Show version mismatch when running upgrade tool #19028

RobinMalfait · 2025-09-29T11:29:31Z

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

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)
3. Run the upgrade tool again
This resulted in the following output:
Added some integration tests to make sure this also works in pnpm, bun and normal npm projects.

[ci-all]

RobinMalfait · 2025-09-29T12:23:45Z

packages/@tailwindcss-upgrade/src/index.ts

+    error(
+      [
+        'Version mismatch',
+        '',
+        pc.dim('```diff'),
+        `${pc.red('-')} ${`${pc.dim('"tailwindcss":')} ${`${pc.dim('"')}${pc.blue(version.expectedTailwindVersion(base))}${pc.dim('"')}`}`} (expected version in package.json / lockfile)`,
+        `${pc.green('+')} ${`${pc.dim('"tailwindcss":')} ${`${pc.dim('"')}${pc.blue(version.installedTailwindVersion(base))}${pc.dim('"')}`}`} (installed version in \`node_modules\`)`,
+        pc.dim('```'),
+        '',
+        `Make sure to run ${highlight(`${pkgManager} install`)}, and try again.`,
+      ].join('\n'),
+      {
+        prefix: '↳ ',
+      },
+    )


Open to suggestions here!

I think i would say "Tailwind CSS version mismatch" but other than that this seems fine to me.

aside: I don't think it needs to change since tailwindcss is also prevent in the diff so if you don't wanna change it that's fine imo. 🤷‍♂️

I think this is a good change if we want to show more issues. But I used the '↳' as well because it's sort of a continuation of the previous Tailwind CSS version

When splitting `'foo\n\nbar'` by `\n`, you will get `['foo', '', 'bar']`. The `''` value will result in `[]` after the word wrapping. This information gets lost when we `flatMap`, so let's keep the newline using `['']` as the fallback.

This is used for some tests that interact with `git` and have to commit things during tests.

