Fix v4 theme reloading on Windows (tailwindlabs#960)

We now normalize case of windows drive letters of watched files because we may recieve a path that has `C:` at the start of a path in some places and `c:` in others because they’re coming from different sources (filesystem vs VS Code file watching notifications).

Author: thecrypticace

packages/tailwindcss-language-server/src/tw.ts

@@ -40,7 +40,7 @@ import resolveFrom from './util/resolveFrom'
 import * as parcel from './watcher/index.js'
 import { equal } from '@tailwindcss/language-service/src/util/array'
 import { CONFIG_GLOB, CSS_GLOB, PACKAGE_LOCK_GLOB } from './lib/constants'
-import { clearRequireCache, isObject, changeAffectsFile } from './utils'
+import { clearRequireCache, isObject, changeAffectsFile, normalizeDriveLetter } from './utils'
 import { DocumentService } from './documents'
 import { createProjectService, type ProjectService } from './projects'
 import { type SettingsCache, createSettingsCache } from './config'
@@ -273,6 +273,7 @@ export class TW {
 
       changeLoop: for (let change of changes) {
         let normalizedFilename = normalizePath(change.file)
+        normalizedFilename = normalizeDriveLetter(normalizedFilename)
 
         for (let ignorePattern of ignore) {
           let isIgnored = picomatch(ignorePattern, { dot: true })
@@ -312,6 +313,8 @@ export class TW {
             ...project.projectConfig.config.entries.map((entry) => entry.path),
           ]
 
+          reloadableFiles = reloadableFiles.map(normalizeDriveLetter)
+
           if (!changeAffectsFile(normalizedFilename, reloadableFiles)) continue
 
           needsSoftRestart = true

packages/tailwindcss-language-server/src/utils.ts

@@ -70,6 +70,17 @@ export function dirContains(dir: string, file: string): boolean {
   return !!relative && !relative.startsWith('..') && !path.isAbsolute(relative)
 }
 
+const WIN_DRIVE_LETTER = /^([a-zA-Z]):/
+
+/**
+ * Windows drive letters are case-insensitive and we may get them as either
+ * lower or upper case. This function normalizes the drive letter to uppercase
+ * to be consistent with the rest of the codebase.
+ */
+export function normalizeDriveLetter(filepath: string) {
+  return filepath.replace(WIN_DRIVE_LETTER, (_, letter) => letter.toUpperCase() + ':')
+}
+
 export function changeAffectsFile(change: string, files: string[]): boolean {
   for (let file of files) {
     if (change === file || dirContains(change, file)) {