This PR bumps the Prettier dependencies, and also pins the version.
Noticed that a PR with a single empty commit started failing at the time
of writing this
(https://github.com/tailwindlabs/tailwindcss/pull/16306). This is
because prettier released a new minor version which results in slightly
different output.
Let's bump prettier and handle the differences, but also pin the version
to avoid this in the future.
<!--
👋 Hey, thanks for your interest in contributing to Tailwind!
**Please ask first before starting work on any significant new
features.**
It's never a fun experience to have your pull request declined after
investing a lot of time and effort into a new feature. To avoid this
from happening, we request that contributors create an issue to first
discuss any significant new features. This includes things like adding
new utilities, creating new at-rules, or adding new component examples
to the documentation.
https://github.com/tailwindcss/tailwindcss/blob/master/.github/CONTRIBUTING.md
-->
---------
Co-authored-by: Adam Wathan <4323180+adamwathan@users.noreply.github.com>
Resolves#16170
This PR fixes an issue where the previously opted-out escaping of the
first argument for the `var(…)` function was not unescaped at all. This
was introduced in https://github.com/tailwindlabs/tailwindcss/pull/14776
where the intention was to not require escaping of underscores in the
var function (e.g. `ml-[var(--spacing-1_5)]`). However, I do think it
still makes sense to unescape an eventually escaped underline for
consistency.
## Test plan
The example from #1670 now parses as expected:
<img width="904" alt="Screenshot 2025-02-03 at 13 51 35"
src="https://github.com/user-attachments/assets/cac0f06e-37da-4dcb-a554-9606d144a8d5"
/>
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
This PR fixes the upgrade tool by properly migrating the
`leading-[<number>]` classes.
The issue is that `leading-[<number>]` maps to the number directly, but
if you use a bare value, then it's a multiplier for based on the
`--spacing` value.
E.g.:
*leading-[2]*:
```css
.leading-\[2\] {
--tw-leading: 2;
line-height: 2;
}
@property --tw-leading {
syntax: "*";
inherits: false;
}
```
*leading-2*:
```css
.leading-2 {
--tw-leading: calc(var(--spacing) * 2);
line-height: calc(var(--spacing) * 2);
}
@property --tw-leading {
syntax: "*";
inherits: false;
}
```
This PR will now prevent migrating arbitrary values to bare values for
`leading-*` utilities.
That said, this does introduce a small improvement where `leading-[1]`
is migrated to `leading-none`.
Fixes: https://github.com/tailwindlabs/tailwindcss/issues/15924
Closes#15220
This PR fixes an issue where the upgrade tool would not be able to load
some JavaScript config files across different drive letters on Windows.
The issue in detail is that `path.relative(…)` tries to build a relative
path but if the file is inside the same folder, it won't start the
relative path with a `./` so we manually appended it in case that it
isn't there. The issue on Windows specifically is that
`file.relative(…)` can also return a legit absolute path, e.g. when the
file is on a different drive. In this case we obviously don't want to
prefix a path with `./`.
## Test plan
To reproduce this issue, I checked out a Tailwind v3 project _on a
different drive letter than my Windows installation_. In that case, I
was adding a repo inside `D:` while `npm` was installed in `C:`. I then
run `npx @tailwindcss/upgrade` to reproduce the issue.
The fix was validated with a local `bun` run of the upgrade tool:
This PR replaces `@variant` with `@custom-variant` for registering
custom variants via your CSS.
In addition, this PR introduces `@variant` that can be used in your CSS
to use a variant while writing custom CSS.
E.g.:
```css
.btn {
background: white;
@variant dark {
background: black;
}
}
```
Compiles to:
```css
.btn {
background: white;
}
@media (prefers-color-scheme: dark) {
.btn {
background: black;
}
}
```
For backwards compatibility, the `@variant` rules that don't have a body
and are
defined inline:
```css
@variant hocus (&:hover, &:focus);
```
And `@variant` rules that are defined with a body and a `@slot`:
```css
@variant hocus {
&:hover, &:focus {
@slot;
}
}
```
Will automatically be upgraded to `@custom-variant` internally, so no
breaking changes are introduced with this PR.
---
TODO:
- [x] ~~Decide whether we want to allow multiple variants and if so,
what syntax should be used. If not, nesting `@variant <variant> {}` will
be the way to go.~~ Only a single `@variant <variant>` can be used, if
you want to use multiple, nesting should be used:
```css
.foo {
@variant hover {
@variant focus {
color: red;
}
}
}
```
This PR improves the upgrade tool to make sure that newly upgraded
`--spacing(2)` CSS functions is pretty printed to prevent unambiguous
looking classes (even though it compiles correctly).
