Add targeted fix for stylesheets named tailwindcss.css (#1517)

Fixes #1427

Author: thecrypticace

packages/tailwindcss-language-server/src/project-locator.test.ts

@@ -588,6 +588,22 @@ testLocator({
   ],
 })
 
+testLocator({
+  name: 'A stylesheet can be named tailwindcss.css',
+  fs: {
+    'src/tailwindcss.css': css`
+      @import 'tailwindcss';
+    `,
+  },
+  expected: [
+    {
+      version: '4.1.18 (bundled)',
+      config: '/src/tailwindcss.css',
+      content: [],
+    },
+  ],
+})
+
 // ---
 
 function testLocator({

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

@@ -170,6 +170,17 @@ export async function createResolver(opts: ResolverOptions): Promise<Resolver> {
     preferRelative: true,
   })
 
+  let absoluteCssResolver = ResolverFactory.createResolver({
+    fileSystem,
+    extensions: ['.css'],
+    mainFields: ['style'],
+    conditionNames: ['style'],
+    pnpApi,
+
+    // Used as a fallback when a file ends up importing itself
+    preferRelative: false,
+  })
+
   async function resolveId(
     resolver: BaseResolver,
     id: string,
@@ -235,7 +246,22 @@ export async function createResolver(opts: ResolverOptions): Promise<Resolver> {
   }
 
   async function resolveCssId(id: string, base: string): Promise<string> {
-    return (await resolveId(cssResolver, id, base)) || id
+    // If the ID matches `tailwindcss` exactly we tell the CSS resolver to
+    // ignore relative file paths. This ensures that Tailwind CSS itself is
+    // found even when a stylesheet named `tailwindcss.css` exists.
+    //
+    // If someone needs to import that stylesheet it must be done by:
+    // - relative path: `@import "./tailwindcss"`
+    // - adding an extension: `@import "tailwindcss.css"`
+    //
+    // Ideally this code would only be in place if the _importer_ is
+    // `tailwindcss.css` but that data is not available. Only the base
+    // path is so we enable it all the time.
+    //
+    // https://github.com/tailwindlabs/tailwindcss-intellisense/issues/1427
+    let resolver = id === 'tailwindcss' ? absoluteCssResolver : cssResolver
+
+    return (await resolveId(resolver, id, base)) || id
   }
 
   // Takes a path which may or may not be complete and returns the aliased path

packages/vscode-tailwindcss/CHANGELOG.md

@@ -5,6 +5,7 @@
 - Add a source to all emitted diagnostics ([#1491](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1491))
 - Improve performance in large files ([#1507](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1507))
 - Improve utility lookup performance when using v4 ([#1509](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1509))
+- Fix project initalization when stylesheet is named `tailwindcss.css` ([#1517](https://github.com/tailwindlabs/tailwindcss-intellisense/pull/1517))
 
 ## 0.14.29