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7 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Jordan Pittman
|
56b22bb1d3
|
Add support for source maps (#17775)
Closes #13694 Closes #13591 # Source Maps Support for Tailwind CSS This PR adds support for source maps to Tailwind CSS v4 allowing us to track where styles come from whether that be user CSS, imported stylesheets, or generated utilities. This will improve debuggability in browser dev tools and gives us a good foundation for producing better error messages. I'll go over the details on how end users can enable source maps, any limitations in our implementation, changes to the internal `compile(…)` API, and some details and reasoning around the implementation we chose. ## Usage ### CLI Source maps can be enabled in the CLI by using the command line argument `--map` which will generate an inline source map comment at the bottom of your CSS. A separate file may be generated by passing a file name to `--map`: ```bash # Generates an inline source map npx tailwindcss -i input.css -o output.css --map # Generates a separate source map file npx tailwindcss -i input.css -o output.css --map output.css.map ``` ### PostCSS Source maps are supported when using Tailwind as a PostCSS plugin *in development mode only*. They may or may not be enabled by default depending on your build tool. If they are not you may be able to configure them within your PostCSS config: ```jsonc // package.json { // … "postcss": { "map": { "inline": true }, "plugins": { "@tailwindcss/postcss": {}, }, } } ``` ### Vite Source maps are supported when using the Tailwind CSS Vite plugin in *development mode only* by enabling the `css.devSourcemap` setting: ```js import tailwindcss from "@tailwindcss/vite"; import { defineConfig } from "vite"; export default defineConfig({ plugins: [tailwindcss()], css: { devSourcemap: true, }, }) ``` Now when a CSS file is requested by the browser it'll have an inline source map comment that the browser can use. ## Limitations - Production build source maps are currently disabled due to a bug in Lightning CSS. See https://github.com/parcel-bundler/lightningcss/pull/971 for more details. - In Vite, minified CSS build source maps are not supported at all. See https://github.com/vitejs/vite/issues/2830 for more details. - In PostCSS, minified CSS source maps are not supported. This is due to the complexity required around re-associating every AST node with a location in the generated, optimized CSS. This complexity would also have a non-trivial performance impact. ## Testing Here's how to test the source map functionality in different environments: ### Testing the CLI 1. Setup typical project that the CLI can use and with sources to scan. ```css @import "tailwindcss"; @utilty my-custom-utility { color: red; } /* to test `@apply` */ .card { @apply bg-white text-center shadow-md; } ``` 2. Build with source maps: ```bash bun /path/to/tailwindcss/packages/@tailwindcss-cli/src/index.ts --input input.css -o output.css --map ``` 3. Open Chrome DevTools, inspect an element with utility classes, and you should see rules pointing to `input.css` or `node_modules/tailwindcss/index.css` ### Testing with Vite Testing in Vite will require building and installing necessary files under `dist/*.tgz`. 1. Create a Vite project and enable source maps in `vite.config.js`: ```js import tailwindcss from "@tailwindcss/vite"; import { defineConfig } from "vite"; export default defineConfig({ plugins: [tailwindcss()], css: { // This line is required for them to work devSourcemap: true, }, }) ``` 2. Add a component that uses Tailwind classes and custom CSS: ```jsx // ./src/app.jsx export default function App() { return ( <div className="bg-blue-500 my-custom-class"> Hello World </div> ) } ``` ```css /* ./src/styles.css */ @import "tailwindcss"; @utilty my-custom-utility { color: red; } /* to test `@apply` */ .card { @apply bg-white text-center shadow-md; } ``` 3. Run `npm run dev`, open DevTools, and inspect elements to verify source mapping works for both utility classes and custom CSS. ### Testing with PostCSS CLI 1. Create a test file and update your PostCSS config: ```css /* input.css */ @import "tailwindcss"; @layer components { .card { @apply p-6 rounded-lg shadow-lg; } } ``` ```jsonc // package.json { // … "postcss": { "map": { "inline": true }, "plugins": { "/path/to/tailwindcss/packages/packages/@tailwindcss-postcss/src/index.ts": {} } } } ``` 2. Run PostCSS through Bun: ```bash bunx --bun postcss ./src/index.css -o out.css ``` 3. Inspect the output CSS - it should include an inline source map comment at the bottom. ### Testing with PostCSS + Next.js Testing in Next.js will require building and installing necessary files under `dist/*.tgz`. However, I've not been able to get CSS source maps to work in Next.js without this hack: ```js const nextConfig: NextConfig = { // next.js overwrites config.devtool so we prevent it from doing so // please don't actually do this… webpack: (config) => Object.defineProperty(config, "devtool", { get: () => "inline-source-map", set: () => {}, }), }; ``` This is definitely not supported and also doesn't work with turbopack. This can be used to test them temporarily but I suspect that they just don't work there. ### Manual source map analysis You can analyze source maps using Evan Wallace's [Source Map Visualization](https://evanw.github.io/source-map-visualization/) tool which will help to verify the accuracy and quality of source maps. This is what I used extensively while developing this implementation. It'll help verify that custom, user CSS maps back to itself in the input, that generated utilities all map back to `@tailwind utilities;`, that source locations from imported files are also handled correctly, etc… It also highlights the ranges of stuff so it's easy to see if there are off-by-one errors. It's easiest to use inline source maps with this tool because you can take the CSS file and drop it on the page and it'll analyze it while showing the file content. If you're using Vite you'll want to access the CSS file with `?direct` at the end so you don't get a JS module back. ## Implementation The source map implementation follows the ECMA-426 specification and includes several key components to aid in that goal: ### Source Location Tracking Each emittable AST node in the compilation pipeline tracks two types of source locations: - `src`: Original source location - [source file, start offset, end offset] - `dst`: Generated source location - [output file, start offset, end offset] This dual tracking allows us to maintain mappings between the original source and generated output for things like user CSS, generated utilities, uses of `@apply`, and tracking theme variables. It is important to note that source locations for nodes _never overlap_ within a file which helps simplify source map generation. As such each type of node tracks a specific piece of itself rather than its entire "block": | Node | What a `SourceLocation` represents | | ----------- | ---------------------------------------------------------------- | | Style Rule | The selector | | At Rule | Rule name and params, includes the `@` | | Declaration | Property name and value, excludes the semicolon | | Comment | The entire comment, includes the start `/*` and end `*/` markers | ### Windows line endings when parsing CSS Because our AST tracks nodes through offsets we must ensure that any mutations to the file do *not* change the lenth of the string. We were previously replacing `\r\n` with `\n` (see [filter code points](https://drafts.csswg.org/css-syntax/#css-filter-code-points) from the spec) — which changes the length of the string and all offsets may end up incorrect. The CSS parser was updated to handle the CRLF token directly by skipping over the `\r` and letting remaining code handle `\n` as it did previously. Some additional tweaks were required when "peeking" the input but those changes were fairly small. ### Tracking of imports Source maps need paths to the actual imported stylesheets but the resolve step for stylesheets happens inside the call to `loadStylesheet` which make the file path unavailable to us. Because of this the `loadStylesheet` API was augmented such that it has to return a `path` property that we can then use to identify imported sources. I've also made the same change to the `loadModule` API for consistency but nothing currently uses this property. The `path` property likely makes `base` redundant but elminating that (if we even want to) is a future task. ### Optimizing the AST Our optimization pass may intoduce some nodes, for example, fallbacks we create for `@property`. These nodes are linked back to `@tailwind utilities` as ultimately that