If you have a class such as `m-[calc(100dvh-theme(spacing.2))]`, then we
used to convert it to `m-[calc(100dvh-calc(var(--spacing)*2))]`. But
recently we introduced the `--spacing(2)` CSS function which means that
the output now looks like this instead: `m-[calc(100dvh---spacing(2))]`.
The triple `-` is valid because the first `-` is the minus sign, the
next two `-` characters are from the function.
One solution is to introduce spaces via underscores:
```
m-[calc(100dvh_-_--spacing(2))]
```
But a simpler solution, is to wrap the `--spacing(2)` in parens to
remove the underscores and improve the readability of the `---`
characters.
```
m-[calc(100dvh-(--spacing(2)))]
```
Here is everything you need to know about this update. Please take a
good look at what changed and the test results before merging this pull
request.
### What changed?
#### ✳️ prettier (3.3.3 → 3.4.2) ·
[Repo](https://github.com/prettier/prettier) ·
[Changelog](https://github.com/prettier/prettier/blob/main/CHANGELOG.md)
<details>
<summary>Release Notes</summary>
<h4><a
href="https://github.com/prettier/prettier/releases/tag/3.4.2">3.4.2</a></h4>
<blockquote><p dir="auto">🔗 <a
href="https://bounce.depfu.com/github.com/prettier/prettier/blob/main/CHANGELOG.md#342">Changelog</a></p></blockquote>
<h4><a
href="https://github.com/prettier/prettier/releases/tag/3.4.1">3.4.1</a></h4>
<blockquote><p dir="auto">🔗 <a
href="https://bounce.depfu.com/github.com/prettier/prettier/blob/main/CHANGELOG.md#341">Changelog</a></p></blockquote>
<p><em>Does any of this look wrong? <a
href="https://depfu.com/packages/npm/prettier/feedback">Please let us
know.</a></em></p>
</details>
<details>
<summary>Commits</summary>
<p><a
href="52829385bc...cca946176c">See
the full diff on Github</a>. The new version differs by more commits
than we can show here.</p>
</details>
---
[Depfu](https://depfu.com) will automatically keep this PR
conflict-free, as long as you don't add any commits to this branch
yourself. You can also trigger a rebase manually by commenting with
`@depfu rebase`.
<details><summary>All Depfu comment commands</summary>
<blockquote><dl>
<dt>@depfu rebase</dt><dd>Rebases against your default branch and
redoes this update</dd>
<dt>@depfu recreate</dt><dd>Recreates this PR, overwriting any edits
that you've made to it</dd>
<dt>@depfu merge</dt><dd>Merges this PR once your tests are passing and
conflicts are resolved</dd>
<dt>@depfu cancel merge</dt><dd>Cancels automatic merging of this
PR</dd>
<dt>@depfu close</dt><dd>Closes this PR and deletes the branch</dd>
<dt>@depfu reopen</dt><dd>Restores the branch and reopens this PR (if
it's closed)</dd>
<dt>@depfu pause</dt><dd>Ignores all future updates for this dependency
and closes this PR</dd>
<dt>@depfu pause [minor|major]</dt><dd>Ignores all future minor/major
updates for this dependency and closes this PR</dd>
<dt>@depfu resume</dt><dd>Future versions of this dependency will
create PRs again (leaves this PR as is)</dd>
</dl></blockquote>
</details>
Co-authored-by: depfu[bot] <23717796+depfu[bot]@users.noreply.github.com>
Here is everything you need to know about this update. Please take a
good look at what changed and the test results before merging this pull
request.