This PR contains the following updates: | Package | Change | Age | Confidence | |---|---|---|---| | [@tailwindcss/postcss](https://tailwindcss.com) ([source](https://github.com/tailwindlabs/tailwindcss/tree/HEAD/packages/@tailwindcss-postcss)) | [`4.1.12` -> `4.1.17`](https://renovatebot.com/diffs/npm/@tailwindcss%2fpostcss/4.1.12/4.1.17) | [![age](https://developer.mend.io/api/mc/badges/age/npm/@tailwindcss%2fpostcss/4.1.17?slim=true)](https://docs.renovatebot.com/merge-confidence/) | [![confidence](https://developer.mend.io/api/mc/badges/confidence/npm/@tailwindcss%2fpostcss/4.1.12/4.1.17?slim=true)](https://docs.renovatebot.com/merge-confidence/) | --- ### Release Notes <details> <summary>tailwindlabs/tailwindcss (@tailwindcss/postcss)</summary> ### [`v4.1.17`](https://github.com/tailwindlabs/tailwindcss/blob/HEAD/CHANGELOG.md#4117---2025-11-06) [Compare Source](tailwindlabs/tailwindcss@v4.1.16...v4.1.17) ##### Fixed - Substitute `@variant` inside legacy JS APIs ([#19263](tailwindlabs/tailwindcss#19263)) - Prevent occasional crash on Windows when loaded into a worker thread ([#19242](tailwindlabs/tailwindcss#19242)) ### [`v4.1.16`](https://github.com/tailwindlabs/tailwindcss/blob/HEAD/CHANGELOG.md#4116---2025-10-23) [Compare Source](tailwindlabs/tailwindcss@v4.1.15...v4.1.16) ##### Fixed - Discard candidates with an empty data type ([#19172](tailwindlabs/tailwindcss#19172)) - Fix canonicalization of arbitrary variants with attribute selectors ([#19176](tailwindlabs/tailwindcss#19176)) - Fix invalid colors due to nested `&` ([#19184](tailwindlabs/tailwindcss#19184)) - Improve canonicalization for `& > :pseudo` and `& :pseudo` arbitrary variants ([#19178](tailwindlabs/tailwindcss#19178)) ### [`v4.1.15`](https://github.com/tailwindlabs/tailwindcss/blob/HEAD/CHANGELOG.md#4115---2025-10-20) [Compare Source](tailwindlabs/tailwindcss@v4.1.14...v4.1.15) ##### Fixed - Fix Safari devtools rendering issue due to `color-mix` fallback ([#19069](tailwindlabs/tailwindcss#19069)) - Suppress Lightning CSS warnings about `:deep`, `:slotted`, and `:global` ([#19094](tailwindlabs/tailwindcss#19094)) - Fix resolving theme keys when starting with the name of another theme key in JS configs and plugins ([#19097](tailwindlabs/tailwindcss#19097)) - Allow named groups in combination with `not-*`, `has-*`, and `in-*` ([#19100](tailwindlabs/tailwindcss#19100)) - Prevent important utilities from affecting other utilities ([#19110](tailwindlabs/tailwindcss#19110)) - Don’t index into strings with the `theme(…)` function ([#19111](tailwindlabs/tailwindcss#19111)) - Fix parsing issue when `\t` is used in at-rules ([#19130](tailwindlabs/tailwindcss#19130)) - Upgrade: Canonicalize utilities containing `0` values ([#19095](tailwindlabs/tailwindcss#19095)) - Upgrade: Migrate deprecated `break-words` to `wrap-break-word` ([#19157](tailwindlabs/tailwindcss#19157)) ##### Changed - Remove the `postinstall` script from oxide (\[[#19149](https://github.com/tailwindlabs/tailwindcss/issues/19149)])([#19149](https://github.com/tailwindlabs/tailwindcss/pull/19149)) ### [`v4.1.14`](https://github.com/tailwindlabs/tailwindcss/blob/HEAD/CHANGELOG.md#4114---2025-10-01) [Compare Source](tailwindlabs/tailwindcss@v4.1.13...v4.1.14) ##### Fixed - Handle `'` syntax in ClojureScript when extracting classes ([#18888](tailwindlabs/tailwindcss#18888)) - Handle `@variant` inside `@custom-variant` ([#18885](tailwindlabs/tailwindcss#18885)) - Merge suggestions when using `@utility` ([#18900](tailwindlabs/tailwindcss#18900)) - Ensure that file system watchers created when using the CLI are always cleaned up ([#18905](tailwindlabs/tailwindcss#18905)) - Do not generate `grid-column` utilities when configuring `grid-column-start` or `grid-column-end` ([#18907](tailwindlabs/tailwindcss#18907)) - Do not generate `grid-row` utilities when configuring `grid-row-start` or `grid-row-end` ([#18907](tailwindlabs/tailwindcss#18907)) - Prevent duplicate CSS when overwriting a static utility with a theme key ([#18056](tailwindlabs/tailwindcss#18056)) - Show Lightning CSS warnings (if any) when optimizing/minifying ([#18918](tailwindlabs/tailwindcss#18918)) - Use `default` export condition for `@tailwindcss/vite` ([#18948](tailwindlabs/tailwindcss#18948)) - Re-throw errors from PostCSS nodes ([#18373](tailwindlabs/tailwindcss#18373)) - Detect classes in markdown inline directives ([#18967](tailwindlabs/tailwindcss#18967)) - Ensure files with only `@theme` produce no output when built ([#18979](tailwindlabs/tailwindcss#18979)) - Support Maud templates when extracting classes ([#18988](tailwindlabs/tailwindcss#18988)) - Upgrade: Do not migrate `variant = 'outline'` during upgrades ([#18922](tailwindlabs/tailwindcss#18922)) - Upgrade: Show version mismatch (if any) when running upgrade tool ([#19028](tailwindlabs/tailwindcss#19028)) - Upgrade: Ensure first class inside `className` is migrated ([#19031](tailwindlabs/tailwindcss#19031)) - Upgrade: Migrate classes inside `*ClassName` and `*Class` attributes ([#19031](tailwindlabs/tailwindcss#19031)) ### [`v4.1.13`](https://github.com/tailwindlabs/tailwindcss/blob/HEAD/CHANGELOG.md#4113---2025-09-03) [Compare Source](tailwindlabs/tailwindcss@v4.1.12...v4.1.13) ##### Changed - Drop warning from browser build ([#18731](tailwindlabs/tailwindcss#18731)) - Drop exact duplicate declarations when emitting CSS ([#18809](tailwindlabs/tailwindcss#18809)) ##### Fixed - Don't transition `visibility` when using `transition` ([#18795](tailwindlabs/tailwindcss#18795)) - Discard matched variants with unknown named values ([#18799](tailwindlabs/tailwindcss#18799)) - Discard matched variants with non-string values ([#18799](tailwindlabs/tailwindcss#18799)) - Show suggestions for known `matchVariant` values ([#18798](tailwindlabs/tailwindcss#18798)) - Replace deprecated `clip` with `clip-path` in `sr-only` ([#18769](tailwindlabs/tailwindcss#18769)) - Hide internal fields from completions in `matchUtilities` ([#18820](tailwindlabs/tailwindcss#18820)) - Ignore `.vercel` folders by default (can be overridden by `@source …` rules) ([#18855](tailwindlabs/tailwindcss#18855)) - Consider variants starting with `@-` to be invalid (e.g. `@-2xl:flex`) ([#18869](tailwindlabs/tailwindcss#18869)) - Do not allow custom variants to start or end with a `-` or `_` ([#18867](tailwindlabs/tailwindcss#18867), [#18872](tailwindlabs/tailwindcss#18872)) - Upgrade: Migrate `aria` theme keys to `@custom-variant` ([#18815](tailwindlabs/tailwindcss#18815)) - Upgrade: Migrate `data` theme keys to `@custom-variant` ([#18816](tailwindlabs/tailwindcss#18816)) - Upgrade: Migrate `supports` theme keys to `@custom-variant` ([#18817](tailwindlabs/tailwindcss#18817)) </details> --- ### Configuration 📅 **Schedule**: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined). 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Renovate Bot](https://github.com/renovatebot/renovate).  Reviewed-on: https://git.in.csmpro.ru/csmpro/csm-mapban/pulls/28 Co-authored-by: Renovate Bot <renovate@csmpro.ru> Co-committed-by: Renovate Bot <renovate@csmpro.ru>