is what is responsible for creating them. ### Line Offset Tables A key component to our source map generation is the line offset table, which was inspired by some ESBuild internals. It stores a sorted list of offsets for the start of each line allowing us to translate offsets to line/column `Position`s in `O(log N)` time and from `Position`s to offsets in `O(1)` time. Creation of the table takes `O(N)` time. This means that we can store code point offsets for source locations and not have to worry about computing or tracking line/column numbers during parsing and serialization. Only when a source map is generated do these offsets need to be computed. This ensures the performance penalty when not using source maps is minimal. ### Source Map Generation The source map returned by `buildSourceMap()` is designed to follow the [ECMA-426 spec](https://tc39.es/ecma426). Because that spec is not completely finalized we consider the result of `buildSourceMap()` to be internal API that may change as the spec chamges. The produces source map is a "decoded" map such that all sources and mappings are in an object graph. A library like `source-map-js` must be used to convert this to an encoded source map of the right version where mappings are encoded with base 64 VLQs. Any specific integration (Vite, PostCSS, etc…) can then use `toSourceMap()` from `@tailwindcss/node` to convert from the internal source map to an spec-compliant encoded source map that can be understood by other tools. ### Handling minification in Lightning Since we use Lightning CSS for optimization, and it takes in an input map, we generate an encoded source map that we then pass to lightning. The output source map *from lighting itself* is then passed back in during the second optimization pass. The final map is then passed from lightning to the CLI (but not Vite or PostCSS — see the limitations section for details). In some cases we have to "fix up" the output CSS. When this happens we use `magic-string` to do the replacement in a way that is trackable and `@amppproject/remapping` to map that change back onto the original source map. Once the need for these fix ups disappear these dependencies can go away. Notes: - The accuracy of source maps run though lightning is reduced as it only tracks on a per-rule level. This is sufficient enough for browser dev tools so should be fine. - Source maps during optimization do not function properly at this time because of a bug in Lightning CSS regarding license comments. Once this bug is fixed they will start working as expected. ### How source locations flow through the system 1. During initial CSS parsing, source locations are preserved. 2. During parsing these source locations are also mapped to the destinations which supports an optimization for when no utilities are generated. 3. Throughout the compilation process, transformations maintain source location data 4. Generated utilities are explicitly pointed to `@tailwind utilities` unless generated by `@apply`. 5. When optimization is enabled, source maps are remapped through lightningcss 6. Final source maps are written in the requested format (inline or separate file) |
||
Philipp Spiess
|
156afc6d67
|
Improve compatibility with Safari 15 (#17435)
This PR improves the compatibility with Tailwind CSS v4 with unsupported
browsers with the goal to greatly improve compatibility with Safari 15.
To make this work, this PR makes the following changes to all code
- Change `oklab(…)` default theme values to use a percentage in the
first place (so instead of `--color-red-500: oklch(0.637 0.237 25.331);`
we now define it as `--color-red-500: oklch(63.7% 0.237 25.331);` since
this syntax has much broader support on Safari).
- Polyfill `@property` with a `@supports` query targeting older versions
of Safari and Firefox *
- Create fallbacks for the `color-mix(…)` function that use _inlined
color values from your theme_ so that they can be computed a compile
time by `lightningcss`. These fallbacks will convert to srgb to increase
compatibility.
- Create fallbacks for the _relative color_ feature used in the new
shadow utilities and using `color-mix(…)` in case _relative color_ is
applied on `currentcolor` (due to limited browser support)
- Create fallbacks for gradient interpolation methods (e.g. to support
`bg-linear-to-r/oklab`)
- Polyfill `@media` queries range syntax.