### What changed?
#### ✳️ enhanced-resolve (5.17.1 → 5.18.0) ·
[Repo](https://github.com/webpack/enhanced-resolve)
<details>
<summary>Release Notes</summary>
<h4><a
href="https://github.com/webpack/enhanced-resolve/releases/tag/v5.18.0">5.18.0</a></h4>
<blockquote><h3 dir="auto">Features</h3>
<ul dir="auto">
<li>Added wildcards support for aliases</li>
</ul></blockquote>
<p><em>Does any of this look wrong? <a
href="https://depfu.com/packages/npm/enhanced-resolve/feedback">Please
let us know.</a></em></p>
</details>
<details>
<summary>Commits</summary>
<p><a
href="247edebc90...27e457a905">See
the full diff on Github</a>. The new version differs by 9 commits:</p>
<ul>
<li><a
href="27e457a905"><code>chore(release):
5.18.0</code></a></li>
<li><a
href="88ceebe3cc"><code>feat:
add wildcards support for aliases</code></a></li>
<li><a
href="35b67ce834"><code>feat:
add wildcards</code></a></li>
<li><a
href="4fbcfa1c83"><code>chore(deps):
bump cross-spawn from 7.0.3 to 7.0.6</code></a></li>
<li><a
href="572a54f0c6"><code>chore(deps):
bump cross-spawn from 7.0.3 to 7.0.6</code></a></li>
<li><a
href="af4e2fb155"><code>ci:
add Node.js v23</code></a></li>
<li><a
href="bf443c04ac"><code>ci:
add Node.js v23</code></a></li>
<li><a
href="72999caf00"><code>chore(deps):
bump micromatch from 4.0.5 to 4.0.8</code></a></li>
<li><a
href="fbee162cc2"><code>chore(deps):
bump micromatch from 4.0.5 to 4.0.8</code></a></li>
</ul>
</details>
---
[Depfu](https://depfu.com) will automatically keep this PR
conflict-free, as long as you don't add any commits to this branch
yourself. You can also trigger a rebase manually by commenting with
`@depfu rebase`.
<details><summary>All Depfu comment commands</summary>
<blockquote><dl>
<dt>@depfu rebase</dt><dd>Rebases against your default branch and
redoes this update</dd>
<dt>@depfu recreate</dt><dd>Recreates this PR, overwriting any edits
that you've made to it</dd>
<dt>@depfu merge</dt><dd>Merges this PR once your tests are passing and
conflicts are resolved</dd>
<dt>@depfu cancel merge</dt><dd>Cancels automatic merging of this
PR</dd>
<dt>@depfu close</dt><dd>Closes this PR and deletes the branch</dd>
<dt>@depfu reopen</dt><dd>Restores the branch and reopens this PR (if
it's closed)</dd>
<dt>@depfu pause</dt><dd>Ignores all future updates for this dependency
and closes this PR</dd>
<dt>@depfu pause [minor|major]</dt><dd>Ignores all future minor/major
updates for this dependency and closes this PR</dd>
<dt>@depfu resume</dt><dd>Future versions of this dependency will
create PRs again (leaves this PR as is)</dd>
</dl></blockquote>
</details>
Co-authored-by: depfu[bot] <23717796+depfu[bot]@users.noreply.github.com>
This PR improves the codemod tool to simplify 2 things:
1. Whenever you have a `theme(…)` call, we try to change it to a
`var(…)`, but if that doesn't work for some reason, we will make sure to
at least convert it to the more modern `--theme(…)`.
2. When converting `theme(spacing.2)`, we used to convert it to
`calc(var(--spacing)*2)`, but now we will convert it to `--spacing(2)`
instead.
This PR prevents the migration of utilities detected in function names,
e.g.: the use of `shadow` inside `filter: 'drop-shadow(…)'`.
## Test plan
Have content like this in a project you're migrating using the upgrade
tool:
```js
{
filter: 'drop-shadow(0 0 0.5rem #000)'
}
```
This was verified by adding unit tests to the specific codemods and
adding an integration test.
`overflow-clip` was the name for `text-clip` in v4. However, that was
changed in v3 already so in v3 `overflow-clip` is already doing the same
as in v4. Hence a codemod is not necessary.
Co-authored-by: Adam Wathan <adam.wathan@gmail.com>
This PR improves the performance of the `@tailwindcss/postcss` and
`@tailwindcss/vite` implementations.
The issue is that in some scenarios, if you have multiple `.css` files,
then all of the CSS files are ran through the Tailwind CSS compiler. The
issue with this is that in a lot of cases, the CSS files aren't even
related to Tailwind CSS at all.
E.g.: in a Next.js project, if you use the `next/font/local` tool, then
every font you used will be in a separate CSS file. This means that we
run Tailwind CSS in all these files as well.
That said, running Tailwind CSS on these files isn't the end of the
world because we still need to handle `@import` in case `@tailwind
utilities` is being used. However, we also run the auto source detection
logic for every CSS file in the system. This part is bad.
