This PR ensures that the `@tailwindcss/upgrade` tool works on existing
Tailwind CSS v4 projects. This PR also ensures that the upgrade tool is
idempotent, meaning that it can be run multiple times and it should
result in the same output.
One awesome feature this unlocks is that you can run the upgrade tool on
your codebase at any time and upgrade classes if you still have some
legacy syntaxes, such as `bg-[var(--my-color)]`, in your muscle memory.
One small note: If something changed in the first run, re-running will
not work immediately because your git repository will not be clean and
the upgrade tool requires your git repo to be clean. But once you
verified and committed your changes, the upgrade tool will be
idempotent.
Idempotency is guaranteed by ensuring that some migrations are skipped
by checking what version of Tailwind CSS you are on _before_ the version
is upgraded.
For the Tailwind CSS version: We will resolve `tailwindcss` itself to
know the _actual_ version that is installed (the one resolved from
`node_modules`). Not the one available in your package.json. Your
`package.json` could be out of sync if you reverted changes but didn't
run `npm install` yet.
Back to Idempotency:
For example, we have migrations where we change the variant order of
stacked variants. If we would run these migrations every time you run
the upgrade tool then we would be flip-flopping the order every run.
See: https://tailwindcss.com/docs/upgrade-guide#variant-stacking-order
Another example is where we rename some utilities. For example, we
rename:
| Before | After |
| ----------- | ----------- |
| `shadow` | `shadow-sm` |
| `shadow-sm` | `shadow-xs` |
Notice how we have `shadow-sm` in both the `before` and `after` column.
If we would run the upgrade tool again, then we would eventually migrate
your original `shadow` to `shadow-sm` (first run) and then to
`shadow-xs` (second run). Which would result in the wrong shadow.
See: https://tailwindcss.com/docs/upgrade-guide#renamed-utilities
---
The order of upgrade steps changed a bit as well to make the internals
are easier to work with and reason about.
1. Find CSS files
2. Link JS config files (if you are in a Tailwind CSS v3 project)
3. Migrate the JS config files (if you are in a Tailwind CSS v3 project)
4. Upgrade Tailwind CSS to v4 (or the latest version at that point)
5. Migrate the stylesheets (we used to migrate the source files first)
6. Migrate the source files
This is done so that step 5 and 6 will always operate on a Tailwind CSS
v4 project and we don't need to check the version number again. This is
also necessary because your CSS file will now very likely contain
`@import "tailwindcss";` which doesn't exist in Tailwind CSS v3.
This also means that we can rely on the same internals that Tailwind CSS
actually uses for locating the source files. We will use
`@tailwindcss/oxide`'s scanner to find the source files (and it also
keeps your custom `@source` directives into account).
This PR also introduces a few actual migrations related to recent
features and changes we shipped.
1. We migrate deprecated classes to their new names:
| Before | After |
| --------------------- | --------------------- |
| `bg-left-top` | `bg-top-left` |
| `bg-left-bottom` | `bg-bottom-left` |
| `bg-right-top` | `bg-top-right` |
| `bg-right-bottom` | `bg-bottom-right` |
| `object-left-top` | `object-top-left` |
| `object-left-bottom` | `object-bottom-left` |
| `object-right-top` | `object-top-right` |
| `object-right-bottom` | `object-bottom-right` |
Introduced in:
- https://github.com/tailwindlabs/tailwindcss/pull/17378
- https://github.com/tailwindlabs/tailwindcss/pull/17437
2. We migrate simple arbitrary variants to their dedicated variant:
| Before | After |
| ----------------------- | ------------------- |