## A simplified example
Given this example CSS input:
```css
@import 'tailwindcss';
@source inline('from-cyan-500/50 bg-linear-45');
```
Here's the updated output CSS including the newly added polyfills and
updated `oklab` values:
```css
.bg-linear-45 {
--tw-gradient-position: 45deg;
background-image: linear-gradient(var(--tw-gradient-stops));
}
@supports (background-image: linear-gradient(in lab, red, red)) {
.bg-linear-45 {
--tw-gradient-position: 45deg in oklab;
}
}
.from-cyan-500\\/50 {
--tw-gradient-from: oklab(71.5% -.11682 -.08247 / .5);
--tw-gradient-stops: var(--tw-gradient-via-stops, var(--tw-gradient-position), var(--tw-gradient-from) var(--tw-gradient-from-position), var(--tw-gradient-to) var(--tw-gradient-to-position));
}
@supports (color: color-mix(in lab, red, red)) {
.from-cyan-500\\/50 {
--tw-gradient-from: color-mix(in oklab, var(--color-cyan-500) 50%, transparent);
}
}
:root, :host {
--color-cyan-500: oklch(71.5% .143 215.221);
}
@supports (((-webkit-hyphens: none)) and (not (margin-trim: 1lh))) or ((-moz-orient: inline) and (not (color: rgb(from red r g b)))) {
@layer base {
*, :before, :after, ::backdrop {
--tw-gradient-position: initial;
--tw-gradient-from: #0000;
--tw-gradient-via: #0000;
--tw-gradient-to: #0000;
--tw-gradient-stops: initial;
--tw-gradient-via-stops: initial;
--tw-gradient-from-position: 0%;
--tw-gradient-via-position: 50%;
--tw-gradient-to-position: 100%;
}
}
}
@property --tw-gradient-position {
syntax: "*";
inherits: false
}
@property --tw-gradient-from {
syntax: "<color>";
inherits: false;
initial-value: #0000;
}
@property --tw-gradient-via {
syntax: "<color>";
inherits: false;
initial-value: #0000;
}
@property --tw-gradient-to {
syntax: "<color>";
inherits: false;
initial-value: #0000;
}
@property --tw-gradient-stops {
syntax: "*";
inherits: false
}
@property --tw-gradient-via-stops {
syntax: "*";
inherits: false
}
@property --tw-gradient-from-position {
syntax: "<length-percentage>";
inherits: false;
initial-value: 0%;
}
@property --tw-gradient-via-position {
syntax: "<length-percentage>";
inherits: false;
initial-value: 50%;
}
@property --tw-gradient-to-position {
syntax: "<length-percentage>";
inherits: false;
initial-value: 100%;
}
```
## \* A note on `@property` polyfills and CSS modules
On Next.js, CSS module files are required to be _pure_, meaning that all
selectors must either be scoped to a class or an ID. Fortunatnyl for us,
this does not apply to `@property` rules which we've been using before
to initialize CSS variables.
However, since we're now bringing back the `@property` polyfills, that
would cause unexpected rules to be exported from the CSS file as this:
```css
@reference "tailwindcss";
.skew {
@apply skew-7;
}
```
Would turn to the following file:
```css
.skew {
/* … */
}
@supports (/*…*/) {
@layer base {
*, :before, :after, ::backdrop {
--tw-gradient-position: initial;
}
}
}
@property /* … */
```
Notice that this adds a `*` selector which is not considered pure.
Unfortunately there is no way for us to silence this warning or work
around it, as the dependency causing this errors
([`postcss-modules-local-by-default`](https://github.com/css-modules/postcss-modules-local-by-default))
is bundled into Next.js. To work around crashes, these polyfills will
not apply to CSS modules processed by the PostCSS extension for now.