To solve this, this PR introduces an internal `features` to collect what
CSS features are used throughout the system (`@import`, `@plugin`,
`@apply`, `@tailwind utilities`, etc…)
The `@tailwindcss/postcss` and `@tailwindcss/vite` plugin can use that
information to decide if they can take some shortcuts or not.
---
Overall, this means that we don't run the slow parts of Tailwind CSS if
we don't need to.
---------
Co-authored-by: Adam Wathan <adam.wathan@gmail.com>
Resolves#15193
This PR fixes an issue where `group` and `peer` would not have their
prefixes migrated as part of the upgrade script. We do this by
registering `group` and `peer` as utilities during the codemods. This
way, `parseCandidate` will find these classes to be valid Tailwind
candidates and the prefix can be migrated just like any other utility.
## Test Plan
Tried it with the v3 upgrade playground in the repo and it worked fine:
<img width="1257" alt="Screenshot 2024-11-27 at 12 17 25"
src="https://github.com/user-attachments/assets/1ee101e1-1d6a-4ce0-b0d4-8d51e5f6b0d2">
I've also added tests to our prefix upgrade integration test and the
prefix migration unit tests.
This PR ensures that when we inject `layer(…)` into an `@import` that it
always gets inserted as the first param. The `layer(…)` has to come
first by spec.
Input:
```css
@import "./foo" supports(--foo);
```
Before:
```css
@import "./foo" supports(--foo) layer(utilities);
```
After:
```css
@import "./foo" layer(utilities) supports(--foo);
```
Closes#15071
This PR reverts the changes in #15036 which add consistent base styles
for buttons and form controls to Preflight.
While this felt like a good idea (for the reasons explained in that PR),
practically this is just too disruptive of a change for people upgrading
from v3 to v4.
While updating some of our projects to v4 we found ourselves adding
classes to undo styles more often than we expected, and it also felt
inconsistent to have to use a different set of classes to style a link
or a button when we wanted them to look the same.
We also decided it feels a little strange that you could change the
border color of an element without ever specifying that it should have a
border, for example this just feels a little wrong:
```html
<button class="border-blue-500">
```
We also needed to set a default `color-scheme` value for any of this
stuff to work which breaks the ability to use the `color-scheme` meta
tag.
Since this change was a fairly major breaking change and we aren't
feeling much benefit from it, it doesn't feel worth making this change
for v4.
---------
Co-authored-by: Philipp Spiess <hello@philippspiess.com>
This PR improves compatibility for named `opacity` theme values. One of
the changes in v4 is that we use the CSS `color-mix()` function to apply
opacity to colors. This, however, is limited to percentage values only:
```css
color: color-mix(in oklch, var(--color-red-500) 50%, transparent);
/* ^^^ */
/* This needs to be a percentage value */
```
In v3, however, it was common to specify custom opacity values as
decimal numbers. That's also what we did in our default config:
6069a81187/stubs/config.full.js (L703-L725)
This PR improves interop with these values by:
1. Converting decimal numbers in the range of `[0, 1]` to their
percentage value equivalent when using the interop layer.
2. Adjusts the codemod that migrates `opacity` theme keys to Tailwind v4
theme variables to include the same conversion.
3. Furthermore, due to the added support of named opacity modifers, we
can also drop theme keys that would now be the default. For example the
following config would not be necessary in v4 as the opacity modifier
would accept the value `50` by default:
```js
module.exports = {
theme: {
opacity: {
50: 0.5
}
}
}
```
## Test Plan
Added a new integration test for the codemod and a unit test for the
interop layer. I also re-ran the codemod on the Commit template and it's
now working as expected (left is v3, right is v4):
<img width="2560" alt="Screenshot 2024-11-21 at 17 25 32"
src="https://github.com/user-attachments/assets/f0c87243-ca80-4c39-ae5e-c1ab48fbe614">
While testing the latest alpha release across Tailwind v3 projects, we
noticed one regression in relation to the default color of `<button>`
elements. In v3, the reset would change the default to `inherit` but in
v4 we would _not include it in the reset snippet inserted by the upgrade
too_.
This PR changes the upgrade snippet to include it:
```diff
/*
In Tailwind CSS v4, basic styles are applied to form elements by default. To
maintain compatibility with v3, the following resets have been added:
*/
@layer base {
input,
textarea,
select,
button {
border: 0px solid;
border-radius: 0;
padding: 0;
+ color: inherit;
background-color: transparent;
}
}
```
This PR also ensures that there's a newline between the two code
snippets.
