Handle quotes in @plugin, @config, and @source

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Don't augment global Prettier `ParserOptions` and `RequiredOptions` types ([#354](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/pull/354))
 - Drop support for `prettier-plugin-import-sort` ([#385](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/pull/385))
+- Format quotes in `@source`, `@plugin`, and `@config` ([#387](https://github.com/tailwindlabs/prettier-plugin-tailwindcss/pull/387))
 
 ## [0.6.14] - 2025-07-09
 

src/index.ts

@@ -786,7 +786,38 @@ function transformJavaScript(
 }
 
 function transformCss(ast: any, { env }: TransformerContext) {
+  // `parseValue` inside Prettier's CSS parser is private API so we have to
+  // produce the same result by parsing an import statement with the same params
+  function tryParseAtRuleParams(name: string, params: any) {
+    // It might already be an object or array. Could happen in the future if
+    // Prettier decides to start parsing these.
+    if (typeof params !== 'string') return params
+
+    // Otherwise we let prettier re-parse the params into its custom value AST
+    // based on postcss-value parser.
+    try {
+      let parser = base.parsers.css
+      let root = parser.parse(`@import ${params};`, env.options)
+
+      return root.nodes[0].params
+    } catch (err) {
+      console.warn(`[prettier-plugin-tailwindcss] Unable to parse at rule`)
+      console.warn({ name, params })
+      console.warn(err)
+    }
+
+    return params
+  }
+
   ast.walk((node: any) => {
+    if (
+      node.name === 'plugin' ||
+      node.name === 'config' ||
+      node.name === 'source'
+    ) {
+      node.params = tryParseAtRuleParams(node.name, node.params)
+    }
+
     if (node.type === 'css-atrule' && node.name === 'apply') {
       let isImportant = /\s+(?:!important|#{(['"]*)!important\1})\s*$/.test(
         node.params,

tests/tests.ts

@@ -43,6 +43,14 @@ let css: TestEntry[] = [
     '@apply p-0\n   sm:p-0;',
     { tailwindPreserveWhitespace: true },
   ],
+
+  // Quote conversion for custom at-rules
+  [`@import "./file.css";`, `@import './file.css';`],
+  [`@plugin "./file.js";`, `@plugin './file.js';`],
+  [`@config "./file.js";`, `@config './file.js';`],
+  [`@source "./file.js";`, `@source './file.js';`],
+  [`@source not "./file.js";`, `@source not './file.js';`],
+  [`@source inline("./file.js");`, `@source inline('./file.js');`],
 ]
 
 export let javascript: TestEntry[] = [