## Testing on tailwindcss.com
To see the changes in effect, take a look at this screencast that
compares tailwindcss.com on iOS 15.5 with a version that has the patches
of this PR applied:
https://github.com/user-attachments/assets/1279d6f5-3c63-4f30-839c-198a789f4292
## Test plan
- Tested on tailwindcss.com via a preview build:
https://tailwindcss-com-git-legacy-browsers-tailwindlabs.vercel.app/
- Updated tests
- Ensure we also test on Chrome 111, Safari 16.4, Firefox 128 to
make sure we have no regressions. Also tested on Safari 16.4, 15.5, 18.0
|
||
Robin Malfait
|
bcf70990a7
|
Improve debug logs (#15303)
This PR improves the debug logs for the `@tailwindcss/postcss` integration. It uses custom instrumentation to provide a nested but detailed overview of where time is spent during the build process. The updated logs look like this: ``` [0.15ms] [@tailwindcss/postcss] src/app/geistsans_9fc57718.module.css [0.14ms] ↳ Quick bail check [0.02ms] [@tailwindcss/postcss] src/app/geistsans_9fc57718.module.css [0.01ms] ↳ Quick bail check [0.03ms] [@tailwindcss/postcss] src/app/geistmono_b9f59162.module.css [0.02ms] ↳ Quick bail check [0.12ms] [@tailwindcss/postcss] src/app/geistmono_b9f59162.module.css [0.11ms] ↳ Quick bail check [42.09ms] [@tailwindcss/postcss] src/app/globals.css [ 0.01ms] ↳ Quick bail check [12.12ms] ↳ Setup compiler [ 0.11ms] ↳ PostCSS AST -> Tailwind CSS AST [11.99ms] ↳ Create compiler [ 0.07ms] ↳ Register full rebuild paths [ 0.06ms] ↳ Setup scanner [ 7.51ms] ↳ Scan for candidates [ 5.86ms] ↳ Register dependency messages [ 5.88ms] ↳ Build utilities [ 8.34ms] ↳ Optimization [ 0.23ms] ↳ AST -> CSS [ 4.20ms] ↳ Lightning CSS [ 3.89ms] ↳ CSS -> PostCSS AST [ 1.97ms] ↳ Update PostCSS AST ``` |
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Robin Malfait
|
ab82efab7d
|
Expose timing information in debug mode (#14553)
This PR exposes when using the the `DEBUG` environment variable. This follows the `DEBUG` conventions where: - `DEBUG=1` - `DEBUG=true` - `DEBUG=*` - `DEBUG=tailwindcss` Will enable the debug information, but when using: - `DEBUG=0` - `DEBUG=false` - `DEBUG=-tailwindcss` It will not. This currently only exposes some timings related to: 1. Scanning for candidates 2. Building the CSS 3. Optimizing the CSS We can implement a more advanced version of this where we also expose more fine grained information such as the files we scanned, the amount of candidates we found and so on. But I believe that this will be enough to start triaging performance related issues. |
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Philipp Spiess
|
79794744a9
|
Resolve @import in core (#14446)
This PR brings `@import` resolution into Tailwind CSS core. This means that our clients (PostCSS, Vite, and CLI) no longer need to depend on `postcss` and `postcss-import` to resolve `@import`. Furthermore this simplifies the handling of relative paths for `@source`, `@plugin`, or `@config` in transitive CSS files (where the relative root should always be relative to the CSS file that contains the directive). This PR also fixes a plugin resolution bug where non-relative imports (e.g. directly importing node modules like `@plugin '@tailwindcss/typography';`) would not work in CSS files that are based in a different npm package. ### Resolving `@import` The core of the `@import` resolution is inside `packages/tailwindcss/src/at-import.ts`. There, to keep things performant, we do a two-step process to resolve imports. Imagine the following input CSS file: ```css @import "tailwindcss/theme.css"; @import "tailwindcss/utilities.css"; ``` Since our AST walks are synchronous, we will do a first traversal where we start a loading request for each `@import` directive. Once all loads are started, we will await the promise and do a second walk where we actually replace the AST nodes with their resolved stylesheets. All of this is recursive, so that `@import`-ed files can again `@import` other files. The core `@import` resolver also includes extensive test cases for [various combinations of media query and supports conditionals as well als layered imports](https://developer.mozilla.org/en-US/docs/Web/CSS/@import). When the same file is imported multiple times, the AST nodes are duplicated but duplicate I/O is avoided on a per-file basis, so this will only load one file, but include the `@theme` rules twice: ```css @import "tailwindcss/theme.css"; @import "tailwindcss/theme.css"; ``` ### Adding a new `context` node to the AST One limitation we had when working with the `postcss-import` plugin was the need to do an additional traversal to rewrite relative `@source`, `@plugin`, and `@config` directives. This was needed because we want these paths to be relative to the CSS file that defines the directive but when flattening a CSS file, this information is no longer part of the stringifed