fix(nuxt): Keep sourcesContent in Nuxt 5 server source maps

Nitro's source map minification runs after the bundler writes the maps.
On Nitro 3 it deletes sourcesContent, which overrides the module's
sourcemapExcludeSources: false. Set nitro.experimental.sourcemapMinify
to false so Sentry can show the server source.

Fixes #25322

Author: s1gr1d

dev-packages/e2e-tests/test-applications/nuxt-5-sourcemaps/assert-build.ts

@@ -162,9 +162,9 @@ const containsMarker = (marker: string): boolean =>
 // Vite builds the client and Nitro builds the server. Counting bundles would still pass with either
 // plugin dropped, so each side is pinned to a marker only that side's source supplies.
 assert.ok(containsMarker(CLIENT_MARKER), 'Expected an uploaded sourcemap carrying the client source (Vite plugin)');
-// TODO: Nitro 3 builds the server with Rolldown, and the uploaded server maps carry no `sourcesContent`: the
-// module's `sourcemapExcludeSources: false` does not reach that build. Assert the server marker when that is fixed:
-// assert.ok(containsMarker(SERVER_MARKER), 'Expected an uploaded sourcemap carrying the server source (Rollup plugin)');
+// Nitro 3 deletes `sourcesContent` from the server maps unless `experimental.sourcemapMinify` is `false`. The module
+// sets it to `false`, which is the only reason this marker survives into `sourcesContent`.
+assert.ok(containsMarker(SERVER_MARKER), 'Expected an uploaded sourcemap carrying the server source (Rollup plugin)');
 
 // `rewriteSources` normalizes `../../../foo` to `./foo` so paths stay resolvable in Sentry.
 const unnormalizedSources = [...new Set(sourcemaps.flatMap(map => map.sourcemap.sources ?? []))].filter(

packages/nuxt/src/vite/sourceMaps.ts

@@ -324,7 +324,7 @@ export function changeNuxtSourceMapSettings(
 }
 
 /** Logs warnings about potentially conflicting source map settings.
- *  Configures `sourcemapExcludeSources` in Nitro to make source maps usable in Sentry.
+ *  Configures `sourcemapExcludeSources` and `sourcemapMinify` in Nitro to make source maps usable in Sentry.
  *
  * only exported for testing
  */
@@ -364,10 +364,13 @@ export function validateNitroSourceMapSettings(
   }
 
   nitroConfig.rollupConfig.output.sourcemapExcludeSources = false;
+  // Nitro's source map minification runs after the bundler wrote the maps: it clears `mappings` of maps with
+  // `node_modules` sources, and Nitro 3 also deletes `sourcesContent`, which overrides `sourcemapExcludeSources`.
+  nitroConfig.experimental = { ...nitroConfig.experimental, sourcemapMinify: false };
   if (isDebug) {
     // eslint-disable-next-line no-console
     console.log(
-      '[Sentry] Set `sourcemapExcludeSources: false` in the Nuxt config (`nitro.rollupConfig.output`). Source maps will now include the actual code to be able to un-minify code snippets in Sentry.',
+      '[Sentry] Set `sourcemapExcludeSources: false` (`nitro.rollupConfig.output`) and `sourcemapMinify: false` (`nitro.experimental`) in the Nuxt config. Source maps will now include the actual code to be able to un-minify code snippets in Sentry.',
     );
   }
 }

packages/nuxt/test/vite/sourceMaps.test.ts

@@ -328,6 +328,7 @@ describe('validate sourcemap settings', () => {
       rollupConfig?: {
         output?: { sourcemap?: SourceMapSetting; sourcemapExcludeSources?: boolean };
       };
+      experimental?: { asyncContext?: boolean; sourcemapMinify?: false };
     };
     type MinimalNuxtConfig = {
       options: { sourcemap?: SourceMapSetting | { server?: SourceMapSetting; client?: SourceMapSetting } };
@@ -363,6 +364,14 @@ describe('validate sourcemap settings', () => {
       expect(nitroConfig?.rollupConfig?.output?.sourcemapExcludeSources).toBe(false);
     });
 
+    it("should disable Nitro's source map minification and keep other experimental options", () => {
+      const nitroConfig = { ...getNitroConfig(true), experimental: { asyncContext: true } };
+
+      validateNitroSourceMapSettings(getNuxtConfig(true), nitroConfig, { debug: true });
+
+      expect(nitroConfig.experimental).toEqual({ asyncContext: true, sourcemapMinify: false });
+    });
+
     it('should not show console.warn when rollup sourcemap is undefined', () => {
       const nitroConfig = getNitroConfig(true);