| `[&:user-valid]:flex` | `user-valid:flex` |
| `[&:user-invalid]:flex` | `user-invalid:flex` |
Introduced in:
- https://github.com/tailwindlabs/tailwindcss/pull/12370
3. We migrate `@media` variants to their dedicated variant:
| Before | After |
| ----------------------------------------------------- |
------------------------- |
| `[@media_print]:flex` | `print:flex` |
| `[@media(prefers-reduced-motion:no-preference)]:flex` |
`motion-safe:flex` |
| `[@media(prefers-reduced-motion:reduce)]:flex` | `motion-reduce:flex`
|
| `[@media(prefers-contrast:more)]:flex` | `contrast-more:flex` |
| `[@media(prefers-contrast:less)]:flex` | `contrast-less:flex` |
| `[@media(orientation:portrait)]:flex` | `portrait:flex` |
| `[@media(orientation:landscape)]:flex` | `landscape:flex` |
| `[@media(forced-colors:active)]:flex` | `forced-colors:flex` |
| `[@media(inverted-colors:inverted)]:flex` | `inverted-colors:flex` |
| `[@media(pointer:none)]:flex` | `pointer-none:flex` |
| `[@media(pointer:coarse)]:flex` | `pointer-coarse:flex` |
| `[@media(pointer:fine)]:flex` | `pointer-fine:flex` |
| `[@media(any-pointer:none)]:flex` | `any-pointer-none:flex` |
| `[@media(any-pointer:coarse)]:flex` | `any-pointer-coarse:flex` |
| `[@media(any-pointer:fine)]:flex` | `any-pointer-fine:flex` |
| `[@media(scripting:none)]:flex` | `noscript:flex` |
The new variants related to `inverted-colors`, `pointer`, `any-pointer`
and `scripting` were introduced in:
- https://github.com/tailwindlabs/tailwindcss/pull/11693
- https://github.com/tailwindlabs/tailwindcss/pull/16946
- https://github.com/tailwindlabs/tailwindcss/pull/11929
- https://github.com/tailwindlabs/tailwindcss/pull/17431
This also applies to the `not` case, e.g.:
| Before | After |
| --------------------------------------------------------- |
----------------------------- |
| `[@media_not_print]:flex` | `not-print:flex` |
| `[@media_not(prefers-reduced-motion:no-preference)]:flex` |
`not-motion-safe:flex` |
| `[@media_not(prefers-reduced-motion:reduce)]:flex` |
`not-motion-reduce:flex` |
| `[@media_not(prefers-contrast:more)]:flex` | `not-contrast-more:flex`
|
| `[@media_not(prefers-contrast:less)]:flex` | `not-contrast-less:flex`
|
| `[@media_not(orientation:portrait)]:flex` | `not-portrait:flex` |
| `[@media_not(orientation:landscape)]:flex` | `not-landscape:flex` |
| `[@media_not(forced-colors:active)]:flex` | `not-forced-colors:flex` |
| `[@media_not(inverted-colors:inverted)]:flex` |
`not-inverted-colors:flex` |
| `[@media_not(pointer:none)]:flex` | `not-pointer-none:flex` |
| `[@media_not(pointer:coarse)]:flex` | `not-pointer-coarse:flex` |
| `[@media_not(pointer:fine)]:flex` | `not-pointer-fine:flex` |
| `[@media_not(any-pointer:none)]:flex` | `not-any-pointer-none:flex` |
| `[@media_not(any-pointer:coarse)]:flex` |
`not-any-pointer-coarse:flex` |
| `[@media_not(any-pointer:fine)]:flex` | `not-any-pointer-fine:flex` |
| `[@media_not(scripting:none)]:flex` | `not-noscript:flex` |
For each candidate, we run a set of upgrade migrations. If at the end of
the migrations the original candidate is still the same as the new
candidate, then we will parse & print the candidate one more time to
pretty print into consistent classes. Luckily parsing is cached so there
is no real downside overhead.
Consistency (especially with arbitrary variants and values) will reduce
your CSS file because there will be fewer "versions" of your class.
Concretely, the pretty printing will apply changes such as:
| Before | After |
| ---------------------- | ----------------- |
| `bg-[var(--my-color)]` | `bg-(--my-color)` |
| `bg-[rgb(0,_0,_0)]` | `bg-[rgb(0,0,0)]` |
Another big important reason for this change is that these classes on
their own
would have been migrated _if_ another migration was relevant for this
candidate.
