fix: update from rolldown-vite to vite-8 beta (#1246)

* fix: update from rolldown-vite to vite-8 beta

* change ci workflow to use vite 8 beta

* adapt testcases for vite 8 beta

* work around sourcemap bug in vite-8 beta

* work around remaining test fails

* try to convince ci on github to install vite-8.0.0-beta.1

* persist workaround for sourcemap issue

Author: dominikg

.changeset/nine-lizards-design.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/vite-plugin-svelte': patch
+---
+
+Update experimental support for rolldown-vite to vite 8 beta

.github/workflows/ci.yml

@@ -94,10 +94,10 @@ jobs:
             os: ubuntu-latest
             vite: 'baseline'
             svelte: 'baseline'
-          # future test with rolldown-vite
+          # future test with vite-8-beta
           - node: 24
             os: ubuntu-latest
-            vite: 'rolldown-vite'
+            vite: '8-beta'
             svelte: 'current'
     steps:
       - uses: actions/checkout@v5
@@ -128,17 +128,17 @@ jobs:
         run: |
           pnpm update -r --no-save svelte@5.0.0
           pnpm ls svelte
-      - name: update vite to rolldown-vite
-        if: matrix.vite == 'rolldown-vite'
+      - name: update vite to vite-8-beta
+        if: matrix.vite == '8-beta'
         run: |
-          pnpm update -r --no-save vite@npm:rolldown-vite@latest
-          pnpm ls rolldown-vite
+          pnpm update -r --no-save vite@beta
+          pnpm ls vite
       - name: install playwright chromium
         run: pnpm playwright install chromium
       - name: run tests
         run: pnpm test
-      - name: check-types with rolldown-vite
-        if: matrix.vite == 'rolldown-vite'
+      - name: check-types with vite-8-beta
+        if: matrix.vite == '8-beta'
         run: pnpm check:types
       - name: archive tests temp directory
         if: failure()

.prettierrc.js

@@ -26,7 +26,8 @@ export default {
 				'packages/e2e-tests/dynamic-compile-options/src/components/A.svelte',
 				'packages/playground/big/src/pages/**', // lots of generated files
 				'packages/e2e-tests/scan-deps/src/Svelte*.svelte', // various syntax tests that require no format
-				'**/.vite-inspect/**'
+				'**/.vite-inspect/**',
+				'packages/e2e-tests/_test_dependencies/**/*.svelte' // TODO remove after sourcemap bug is fixed
 			],
 			options: {
 				rangeEnd: 0

packages/e2e-tests/_test_dependencies/svelte-exports-simple/src/components/Dependency.svelte

@@ -2,7 +2,7 @@
 	const label = 'dependency-import';
 	import * as cjsOnly from 'e2e-test-dep-cjs-only';
 	const { cjs } = cjsOnly;
-</script>
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */ </script>
 
 <div id="dependency-import"><span class="label">{label}</span></div>
 <div id="sticky-dep" class="sticky-dep">sticky-dep</div>

packages/e2e-tests/_test_dependencies/svelte-hybrid/src/components/Dependency.svelte

@@ -2,7 +2,7 @@
 	const label = 'dependency-import';
 	import * as cjsOnly from 'e2e-test-dep-cjs-only';
 	const { cjs } = cjsOnly;
-</script>
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */ </script>
 
 <div id="dependency-import"><span class="label">{label}</span></div>
 <div id="sticky-dep" class="sticky-dep">sticky-dep</div>

packages/e2e-tests/_test_dependencies/svelte-module/src/counter/Counter.svelte

@@ -2,7 +2,7 @@
 	import { createCounter } from './Counter.svelte.js';
 	const counter = createCounter(0);
 	let localCounter = $state(0);
-</script>
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */ </script>
 
 <button onclick={counter.increment}>
 	count is {counter.count}

packages/e2e-tests/_test_dependencies/svelte-nested-workspace-devdep/src/components/Message.svelte

@@ -3,7 +3,8 @@
 	export let message = '';
 	import { cjs_and_esm } from 'e2e-test-dep-cjs-and-esm';
 	import 'e2e-test-dep-scss-only';
-</script>
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */
+ </script>
 
 <div {id}>{message}</div>
 <div id="cjs-and-esm">{cjs_and_esm()}</div>

packages/e2e-tests/_test_dependencies/svelte-nested/src/components/Message.svelte

@@ -3,7 +3,7 @@
 	export let message = '';
 	import { cjs_and_esm } from 'e2e-test-dep-cjs-and-esm';
 	import 'e2e-test-dep-scss-only';
-</script>
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */ </script>
 
 <div {id}>{message}</div>
 <div id="cjs-and-esm">{cjs_and_esm()}</div>

packages/e2e-tests/_test_dependencies/svelte-simple/src/components/Dependency.svelte

@@ -1,8 +1,10 @@
 <script>
-	const label = 'dependency-import';
 	import * as cjsOnly from 'e2e-test-dep-cjs-only';
+	const label = 'dependency-import';
 	const { cjs } = cjsOnly;
-</script>
+	// moving the following script close tag to column 0 triggers a bug in svelte sourcemap creation that prevents rolldown optimizer from processing the sourcemap
+	// TODO: move it back after fixed in svelte see https://github.com/sveltejs/svelte/pull/17167
+	/*  //TODO: move closing tag back to column zero after sourcemap bug is fixed */ </script>
 
 <div id="dependency-import"><span class="label">{label}</span></div>
 <div id="sticky-dep" class="sticky-dep">sticky-dep</div>

packages/e2e-tests/scan-deps/__tests__/scan-deps.spec.ts

@@ -1,15 +1,9 @@
-import { e2eServer, getText } from '~utils';
+import { getServerErrors, getText } from '~utils';
 import { describe, expect, it } from 'vitest';
 describe('vite import scan', () => {
 	it('should not fail to discover dependencies exported from script module', async () => {
 		// vite logs an error if scan fails but continues, so validate no errors logged
-		const errorLogs = e2eServer.logs.server.err.filter(
-			(line) =>
-				![
-					'Support for rolldown-vite in vite-plugin-svelte is experimental',
-					'See https://github.com/sveltejs/vite-plugin-svelte/issues/1143 for a list of known issues'
-				].some((ignore) => line.includes(ignore))
-		);
+		const errorLogs = getServerErrors();
 		expect(errorLogs.length, `unexpected errors:\n${errorLogs.join('\n')}`).toBe(0);
 	});
 	it('should work with exports from module context', async () => {