CSS representation. We worked around this by rewriting the content of these directives to be relative to the input CSS file, which resulted in added complexity and caused a lot of issues with Windows paths in the beginning. Now that we are doing the `@import` resolution in core, we can use a different data structure to persist this information. This PR adds a new `context` node so that we can store arbitrary context like this inside the Ast directly. This allows us to share information with the sub tree _while doing the Ast walk_. Here's an example of how the new `context` node can be used to share information with subtrees: ```ts const ast = [ rule('.foo', [decl('color', 'red')]), context({ value: 'a' }, [ rule('.bar', [ decl('color', 'blue'), context({ value: 'b' }, [ rule('.baz', [decl('color', 'green')]), ]), ]), ]), ] walk(ast, (node, { context }) => { if (node.kind !== 'declaration') return switch (node.value) { case 'red': assert(context.value === undefined) case 'blue': assert(context.value === 'a') case 'green': assert(context.value === 'b') } }) ``` In core, we use this new Ast node specifically to persist the `base` path of the current CSS file. We put the input CSS file `base` at the root of the Ast and then overwrite the `base` on every `@import` substitution. ### Removing the dependency on `postcss-import` Now that we support `@import` resolution in core, our clients no longer need a dependency on `postcss-import`. Furthermore, most dependencies also don't need to know about `postcss` at all anymore (except the PostCSS client, of course!). This also means that our workaround for rewriting `@source`, the `postcss-fix-relative-paths` plugin, can now go away as a shared dependency between all of our clients. Note that we still have it for the PostCSS plugin only, where it's possible that users already have `postcss-import` running _before_ the `@tailwindcss/postcss` plugin. Here's an example of the changes to the dependencies for our Vite client ✨ : <img width="854" alt="Screenshot 2024-09-19 at 16 59 45" src="https://github.com/user-attachments/assets/ae1f9d5f-d93a-4de9-9244-61af3aff1237"> ### Performance Since our Vite and CLI clients now no longer need to use `postcss` at all, we have also measured a significant improvement to the initial build times. For a small test setup that contains only a hand full of files (nothing super-complex), we measured an improvement in the **3.5x** range: <img width="1334" alt="Screenshot 2024-09-19 at 14 52 49" src="https://github.com/user-attachments/assets/06071fb0-7f2a-4de6-8ec8-f202d2cc78e5"> The code for this is in the commit history if you want to reproduce the results. The test was based on the Vite client. ### Caveats One thing to note is that we previously relied on finding specific symbols in the input CSS to _bail out of Tailwind processing completely_. E.g. if a file does not contain a `@tailwind` or `@apply` directive, it can never be a Tailwind file. Since we no longer have a string representation of the flattened CSS file, we can no longer do this check. However, the current implementation was already inconsistent with differences on the allowed symbol list between our clients. Ideally, Tailwind CSS should figure out wether a CSS file is a Tailwind CSS file. This, however, is left as an improvement for a future API since it goes hand-in-hand with our planned API changes for the core `tailwindcss` package. --------- Co-authored-by: Jordan Pittman <jordan@cryptica.me> |
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Philipp Spiess
|
a3a16e64d2
|
Fix a crash with older Node.js versions (#14342)
Closes #14341 --------- Co-authored-by: Jordan Pittman <jordan@cryptica.me> |
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|
Jordan Pittman
|
52012d90d7
|
Support loading config files via @config (#14239)
In Tailwind v4 the CSS file is the main entry point to your project and is generally configured via `@theme`. However, given that all v3 projects were configured via a `tailwind.config.js` file we definitely need to support those. This PR adds support for loading existing Tailwind config files by adding an `@config` directive to the CSS — similar to how v3 supported multiple config files except that this is now _required_ to use a config file. You can load a config file like so: ``` @import "tailwindcss"; @config "./path/to/tailwind.config.js"; ``` A few notes: - Both CommonJS and ESM config files are supported (loaded directly via `import()` in Node) - This is not yet supported in Intellisense or Prettier — should hopefully land next week - TypeScript is **not yet** supported in the config file — this will be handled in a future PR. --------- Co-authored-by: Philipp Spiess <hello@philippspiess.com> Co-authored-by: Adam Wathan <adam.wathan@gmail.com> Co-authored-by: Robin Malfait <malfait.robin@gmail.com> |