## Test Plan
### Before
### After
<img width="1354" alt="Screenshot 2024-11-21 at 15 42 58"
src="https://github.com/user-attachments/assets/9a4503fe-683f-4d08-abf2-7dd111ed5428">
This PR makes the candidate parser more strict by not allowing empty
arbitrary values.
Examples that are not allowed anymore:
- `bg-[]` — arbitrary value
- `bg-()` — arbitrary value, var shorthand
- `bg-[length:]` — arbitrary value, with typehint
- `bg-(length:)` — arbitrary value, with typehint, var shorthand
- `bg-red-500/[]` — arbitrary modifier
- `bg-red-500/()` — arbitrary modifier, var shorthand
- `data-[]:flex` — arbitrary value for variant
- `data-():flex` — arbitrary value for variant, var shorthand
- `group-visible/[]:flex` — arbitrary modifier for variant
- `group-visible/():flex` — arbitrary modifier for variant, var
shorthand
If you are trying to trick the parser by injecting some spaces like
this:
- `bg-[_]`
Then that is also not allowed.
This PR introduces consistent base styles for buttons and form controls
in Tailwind CSS v4.
## Motivation
In v3, form elements lack default styles, which can be
confusing—especially when certain elements, like a text input without a
placeholder or value, are rendered completely invisible on the page.
The goal of this change is to provide reasonable default styles for
buttons, inputs, selects, and textareas that are (mostly) consistent
across all browsers while remaining easy to customize with your own
styles.
This improvement should make Tailwind more accessible for developers new
to the framework and more convenient in scenarios where you need to
quickly create demos (e.g., using Tailwind Play).
## Light and dark mode support
These styles support both light and dark mode, achieved using the
`light-dark()` CSS function. While browser support for this function is
still somewhat limited, Lightning CSS transpiles it to a CSS
variable-based approach that works in older browsers.
For this approach to function correctly, a default `color-scheme` must
be set in your CSS (as explained in [the Lightning CSS
documentation](https://lightningcss.dev/transpilation.html#light-dark()-color-function)).
This PR addresses this requirement by setting the `color-scheme` to
`light` on the `html` element in Preflight.
<img width="1712" alt="image"
src="https://github.com/user-attachments/assets/dba56368-1427-47b3-9419-7c2f6313a944">
<img width="1709" alt="image"
src="https://github.com/user-attachments/assets/3d84fcd2-9606-4626-8e03-164a1dce9018">
## Breaking changes
While we don’t expect these changes to significantly impact v3 users
upgrading to v4, there may be minor differences for those relying on the
simpler v3 styles.
For example, Preflight now applies a `border-radius` to buttons and form
controls. If you weren’t explicitly setting the border radius to `0` in
your project, you’ll need to do so to restore the previous look.
Thankfully, reverting to the v3 styles is straightforward—just add the
following reset to your CSS:
```css
@layer base {
input,
textarea,
select,
button {
border: 0px solid;
border-radius: 0;
padding: 0;
background-color: transparent;
}
}
```
It’s worth noting that this reset doesn't touch the
`::file-selector-button` styles that were added in this PR. This is
because it's not possible to reliably "undo" these styles and restore
the original user-agent styles (which is what was used in v3), as these
are different in each browser. However, these new styles actually match
the defaults in most browsers pretty closely, so hopefully this just
won't be an issue.
## Codemod
This PR includes a codemod that automatically inserts the above
mentioned v3 reset to help avoid breaking changes during the upgrade.
The codemod will insert the following CSS:
```css
/*
In Tailwind CSS v4, basic styles are applied to form elements by default. To
maintain compatibility with v3, the following resets have been added:
*/
@layer base {
input,
textarea,
select,
button {
border: 0px solid;
border-radius: 0;
padding: 0;
background-color: transparent;
}
}
```
## Testing
These changes have been tested across a wide range of browsers,
including Chrome, Safari, Firefox, Edge, and Opera on macOS and Windows,
as well as Safari, Chrome, Firefox, and several lesser-known browsers on
iOS and Android.
However, some quirks still exist in certain mobile browsers, such as iOS
Safari, which adds too much bottom padding below date and time inputs:
<img width="1548" alt="Screenshot 2024-11-20 at 3 57 20 PM"
src="https://github.com/user-attachments/assets/507c7724-ac41-4634-a2b3-61ac4917ebce">
The only reliable way to address these issues is by applying
`appearance: none` to these form controls. However, this felt too
opinionated for Preflight, so we’ve opted to leave such adjustments to
user-land implementations.