This means that there are were some inconsistencies. E.g.:
| Before | After | Reason |
| ----------------------- | ---------------------- |
------------------------------------ |
| `!bg-[var(--my-color)]` | `bg-(--my-color)!` | Because the `!` is in
the wrong spot |
| `bg-[var(--my-color)]` | `bg-[var(--my-color)]` | Because no
migrations rand |
As you can see, the way the `--my-color` variable is used, is different.
This
changes will make sure it will now always be consistent:
| Before | After |
| ----------------------- | ---------------------- |
| `!bg-[var(--my-color)]` | `bg-(--my-color)!` |
| `bg-[var(--my-color)]` | `bg-(--my-color)` |
Yay!
Of course, if you don't want these more cosmetic changes, you can always
ignore the upgrade and revert these changes and only commit the changes
you want.
# Test plan
- All existing tests still pass.
- But I had to delete 1 test (we tested that Tailwind CSS v3 was
required).
- And had to mock the `version.isMajor` call to ensure we run the
individual migration tests correctly.
- Added new tests to test:
1. Migrating Tailwind CSS v4 projects works
1. Idempotency of the upgrade tool
[ci-all]
This PR is an internal refactor of the codemods package structure that
will make a few follow-up PRs easier.
Essentially what happens is:
1. Moved `./src/template/` into `src/codemods/template/`
2. Moved `./src/codemods` into `./src/codemods/css` (because the CSS
related codemods already)
3. Moved the migration files for the JS config, PostCSS config and
Prettier config into `./src/codemods/config/`.
4. Made filenames with actual migrations consistent by prefixing them
with `migrate-`.
5. Made sure that all the migration functions also use `migrate…`
When looking at this PR, go commit by commit, it will be easier. In a
lot of cases, it's just moving files around but those commits also come
with changes to the code just to update the imports.
[ci-all]
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>
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 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>
This PR reverts a change we made for v4 that added borders to inputs by
default. It feels like we have to go further than this for this to
actually be useful to anyone, and since there were no borders in v3 it's
also a breaking change.
If we wanted to make form elements look more "normal" out of the box I
think we need to do something more like this:
https://play.tailwindcss.com/icCwFLVp4z?file=css
But it's a huge rabbit hole and there are so many stupid details to get
right that it feels like an insurmountable task, and if we can't go all
the way with it it's better to just maximize compatibility with v3.
---------
Co-authored-by: Adam Wathan <4323180+adamwathan@users.noreply.github.com>
During the migration process, a lot of changes to the CSS file happen.
Some parts are converted, some parts are deleted and some new CSS is
added.
To make sure we are generating a sensible and good looking CSS file, we
will sort the final CSS and pretty print it.
The order we came up with looks like this:
```css
/* Imports */
@import "tailwindcss";
@import "../other.css";
/* Configuration */
@config "../path/to/tailwindcss.config.js";
@plugin "my-plugin-1";
@plugin "my-plugin-2";
@source "./foo/**/*.ts";
@source "./bar/**/*.ts";
@variant foo {}
@variant bar {}
@theme {}
/* Border compatibility CSS */
@layer base {}
/* Utilities */
@utility foo {}
@utility bar {}
/* Rest of your own CSS if any */
```
---------
Co-authored-by: Philipp Spiess <hello@philippspiess.com>
When migrating a project from Tailwind CSS v3 to Tailwind CSS v4, then
we started the migration process in the following order:
1. Migrate the JS/TS config file
2. Migrate the source files (found via the `content` option)
3. Migrate the CSS files
However, if you have a setup where you have multiple CSS root files
(e.g.: `frontend` and `admin` are separated), then that typically means
that you have an `@config` directive in your CSS files. These point to
the Tailwind CSS config file.
This PR changes the migration order to do the following:
1. Build a tree of all the CSS files
2. For each `@config` directive, migrate the JS/TS config file
3. For each JS/TS config file, migrate the source files
If a CSS file does not contain any `@config` directives, then we start
by filling in the `@config` directive with the default Tailwind CSS
config file (if found, or the one passed in). If no default config file
or passed in config file can be found, then we will error out (just like
we do now)
---------
Co-authored-by: Adam Wathan <adam.wathan@gmail.com>
This PR adds a codemod that ensures that the border styles from Tailwind CSS v3 work as expected once your project is migrated to Tailwind CSS v4.
