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 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!;
}
```