---------
Co-authored-by: Jonathan Reinink <jonathan@reinink.ca>
Co-authored-by: Jordan Pittman <jordan@cryptica.me>
While testing the codemods on some projects, I noticed some issues with
the migration to the new `in-*` variant.
One such example is that we checked for `&` at the end, instead of ` &`
(the whitespace is significant).
This meant that `[figure>&]:my-0` was converted to `in-[figure>]:my-0`
which is wrong. In this case, we want to keep it as `[figure>&]:my-0`.
Additionally this PR brings back the migration from `group-[]:flex` to
`in-[.group]:flex`. If you are using a prefix, then `group-[]:tw-flex`
is migrated to `tw:in-[.tw\:group]:flex`.
Last but not least, this does some internal refactors to group
migrations logically together.
This PR fixes an issue where the Tailwind root file detection was wrong.
Whenever a CSS file contains any of the `@tailwind` directives or an
`@import` to any of the Tailwind files, the file is considered a
Tailwind root file.
If multiple CSS files are part of the same tree, then we make the
nearest common parent the root file.
This root file will be the file where we add `@config` and/or inject
other changes during the migration process.
However, if your folder structure looked like this:
```css
/* index.css */
@import "./base.css";
@import "./typography.css";
@import "tailwindcss/components"; /* This makes index.css a root file */
@import "./utilities.css";
/* base.css */
@tailwind base; /* This makes base.css a root file */
/* utilities.css */
@tailwind utilities; /* This makes utilities.css a root file */
```
Then we computed that `index.css` nad `base.css` were considered root
files even though they belong to the same tree (because `base.css` is
imported by `index.css`).
This PR fixes that behaviour by essentially being less smart, and just
checking again if any sheets are part of the same tree.
# Test plan:
Added an integration test that covers this scenario and fails before the
fix.
Also ran it on our tailwindcss.com codebase.
| Before | After |
| --- | --- |
| <img width="1072" alt="image"
src="https://github.com/user-attachments/assets/8ee99a59-335e-4221-b368-a8cd81e85191">
| <img width="1072" alt="image"
src="https://github.com/user-attachments/assets/fe5acae4-d3fc-43a4-bd31-eee768a3a6a5">
|
(Yes, I know the migration still fails, but that's a different issue.)
If you have a PostCSS config file, that is not simple (has functions,
requires, ...). In that case we don't migrate the PostCSS file. Because
we don't migrate, the `didMigrate` is still false and we continue with
the next migration.
The issue here is that there are 2 states encoded in the same variable
and they should be two separate variables because there is a difference
between:
1. Not finding a file at all
2. Finding a file, but not migrating it
Before this change, the output looks like this if you have a complex
PostCSS file:
```
│ Migrating PostCSS configuration…
│ The PostCSS config contains dynamic JavaScript and can not be automatically migrated.
│ No PostCSS config found, skipping migration.
```
After this change, the output looks like this:
```
│ Migrating PostCSS configuration…
│ ↳ The PostCSS config contains dynamic JavaScript and can not be automatically migrated.
```
Also updated the output to include `↳ ` to be consistent with the other
logs.
This PR uses the `enhanced-resolve` instead of
`createRequire(…).resolve` which improves the usability when running the
upgrade tool locally using Bun.
While testing, we also noticed that it is not possible to use a
`cjs`-only plugin inside of an `esm` project. It was also not possible
to use an `esm`-only plugin inside of a `cjs` project.
# Test plan
We added integration tests in both the CLI (the CLI is an mjs project)
and in the PostCSS (where we can configure a `cjs` and `esm` PostCSS
config) integration tests where we created an `esm` and `cjs` based
project with 4 plugins (`cjs`-only, `esm`-only, and TypeScript based
plugins: `cts`-only and `mts`-only).
This implements backwards compatibility for colors that use the old
`<alpha-value>` feature from v3. We can do this by replacing
`<alpha-value>` with `1` because we use `color-mix` to actually apply
opacity modifiers in v4.
In some local testing we ran the `@tailwindcss/upgrade` command twice in
a row. It would be great to get some feedback that this is not working,
so this PR now checks if it can resolve the installed version of
`tailwindcss` and if it can, it requires it to be < 4 (you can bypass
this check with `--force`).
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