RobinMalfait marked this pull request as ready for review September 29, 2025 11:32

RobinMalfait requested a review from a team as a code owner September 29, 2025 11:32

RobinMalfait commented Sep 29, 2025

View reviewed changes

thecrypticace approved these changes Sep 29, 2025

View reviewed changes

Base automatically changed from fix/show-upgrading-from-version to main September 29, 2025 13:59

RobinMalfait added 8 commits September 29, 2025 16:00

ensure \n\n are kept as \n\n

357221d

When splitting `'foo\n\nbar'` by `\n`, you will get `['foo', '', 'bar']`. The `''` value will result in `[]` after the word wrapping. This information gets lost when we `flatMap`, so let's keep the newline using `['']` as the fallback.

add expected Tailwind CSS version

ab7dda1

error when there is a version mismatch

294fa85

add integration tests for pnpm, npm and bun

c9dd535

update changelog

f53cd0a

setup git config in CI

c9537f0

This is used for some tests that interact with `git` and have to commit things during tests.

set config globally

ac36a04

strip VTControl characters to make CI happy

11e1d71

RobinMalfait force-pushed the feat/error-on-version-mismatch branch from eef6bd8 to 11e1d71 Compare September 29, 2025 14:00

RobinMalfait merged commit 9d00662 into main Sep 29, 2025
21 checks passed

RobinMalfait deleted the feat/error-on-version-mismatch branch September 29, 2025 14:21

This was referenced Oct 21, 2025

build(deps-dev): Bump tailwindcss from 4.1.13 to 4.1.15 blinklabs-io/utxorpc-example#240

Merged

chore(deps-dev): bump tailwindcss from 3.4.18 to 4.1.16 WhizUs-Labs/kcd-showcase-trw-demo-app#28

Closed

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

Uh oh!

Show version mismatch when running upgrade tool #19028

Show version mismatch when running upgrade tool #19028

Uh oh!

RobinMalfait commented Sep 29, 2025 •

edited

Loading

Uh oh!

RobinMalfait Sep 29, 2025 •

edited

Loading

Uh oh!

thecrypticace Sep 29, 2025

Uh oh!

thecrypticace Sep 29, 2025

Uh oh!

RobinMalfait Sep 29, 2025

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

Uh oh!

Show version mismatch when running upgrade tool #19028

Show version mismatch when running upgrade tool #19028

Uh oh!

Conversation

RobinMalfait commented Sep 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Test plan

Uh oh!

RobinMalfait Sep 29, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Choose a reason for hiding this comment

Uh oh!

thecrypticace Sep 29, 2025

Choose a reason for hiding this comment

Uh oh!

thecrypticace Sep 29, 2025

Choose a reason for hiding this comment

Uh oh!

RobinMalfait Sep 29, 2025

Choose a reason for hiding this comment

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

3 participants

RobinMalfait commented Sep 29, 2025 •

edited

Loading

RobinMalfait Sep 29, 2025 •

edited

Loading