[build-sourcemaps] Sourcemap errors during prerender if experimental.enablePrerenderSourceMaps is enabled

.changeset/swift-socks-find.md

@@ -0,0 +1,5 @@
+---
+'next': patch
+---
+
+Sourcemap errors during prerender if `experimental.enablePrerenderSourceMaps` is enabled

packages/next/src/build/index.ts

@@ -758,6 +758,7 @@ export function createStaticWorker(
       progress?.clear()
     },
     debuggerPortOffset,
+    enableSourceMaps: config.experimental.enablePrerenderSourceMaps,
     // remove --max-old-space-size flag as it can cause memory issues.
     isolatedMemory: true,
     enableWorkerThreads: config.experimental.workerThreads,

packages/next/src/lib/worker.ts

@@ -43,6 +43,7 @@ export class Worker {
        * `-1` if not inspectable
        */
       debuggerPortOffset: number
+      enableSourceMaps?: boolean
       /**
        * True if `--max-old-space-size` should not be forwarded to the worker.
        */
@@ -57,6 +58,7 @@ export class Worker {
     }
   ) {
     let {
+      enableSourceMaps,
       timeout,
       onRestart,
       logger = console,
@@ -91,6 +93,10 @@ export class Worker {
       }
     }
 
+    if (enableSourceMaps) {
+      nodeOptions['enable-source-maps'] = true
+    }
+
     if (isolatedMemory) {
       delete nodeOptions['max-old-space-size']
       delete nodeOptions['max_old_space_size']

packages/next/src/server/config-schema.ts

@@ -464,6 +464,7 @@ export const configSchema: zod.ZodType<NextConfig> = z.lazy(() =>
         optimizeServerReact: z.boolean().optional(),
         clientTraceMetadata: z.array(z.string()).optional(),
         serverMinification: z.boolean().optional(),
+        enablePrerenderSourceMaps: z.boolean().optional(),
         serverSourceMaps: z.boolean().optional(),
         useWasmBinary: z.boolean().optional(),
         useLightningcss: z.boolean().optional(),

packages/next/src/server/config-shared.ts

@@ -559,6 +559,12 @@ export interface ExperimentalConfig {
    */
   serverMinification?: boolean
 
+  /**
+   * Enables source maps while generating static pages.
+   * Helps with errors during the prerender phase in `next build`.
+   */
+  enablePrerenderSourceMaps?: boolean
+
   /**
    * Enables source maps generation for the server production bundle.
    */
@@ -1309,6 +1315,7 @@ export const defaultConfig = {
     appNavFailHandling: false,
     prerenderEarlyExit: true,
     serverMinification: true,
+    enablePrerenderSourceMaps: false,
     serverSourceMaps: false,
     linkNoTouchStart: false,
     caseSensitiveRoutes: false,

test/e2e/app-dir/server-source-maps/fixtures/default/next.config.js

@@ -6,6 +6,7 @@ const nextConfig = {
     cpus: 1,
     ppr: true,
     dynamicIO: true,
+    enablePrerenderSourceMaps: true,
     serverSourceMaps: true,
   },
   serverExternalPackages: ['external-pkg'],

test/e2e/app-dir/server-source-maps/fixtures/edge/next.config.js

@@ -3,6 +3,8 @@
  */
 const nextConfig = {
   experimental: {
+    cpus: 1,
+    enablePrerenderSourceMaps: true,
     serverSourceMaps: true,
   },
 }

test/e2e/app-dir/server-source-maps/server-source-maps-edge.test.ts

@@ -42,7 +42,8 @@ describe('app-dir - server source maps edge runtime', () => {
           '\n}'
       )
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      // Edge runtime pages are not prerendered during `next build`.
+      // `next start` is not sourcemapped on purpose.
     }
   })
 
@@ -71,7 +72,8 @@ describe('app-dir - server source maps edge runtime', () => {
       )
       expect(cliOutput).toMatch(/digest: '\d+'/)
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      // Edge runtime pages are not prerendered during `next build`.
+      // `next start` is not sourcemapped on purpose.
     }
   })
 
@@ -99,7 +101,8 @@ describe('app-dir - server source maps edge runtime', () => {
       )
       expect(cliOutput).toMatch(/digest: '\d+'/)
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      // Edge runtime pages are not prerendered during `next build`.
+      // `next start` is not sourcemapped on purpose.
     }
   })
 })

test/e2e/app-dir/server-source-maps/server-source-maps.test.ts

@@ -25,10 +25,10 @@ describe('app-dir - server source maps', () => {
   if (skipped) return
 