In Tailwind CSS v3, the default border color is `colors.gray.200` and in Tailwind CSS v4 the default border color is `currentColor`.
Similarly in Tailwind CSS v3, DOM elements such as `input`, `select`, and `textarea` have a border width of `0px`, in Tailwind CSS v4, we don't change the border width of these elements and keep them as `1px`.
If your project happens to already use the same value for the default border color (`currentColor`) as we use in Tailwind CSS v4, then nothing happens. But this is very unlikely, so we will make sure that we honor your `borderColor.DEFAULT` value.
If you didn't change the default values in your `tailwind.config.js`, then we will inject compatibility CSS using the default Tailwind CSS v3 values to ensure the default color and width are applied correctly.
This PR implements the first version of JS config file migration to CSS.
It is based on the most simple config setups we are using in the
Tailwind UI templates Commit, Primer, Radiant, and Studio.
The example we use in the integration test is a config that looks like
this:
```js
import { type Config } from 'tailwindcss'
import defaultTheme from 'tailwindcss/defaultTheme'
module.exports = {
darkMode: 'selector',
content: ['./src/**/*.{html,js}'],
theme: {
boxShadow: {
sm: '0 2px 6px rgb(15 23 42 / 0.08)',
},
colors: {
red: {
500: '#ef4444',
},
},
fontSize: {
xs: ['0.75rem', { lineHeight: '1rem' }],
sm: ['0.875rem', { lineHeight: '1.5rem' }],
base: ['1rem', { lineHeight: '2rem' }],
},
extend: {
colors: {
red: {
600: '#dc2626',
},
},
fontFamily: {
sans: 'Inter, system-ui, sans-serif',
display: ['Cabinet Grotesk', ...defaultTheme.fontFamily.sans],
},
borderRadius: {
'4xl': '2rem',
},
},
},
plugins: [],
} satisfies Config
```
As you can see, this file only has a `darkMode` selector, custom
`content` globs, a `theme` (with some theme keys being overwriting the
default theme and some others extending the defaults). Note that it does
not support `plugins` and/or `presets` yet.
In the case above, we will find the CSS file containing the existing
`@tailwind` directives and are migrating it to the following:
```css
@import 'tailwindcss';
@source './**/*.{html,js}';
@variant dark (&:where(.dark, .dark *));
@theme {
--box-shadow-*: initial;
--box-shadow-sm: 0 2px 6px rgb(15 23 42 / 0.08);
--color-*: initial;
--color-red-500: #ef4444;
--font-size-*: initial;
--font-size-xs: 0.75rem;
--font-size-xs--line-height: 1rem;
--font-size-sm: 0.875rem;
--font-size-sm--line-height: 1.5rem;
--font-size-base: 1rem;
--font-size-base--line-height: 2rem;
--color-red-600: #dc2626;
--font-family-sans: Inter, system-ui, sans-serif;
--font-family-display: Cabinet Grotesk, ui-sans-serif, system-ui, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
--border-radius-4xl: 2rem;
}
```
This replicates all features of the JS config so we can even delete the
existing JS config in this case.
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
This PR injects a `@config "…"` in the CSS file if a JS based config has
been found.
We will try to inject the `@config` in a sensible place:
1. Above the very first `@theme`
2. If that doesn't work, below the last `@import`
3. If that doesn't work, at the top of the file (as a last resort)
When a stylesheet is imported with `@import “…” layer(utilities)` that
means that all classes in that stylesheet and any of its imported
stylesheets become candidates for `@utility` conversion.
Doing this correctly requires us to place `@utility` rules into separate
stylesheets (usually) and replicate the import tree without layers as
`@utility` MUST be root-level. If a file consists of only utilities we
won't create a separate file for it and instead place the `@utility`
rules in the same stylesheet.
