point to the old Tailwind CSS v3 version, but the actual installed version will be v4. This will also cause the upgrade tool to now upgrade from v4 to v4, which is not what most people want if they were trying to upgrade from v3 to v4. This in turn will cause some issues because now we won't try to migrate the config file, or v3-specific classes that also exist in v4 but are only safe to upgrade from v3 to v4. This PR uses `npm ls tailwindcss` to determine the actual installed version. This command already errors if there is a mismatch between the installed version and the version in `package.json` or the lock file. This also happens to work in pnpm and bun projects (added integration tests for these). If for whatever reason we can't determine the expected version, we fall back to the old behavior of just upgrading. In this scenario, the changes introduced in #19026 will at least give you a hint of what version was actually installed. ### Test plan 1. Tested it in a v3 project where I performed the following steps: 1. Run the upgrade tool in full (`npx tailwindcss-upgrade`) 2. Reset the changes (`git reset --hard && git clean -df`) 1. Run the upgrade tool again This resulted in the following output: <img width="1059" height="683" alt="image" src="https://github.com/user-attachments/assets/1d2ea2d1-b602-4631-958f-cc21eb8a633f" /> 2. Added some integration tests to make sure this also works in pnpm, bun and normal npm projects. [ci-all]
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This PR adds a bit more information when running the upgrade tool to know what version of Tailwind CSS you're upgrading from. This will help users and maintainers when things go wrong.
Will have another PR up soon that errors when the Tailwind CSS version in package.json and node_modules don't match.
Test plan
Ran this one one of our older projects and saw the version logged correctly.