   it('logged errors have a sourcemapped stack with a codeframe', async () => {
-    const outputIndex = next.cliOutput.length
-    await next.render('/rsc-error-log')
-
     if (isNextDev) {
+      const outputIndex = next.cliOutput.length
+      await next.render('/rsc-error-log')
+
       await retry(() => {
         expect(next.cliOutput.slice(outputIndex)).toContain(
           'Error: rsc-error-log'
@@ -48,15 +48,28 @@ describe('app-dir - server source maps', () => {
           '\n'
       )
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      if (isTurbopack) {
+        // TODO(veil): Sourcemap names
+        // TODO(veil): relative paths
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '(turbopack:///[project]/app/rsc-error-log/page.js:4:16)'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '' +
+            "\n> 4 |   const error = new Error('rsc-error-log')" +
+            '\n    |                ^'
+        )
+      } else {
+        // TODO(veil): line/column numbers are flaky in Webpack
+      }
     }
   })
 
   it('logged errors have a sourcemapped `cause`', async () => {
-    const outputIndex = next.cliOutput.length
-    await next.render('/rsc-error-log-cause')
-
     if (isNextDev) {
+      const outputIndex = next.cliOutput.length
+      await next.render('/rsc-error-log-cause')
+
       await retry(() => {
         expect(next.cliOutput.slice(outputIndex)).toContain(
           'Error: rsc-error-log-cause'
@@ -84,15 +97,36 @@ describe('app-dir - server source maps', () => {
           '\n'
       )
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      if (isTurbopack) {
+        // TODO(veil): Sourcemap names
+        // TODO(veil): relative paths
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '(turbopack:///[project]/app/rsc-error-log-cause/page.js:2:16)'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '(turbopack:///[project]/app/rsc-error-log-cause/page.js:7:16)'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '' +
+            "\n> 2 |   const error = new Error('rsc-error-log-cause', { cause })" +
+            '\n    |                ^'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '' +
+            "\n  >  7 |   const error = new Error('Boom')" +
+            '\n       |                ^'
+        )
+      } else {
+        // TODO(veil): line/column numbers are flaky in Webpack
+      }
     }
   })
 
   it('stack frames are ignore-listed in ssr', async () => {
-    const outputIndex = next.cliOutput.length
-    const browser = await next.browser('/ssr-error-log-ignore-listed')
-
     if (isNextDev) {
+      const outputIndex = next.cliOutput.length
+      const browser = await next.browser('/ssr-error-log-ignore-listed')
+
       await retry(() => {
         expect(next.cliOutput.slice(outputIndex)).toContain(
           'Error: ssr-error-log-ignore-listed'
@@ -189,7 +223,19 @@ describe('app-dir - server source maps', () => {
         `)
       }
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      if (isTurbopack) {
+        // TODO(veil): Sourcemapping line off
+        // TODO(veil): Sourcemap names
+        // TODO(veil): relative paths
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '(turbopack:///[project]/app/ssr-error-log-ignore-listed/page.js:24:2)'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '\n> 24 |   })\n     |  ^'
+        )
+      } else {
+        // TODO(veil): line/column numbers are flaky in Webpack
+      }
     }
   })
 
@@ -242,15 +288,28 @@ describe('app-dir - server source maps', () => {
               '\n'
       )
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      if (isTurbopack) {
+        // TODO(veil): Sourcemap names
+        // TODO(veil): relative paths
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          'at <unknown> (turbopack:///[project]/app/rsc-error-log-ignore-listed/page.js:8:16)'
+        )
+        expect(normalizeCliOutput(next.cliOutput)).toContain(
+          '' +
+            "\n>  8 |   const error = new Error('rsc-error-log-ignore-listed')" +
+            '\n     |                ^'
+        )
+      } else {
+        // TODO(veil): line/column numbers are flaky in Webpack
+      }
     }
   })
 
   it('thrown SSR errors', async () => {
-    const outputIndex = next.cliOutput.length
-    const browser = await next.browser('/ssr-throw')
-
     if (isNextDev) {
+      const outputIndex = next.cliOutput.length
+      const browser = await next.browser('/ssr-throw')
+
       await retry(() => {
         expect(next.cliOutput.slice(outputIndex)).toContain('Error: ssr-throw')
       })
@@ -287,7 +346,7 @@ describe('app-dir - server source maps', () => {
        }
       `)
     } else {
-      // TODO: Test `next build` with `--enable-source-maps`.
+      // SSR errors are not logged because React retries them during hydration.
     }
   })
 
@@ -356,7 +415,23 @@ describe('app-dir - server source maps', () => {
         ).toEqual(3)
       }
     } else {
-      // TODO: test `next start` with `--enable-source-maps`
+      if (isTurbopack) {
+        // Expect the invalid sourcemap warning only once per render.
+        expect(
+          normalizeCliOutput(next.cliOutput).split('Invalid source map.')
+            .length - 1
+        ).toEqual(
+          // >= 20
+          // behavior in Node.js 20+ is intended
+          process.versions.node.startsWith('18') ? 0 : 2
+        )
+      } else {
+        // Webpack is silent about invalid sourcemaps for next build.
+        expect(
+          normalizeCliOutput(next.cliOutput).split('Invalid source map.')
+            .length - 1
+        ).toEqual(0)
+      }
     }
   })
 })