Been doing a LOT of pairing with @RobinMalfait on this one but I think
this is finally ready to be looked at
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
In order to properly migrate your Tailwind CSS v3 project to v4, we need
access to the JavaScript configuration object. This was previously only
required for template migrations, but in this PR we're making it so that
this is also a prerequisite of the CSS migrations. This is because some
migrations, like `@apply`, also need to convert candidates that to the
v4 syntax and we need the full config in order to properly validate
them.
In addition to requiring a JS config, we also now attempt to
automatically find the right configuration file inside the current
working directory. This is now matching the behavior of the Tailwind CSS
v3 CLI where it will find the config automatically if it's in the
current directory and called `tailwind.conf.js`.
---------
Co-authored-by: Robin Malfait <malfait.robin@gmail.com>
This PR fixes an issue where CSS that existed before a layer:
```css
.foo {
color: red;
}
@layer components {
.bar {
color: blue;
}
}
```
Was turned into an `@layer` without a name:
```css
@layer {
.foo {
color: red;
}
}
@utility bar {
color: blue;
}
```
But in this case, it should stay as-is:
```css
.foo {
color: red;
}
@utility bar {
color: blue;
}
```
This PR adds a new migration that can migrate Tailwind CSS v3 style
prefixes into Tailwind CSS v4.
The migration is split into three separate pieces of work:
1. Firstly, we need to read the full JavaScript config to get the _old_
prefix option. This is necessary because in v4, we will not allow things
like custom-separators for the prefix. From this option we will then try
and compute a new prefix (in 90% of the cases this is going to just
remove the trailing `-` but it can also work in more complex cases).
2. Then we migrate all Candidates. The important thing here is that we
need to operate on the raw candidate string because by relying on
`parseCandidate` (which we do for all other migrations) would not work,
as the candidates are not valid in v4 syntax. More on that in a bit.
3. Lastly we also make sure to update the CSS config to include the new
prefix. This is done by prepending the prefix option like so:
```css
@import "tailwindcss" prefix(tw);
```
### Migrating candidates
The main difference between v3 prefixes and v4 prefixes is that in v3,
the prefix was _part of the utility_ where as in v4 it is _always in
front of the CSS class.
So, for example, this candidate in v3:
```
hover:-tw-mr-4
```
Would be converted to the following in v4:
```
tw:hover:-mr-4
```
Since the first example _won't parse as a valid Candidate in v4, as the
`tw-mr` utility does not exist, we have to operate on the raw candidate
string first. To do this I created a fork of the `parseCandidate`
function _without any validation of utilities or variants_. This is used
to identify part of the candidate that is the `base` and then ensuring
the `base` starts with the old prefix. We then remove this to create an
"unprefixed" candidate that we validate against a version of the
DesignSystem _with no prefixes configured_. If the variant is valid this
way, we can then print it again with the `DesignSystem` that has the new
prefix to get the migrated version.
Since we set up the `DesignSystem` to include the new prefix, we can
also be certain that migrations that happen afterwards would still
disqualify candidates that aren't valid according to the new prefix
policy. This does mean we need to have the prefix fixup be the first
step in our pipeline.
One interesting bit is that in v3, arbitrary properties did not require
prefixes where as in v4 they do. So the following candidate:
```
[color:red]
```
Will be converted to:
```
tw:[color:red]
```
This PR inserts the `@import` in a more sensible location when running
codemods.
The idea is that we replace `@tailwind base; @tailwind components;
@tailwind utilities;` with the much simple `@import "tailwindcss";`. We
did this by adding the `@import` to the top of the file.
While this is correct, this means that the diff might not be as clear.
For example, if you have a situation where you have a license comment:
```css
/**! My license comment */
@tailwind base;
@tailwind components;
@tailwind utilities;
```
This resulted in:
```css
@import "tailwindcss";
/**! My license comment */
```
While it is not wrong, it feels weird that this behaves like this. In
this commit we make sure that it is injected in-place (the first
`@tailwind` at-rule we find) and fixup the position if we can't inject
it in-place.
