Fix issue when require()-ing packages that resolve to paths containing #

packages/tailwindcss-language-server/src/testing/index.ts

@@ -11,12 +11,13 @@ export interface TestUtils {
 
 export interface Storage {
   /** A list of files and their content */
-  [filePath: string]: string | Uint8Array
+  [filePath: string]: string | Uint8Array | { [IS_A_SYMLINK]: true; filepath: string }
 }
 
 export interface TestConfig<Extras extends {}> {
   name: string
   fs?: Storage
+  debug?: boolean
   prepare?(utils: TestUtils): Promise<Extras>
   handle(utils: TestUtils & Extras): void | Promise<void>
 
@@ -56,6 +57,8 @@ async function setup<T>(config: TestConfig<T>): Promise<TestUtils> {
 
     if (path.sep === '\\') return
 
+    if (config.debug) return
+
     // Remove the directory on *nix systems. Recursive removal on Windows will
     // randomly fail b/c its slow and buggy.
     await fs.rm(doneDir, { recursive: true })
@@ -66,6 +69,14 @@ async function setup<T>(config: TestConfig<T>): Promise<TestUtils> {
   }
 }
 
+const IS_A_SYMLINK = Symbol('is-a-symlink')
+export const symlinkTo = function (filepath: string) {
+  return {
+    [IS_A_SYMLINK]: true as const,
+    filepath,
+  }
+}
+
 async function prepareFileSystem(base: string, storage: Storage) {
   // Create a temporary directory to store the test files
   await fs.mkdir(base, { recursive: true })
@@ -74,6 +85,13 @@ async function prepareFileSystem(base: string, storage: Storage) {
   for (let [filepath, content] of Object.entries(storage)) {
     let fullPath = path.resolve(base, filepath)
     await fs.mkdir(path.dirname(fullPath), { recursive: true })
+
+    if (typeof content === 'object' && IS_A_SYMLINK in content) {
+      let target = path.resolve(base, content.filepath)
+      await fs.symlink(target, fullPath)
+      continue
+    }
+
     await fs.writeFile(fullPath, content, { encoding: 'utf-8' })
   }
 }

packages/tailwindcss-language-server/src/util/resolveFrom.ts

@@ -56,5 +56,17 @@ export function resolveFrom(from?: string, id?: string): string {
 
   let result = resolver.resolveSync({}, from, id)
   if (result === false) throw Error()
+
+  // The `enhanced-resolve` package supports resolving paths with fragment
+  // identifiers. For example, it can resolve `foo/bar#baz` to `foo/bar.js`
+  // However, it's also possible that a path contains a `#` character as part
+  // of the path itself. For example, `foo#bar` might point to a file named
+  // `foo#bar.js`. The resolver distinguishes between these two cases by
+  // escaping the `#` character with a NUL byte when it's part of the path.
+  //
+  // Since the real path doesn't actually contain NUL bytes, we need to remove
+  // them to get the correct path otherwise readFileSync will throw an error.
+  result = result.replace(/\0(.)/g, '$1')
+
   return result
 }

packages/tailwindcss-language-server/tests/env/v4.test.js

@@ -1,7 +1,7 @@
 // @ts-check
 
 import { expect } from 'vitest'
-import { css, defineTest, html, js, json } from '../../src/testing'
+import { css, defineTest, html, js, json, symlinkTo } from '../../src/testing'
 import dedent from 'dedent'
 import { createClient } from '../utils/client'
 
@@ -666,3 +666,89 @@ defineTest({
     })
   },
 })
+
+defineTest({
+  // This test *always* passes inside Vitest because our custom version of
+  // `Module._resolveFilename` is not called. Our custom implementation is
+  // using enhanced-resolve under the hood which is affected by the `#`
+  // character issue being considered a fragment identifier.
+  //
+  // This most commonly happens when dealing with PNPM packages that point
+  // to a specific commit hash of a git repository.
+  //
+  // To simulate this, we need to:
+  // - Add a local package to package.json
+  // - Symlink that local package to a directory with `#` in the name
+  // - Then run the test in a separate process (`spawn` mode)
+  //
+  // We can't use `file:./a#b` because NPM considers `#` to be a fragment
+  // identifier and will not resolve the path the way we need it to.
+  name: 'v3: require() works when path is resolved to contain a `#`',
+  fs: {
+    'package.json': json`
+      {
+        "dependencies": {
+          "tailwindcss": "3.4.17",
+          "some-pkg": "file:./packages/some-pkg"
+        }
+      }
+    `,
+    'tailwind.config.js': js`
+      module.exports = {
+        presets: [require('some-pkg/config/tailwind.config.js').default]
+      }
+    `,
+    'packages/some-pkg': symlinkTo('packages/some-pkg#c3f1e'),
+    'packages/some-pkg#c3f1e/package.json': json`
+      {
+        "name": "some-pkg",
+        "version": "1.0.0",
+        "main": "index.js"
+      }
+    `,
+    'packages/some-pkg#c3f1e/config/tailwind.config.js': js`
+      export default {
+        plugins: [
+          function ({ addUtilities }) {
+            addUtilities({
+              '.example': {
+                color: 'red',
+              },
+            })
+          }
+        ]
+      }
+    `,
+  },
+  prepare: async ({ root }) => ({
+    client: await createClient({
+      root,
+      mode: 'spawn',
+    }),
+  }),
+  handle: async ({ client }) => {
+    let document = await client.open({
+      lang: 'html',
+      text: '<div class="example">',
+    })
+
+    // <div class="example">
+    //             ^
+    let hover = await document.hover({ line: 0, character: 13 })
+
+    expect(hover).toEqual({
+      contents: {
+        language: 'css',
+        value: dedent`
+          .example {
+            color: red;
+          }
+        `,
+      },
+      range: {
+        start: { line: 0, character: 12 },
+        end: { line: 0, character: 19 },
+      },
+    })
+  },
+})

packages/vscode-tailwindcss/CHANGELOG.md

@@ -2,7 +2,7 @@
 
 ## Prerelease
 
-- Nothing yet!
+- Don't throw when requiring() packages that resolve to a path containing a `#` character ([#1235](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1235))
 
 # 0.14.7