Add support for @plugin and @config in v4 (#316)

* Support `@plugin` and `@config` in v4

* Rework fixture installation script

* Add basic v4 test

* Add v4 configs test

* Update changelog

Author: thecrypticace

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 - Improved performance with large Svelte, Liquid, and Angular files ([#312](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/pull/312))
+- Add support for @plugin and @config in v4 ([#316](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/pull/316))
 
 ## [0.6.6] - 2024-08-09
 

scripts/install-fixture-deps.js

@@ -3,26 +3,23 @@ import * as fs from 'node:fs/promises'
 import * as path from 'node:path'
 import { fileURLToPath } from 'node:url'
 import { promisify } from 'node:util'
-
-const execAsync = promisify(exec)
+import glob from 'fast-glob'
 
 const __dirname = path.dirname(fileURLToPath(import.meta.url))
 
-let fixturesDir = path.resolve(__dirname, '../tests/fixtures')
-let fixtureDirs = await fs.readdir(fixturesDir)
-let fixtures = fixtureDirs.map((name) => path.join(fixturesDir, name))
+const fixtures = glob.sync(
+  ['tests/fixtures/*/package.json', 'tests/fixtures/v4/*/package.json'],
+  {
+    cwd: path.resolve(__dirname, '..'),
+  },
+)
+
+const execAsync = promisify(exec)
 
 await Promise.all(
   fixtures.map(async (fixture) => {
-    let exists = await fs.access(path.join(fixture, 'package.json')).then(
-      () => true,
-      () => false,
-    )
-
-    if (!exists) return
-
     console.log(`Installing dependencies for ${fixture}`)
 
-    await execAsync('npm install', { cwd: fixture })
+    await execAsync('npm install', { cwd: path.dirname(fixture) })
   }),
 )

src/config.ts

@@ -18,7 +18,7 @@ import loadConfigFallback from 'tailwindcss/loadConfig'
 import resolveConfigFallback from 'tailwindcss/resolveConfig'
 import type { RequiredConfig } from 'tailwindcss/types/config.js'
 import { expiringMap } from './expiring-map.js'
-import { resolveIn } from './resolve'
+import { resolveFrom, resolveIn } from './resolve'
 import type { ContextContainer } from './types'
 
 let localRequire = createRequire(import.meta.url)
@@ -147,6 +147,37 @@ async function loadTailwindConfig(
   }
 }
 
+/**
+ * Create a loader function that can load plugins and config files relative to
+ * the CSS file that uses them. However, we don't want missing files to prevent
+ * everything from working so we'll let the error handler decide how to proceed.
+ *
+ * @param {object} param0
+ * @returns
+ */
+function createLoader<T>({
+  filepath,
+  onError,
+}: {
+  filepath: string
+  onError: (id: string, error: unknown) => T
+}) {
+  let baseDir = path.dirname(filepath)
+  let cacheKey = `${+Date.now()}`
+
+  return async function loadFile(id: string) {
+    try {
+      let resolved = resolveFrom(baseDir, id)
+      let url = pathToFileURL(resolved)
+      url.searchParams.append('t', cacheKey)
+
+      return await import(url.href).then((m) => m.default ?? m)
+    } catch (err) {
+      return onError(id, err)
+    }
+  }
+}
+
 async function loadV4(
   baseDir: string,
   pkgDir: string,
@@ -172,9 +203,23 @@ async function loadV4(
   // Load the design system and set up a compatible context object that is
   // usable by the rest of the plugin
   let design = await tw.__unstable__loadDesignSystem(result.css, {
-    loadPlugin() {
-      return () => {}
-    },
+    loadPlugin: createLoader({
+      filepath: entryPoint,
+      onError(id, err) {
+        console.error(`Unable to load plugin: ${id}`, err)
+
+        return () => {}
+      },
+    }),
+
+    loadConfig: createLoader({
+      filepath: entryPoint,
+      onError(id, err) {
+        console.error(`Unable to load config: ${id}`, err)
+
+        return {}
+      },
+    }),
   })
 
   return {

src/resolve.ts

@@ -1,4 +1,5 @@
 import { createRequire as req } from 'node:module'
+import resolveFrom from 'resolve-from'
 import { expiringMap } from './expiring-map'
 
 const localRequire = req(import.meta.url)
@@ -45,3 +46,5 @@ function freshMaybeResolve(name: string) {
     return null
   }
 }
+
+export { resolveFrom }

tests/fixtures.test.ts

@@ -62,6 +62,17 @@ let fixtures = [
     dir: 'custom-jsx',
     ext: 'jsx',
   },
+
+  {
+    name: 'v4: basic formatting',
+    dir: 'v4/basic',
+    ext: 'html',
+  },
+  {
+    name: 'v4: configs and plugins',
+    dir: 'v4/configs',
+    ext: 'html',
+  },
 ]
 
 let configs = [

tests/fixtures/v4/basic/app.css

@@ -0,0 +1,5 @@
+@import 'tailwindcss';
+
+@theme {
+  --color-tomato: tomato;
+}

tests/fixtures/v4/basic/index.html

@@ -0,0 +1 @@
+<div class="sm:bg-tomato bg-red-500"></div>

tests/fixtures/v4/basic/output.html

@@ -0,0 +1 @@
+<div class="bg-red-500 sm:bg-tomato"></div>

tests/fixtures/v4/basic/package-lock.json

@@ -0,0 +1,8 @@
+{
+  "dependencies": {
+    "tailwindcss": "^4.0.0-alpha.23"
+  },
+  "prettier": {
+    "tailwindEntryPoint": "./app.css"
+  }
+}