The above example results in this:
```css
/**! My license comment */
@import "tailwindcss";
```
However, there are scenario's where you can't replace the `@tailwind`
directives directly. E.g.:
```css
/**! My license comment */
html {
color: red;
}
@tailwind base;
@tailwind components;
@tailwind utilities;
```
If we replace the `@tailwind` directives in-place, it would look like
this:
```css
/**! My license comment */
html {
color: red;
}
@import "tailwindcss";
```
But this is invalid CSS, because you can't have CSS above an `@import`
at-rule. There are some exceptions like:
- `@charset`
- `@import`
- `@layer foo, bar;` (just the order, without a body)
- comments
In this scenario, we inject the import in the nearest place where it is
allowed to. In this case:
```css
/**! My license comment */
@import "tailwindcss";
@layer base {
html {
color: red;
}
}
```
Additionally, we will wrap the existing CSS in an `@layer` of the first
Tailwind directive we saw. In this case an `@layer base`. This ensures
that utilities still win from the default styles.
Also note that the (license) comment is allowed to exist before the
`@import`, therefore we do not put the `@import` above it. This also
means that the diff doesn't touch the license header at all, which makes
the diffs cleaner and easier to reason about.
---------
Co-authored-by: Philipp Spiess <hello@philippspiess.com>
This PR adds a codemod that ensures that some parts of your stylesheet
are wrapped in an `@layer`.
This is a follow-up PR of #14411, in that PR we migrate `@tailwind`
directives to imports.
As a quick summary, that will turn this:
```css
@tailwind base;
@tailwind components;
@tailwind utilities;
```
Into:
```css
@import 'tailwindcss';
```
But there are a few issues with that _if_ we have additional CSS on the
page. For example let's imagine we had this:
```css
@tailwind base;
body {
background-color: red;
}
@tailwind components;
.btn {}
@tailwind utilities;
```
This will now be turned into:
```css
@import 'tailwindcss';
body {
background-color: red;
}
.btn {}
```
But in v4 we use real layers, in v3 we used to replace the directive
with the result of that layer. This means that now the `body` and `.btn`
styles are in the incorrect spot.
To solve this, we have to wrap them in a layer. The `body` should go in
an `@layer base`, and the `.btn` should be in an `@layer components` to
make sure it's in the same spot as it was before.
That's what this PR does, the original input will now be turned into:
```css
@import 'tailwindcss';
@layer base {
body {
background-color: red;
}
}
@layer components {
.btn {
}
}
```
There are a few internal refactors going on as well, but those are less
important.
This PR adds some initial tooling for codemods. We are currently only
interested in migrating CSS files, so we will be using PostCSS under the
hood to do this. This PR also implements the "migrate `@apply`" codemod
from #14412.
The usage will look like this:
```sh
npx @tailwindcss/upgrade
```
You can pass in CSS files to transform as arguments:
```sh
npx @tailwindcss/upgrade src/**/*.css
```
But, if none are provided, it will search for CSS files in the current
directory and its subdirectories.
```
≈ tailwindcss v4.0.0-alpha.24
│ No files provided. Searching for CSS files in the current
│ directory and its subdirectories…
│ Migration complete. Verify the changes and commit them to
│ your repository.
```
The tooling also requires the Git repository to be in a clean state.
This is a common convention to ensure that everything is undo-able. If
we detect that the git repository is dirty, we will abort the migration.
```
≈ tailwindcss v4.0.0-alpha.24
│ Git directory is not clean. Please stash or commit your
│ changes before migrating.
│ You may use the `--force` flag to override this safety
│ check.
```
---
This PR alsoo adds CSS codemods for migrating existing `@apply`
directives to the new version.
This PR has the ability to migrate the following cases:
---
In v4, the convention is to put the important modifier `!` at the end of
the utility class instead of right before it. This makes it easier to
reason about, especially when you are variants.
Input:
```css
.foo {
@apply !flex flex-col! hover:!items-start items-center;
}
```
Output:
```css
.foo {
@apply flex! flex-col! hover:items-start! items-center;
}
```
---
In v4 we don't support `!important` as a marker at the end of `@apply`
directives. Instead, you can append the `!` to each utility class to
make it `!important`.
Input:
```css
.foo {
@apply flex flex-col !important;
}
```
Output:
```css
.foo {
@apply flex! flex-col!;
}
```
