fix: resolve .css.ts files instead of externalizing them (#173)

sxzz · web-flow · commit e52624a5a33d · 2026-01-30T08:30:45.000+08:00
* fix: move css externalization after dts resolution check CSS imports should only be externalized if they cannot be resolved as DTS files. This ensures CSS-related files are properly handled after attempting DTS resolution first. * fix: resolve .css.ts files instead of externalizing them Move the CSS externalization guard to after resolution so that .css.ts files (e.g. vanilla-extract) are properly resolved and bundled into declarations, while real .css imports remain externalized. Closes #136
diff --git a/src/resolver.ts b/src/resolver.ts
@@ -53,12 +53,6 @@ export function createDtsResolvePlugin({
           moduleSideEffects: sideEffects,
         }
 
-        // Guard: Externalize non-code imports
-        if (RE_CSS.test(id)) {
-          debug('Externalizing css import:', id)
-          return external
-        }
-
         // Get Rolldown's resolution first for fallback and policy checks
         const rolldownResolution = await this.resolve(id, importer, options)
         debug(
@@ -86,6 +80,11 @@ export function createDtsResolvePlugin({
 
         // If resolution failed, error or externalize
         if (!dtsResolution) {
+          if (RE_CSS.test(id)) {
+            debug('Externalizing css import:', id)
+            return external
+          }
+
           debug('Unresolvable dts import:', id, 'from', importer)
 
           const isFileImport = isFilePath(id)
diff --git a/tests/__snapshots__/index.test.ts.snap b/tests/__snapshots__/index.test.ts.snap
@@ -70,6 +70,14 @@ declare const shared1 = "shared1";
 export { shared1 as t };"
 `;
 
+exports[`css.ts files 1`] = `
+"// index.d.ts
+//#region tests/fixtures/css-ts/file.css.d.ts
+declare const myClass: string;
+//#endregion
+export { myClass };"
+`;
+
 exports[`cyclic import 1`] = `
 "// a-B8uCZscZ.d.ts
 //#region b.d.ts
@@ -359,6 +367,14 @@ type LibType = import_stub_lib.LibType;
 export { type LibType };"
 `;
 
+exports[`real css imports are externalized 1`] = `
+"// index.d.ts
+//#region tests/fixtures/css-real/index.d.ts
+declare const foo: number;
+//#endregion
+export { foo };"
+`;
+
 exports[`resolve dts 1`] = `
 "// index.d.ts
 //#region tests/fixtures/resolve-dts/mod.d.ts
diff --git a/tests/fixtures/css-real/index.ts b/tests/fixtures/css-real/index.ts
@@ -0,0 +1,2 @@
+import './styles.css'
+export const foo: number = 1
diff --git a/tests/fixtures/css-real/styles.css b/tests/fixtures/css-real/styles.css
@@ -0,0 +1,3 @@
+.main {
+  color: blue;
+}
diff --git a/tests/fixtures/css-ts/file.css.ts b/tests/fixtures/css-ts/file.css.ts
@@ -0,0 +1 @@
+export const myClass: string = 'foo'
diff --git a/tests/fixtures/css-ts/index.ts b/tests/fixtures/css-ts/index.ts
@@ -0,0 +1 @@
+export * from './file.css'
diff --git a/tests/index.test.ts b/tests/index.test.ts
@@ -529,6 +529,25 @@ test('tsgo with custom path', async () => {
   expect(snapshot).toMatchSnapshot()
 })
 
+// https://github.com/sxzz/rolldown-plugin-dts/issues/136
+test('css.ts files', async () => {
+  const root = path.resolve(dirname, 'fixtures/css-ts')
+  const { snapshot } = await rolldownBuild(path.resolve(root, 'index.ts'), [
+    dts({ emitDtsOnly: true }),
+  ])
+  expect(snapshot).toMatchSnapshot()
+})
+
+// https://github.com/rolldown/tsdown/issues/170
+test('real css imports are externalized', async () => {
+  const root = path.resolve(dirname, 'fixtures/css-real')
+  const { snapshot } = await rolldownBuild(path.resolve(root, 'index.ts'), [
+    dts({ emitDtsOnly: true }),
+  ])
+  expect(snapshot).toMatchSnapshot()
+  expect(snapshot).not.toContain('.main')
+})
+
 test('sub namespace', async () => {
   const { snapshot } = await rolldownBuild(
     path.resolve(dirname, 'fixtures/sub-namespace.ts'),

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	`+import './styles.css'`
	`2`	`+export const foo: number = 1`