fix(solidstart): Support rolldownOptions in instrumentation file plugin

packages/solidstart/src/vite/buildInstrumentationFile.ts

@@ -16,11 +16,13 @@ export function makeBuildInstrumentationFilePlugin(options: SentrySolidStartPlug
     async config(config: UserConfig, { command }) {
       const instrumentationFilePath = options.instrumentation || './src/instrument.server.ts';
       const router = (config as UserConfig & { router: { target: string; name: string; root: string } }).router;
-      const build = config.build || {};
-      // SolidStart builds with vinxi's Vite, which predates `rolldownOptions`
+      // `rollupOptions` is a deprecated alias of `rolldownOptions` in Vite 8+, but the only option in older Vite.
+      // Returning both makes Vite 8 ignore `rollupOptions`, so only write back the one that is in use.
       // oxlint-disable-next-line typescript/no-deprecated
-      const rollupOptions = build.rollupOptions || {};
-      const input = [...((rollupOptions.input || []) as string[])];
+      const { rollupOptions, rolldownOptions, ...build } = config.build || {};
+      const bundlerOptionsKey = rolldownOptions ? 'rolldownOptions' : 'rollupOptions';
+      const bundlerOptions = rolldownOptions || rollupOptions || {};
+      const input = [...((bundlerOptions.input || []) as string[])];
 
       // plugin runs for client, server and sever-fns, we only want to run it for the server once.
       if (command !== 'build' || router.target !== 'server' || router.name === 'server-fns') {
@@ -46,9 +48,8 @@ export function makeBuildInstrumentationFilePlugin(options: SentrySolidStartPlug
         ...config,
         build: {
           ...build,
-          // oxlint-disable-next-line typescript/no-deprecated
-          rollupOptions: {
-            ...rollupOptions,
+          [bundlerOptionsKey]: {
+            ...bundlerOptions,
             input,
           },
         },

packages/solidstart/test/vite/buildInstrumentation.test.ts

@@ -63,6 +63,28 @@ describe('makeBuildInstrumentationFilePlugin()', () => {
     expect(config.build.rollupOptions.input).toContain('/some/project/path/src/myapp/instrument.server.ts');
   });
 
+  it('adds the instrumentation file to `rolldownOptions` if the config uses them', async () => {
+    const buildInstrumentationFilePlugin = makeBuildInstrumentationFilePlugin();
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+    // @ts-ignore - this is always defined and always a function
+    const config = await buildInstrumentationFilePlugin.config(
+      {
+        ...viteConfig,
+        build: {
+          rolldownOptions: {
+            input: ['/path/to/entry1.js'],
+          },
+        },
+      },
+      { command: 'build' },
+    );
+    expect(config.build.rolldownOptions.input).toEqual([
+      '/path/to/entry1.js',
+      '/some/project/path/src/instrument.server.ts',
+    ]);
+    expect(config.build).not.toHaveProperty('rollupOptions');
+  });
+
   it("doesn't add the instrumentation file for server function builds", async () => {
     const buildInstrumentationFilePlugin = makeBuildInstrumentationFilePlugin();
     // eslint-disable-next-line @typescript-eslint/ban-ts-comment