Enable Node streams by default

.github/workflows/build_and_test.yml

@@ -1013,134 +1013,6 @@ jobs:
       stepName: 'test-cache-components-prod-${{ matrix.group }}'
     secrets: inherit
 
-  test-node-streams-cache-components-dev:
-    name: test node streams cache components dev
-    needs:
-      [
-        'optimize-ci',
-        'changes',
-        'build-native',
-        'build-next',
-        'fetch-test-timings',
-      ]
-    if: ${{ needs.optimize-ci.outputs.skip == 'false' && needs.changes.outputs.docs-only == 'false' }}
-
-    strategy:
-      fail-fast: false
-      matrix:
-        group: [1/6, 2/6, 3/6, 4/6, 5/6, 6/6]
-    uses: ./.github/workflows/build_reusable.yml
-    with:
-      afterBuild: |
-        export __NEXT_USE_NODE_STREAMS=true
-        export __NEXT_CACHE_COMPONENTS=true
-        export __NEXT_EXPERIMENTAL_CACHED_NAVIGATIONS=true
-        export __NEXT_EXPERIMENTAL_APP_NEW_SCROLL_HANDLER=true
-        export NEXT_EXTERNAL_TESTS_FILTERS="test/cache-components-tests-manifest.json"
-        export NEXT_TEST_MODE=dev
-        export IS_TURBOPACK_TEST=1
-        export TURBOPACK_DEV=1
-
-        node run-tests.js \
-          --timings \
-          --require-timings \
-          -g ${{ matrix.group }} \
-          --type development
-      testTimingsArtifact: 'test-timings'
-      stepName: 'test-node-streams-cache-components-dev-${{ matrix.group }}'
-    secrets: inherit
-
-  test-node-streams-cache-components-prod:
-    name: test node streams cache components prod
-    needs:
-      [
-        'optimize-ci',
-        'changes',
-        'build-native',
-        'build-next',
-        'fetch-test-timings',
-      ]
-    if: ${{ needs.optimize-ci.outputs.skip == 'false' && needs.changes.outputs.docs-only == 'false' }}
-
-    strategy:
-      fail-fast: false
-      matrix:
-        group: [1/7, 2/7, 3/7, 4/7, 5/7, 6/7, 7/7]
-    uses: ./.github/workflows/build_reusable.yml
-    with:
-      afterBuild: |
-        export __NEXT_USE_NODE_STREAMS=true
-        export __NEXT_CACHE_COMPONENTS=true
-        export __NEXT_EXPERIMENTAL_CACHED_NAVIGATIONS=true
-        export __NEXT_EXPERIMENTAL_APP_NEW_SCROLL_HANDLER=true
-        export NEXT_EXTERNAL_TESTS_FILTERS="test/cache-components-tests-manifest.json"
-        export NEXT_TEST_MODE=start
-        export IS_TURBOPACK_TEST=1
-        export TURBOPACK_BUILD=1
-
-        node run-tests.js \
-          --timings \
-          --require-timings \
-          -g ${{ matrix.group }} \
-          --type production
-      testTimingsArtifact: 'test-timings'
-      stepName: 'test-node-streams-cache-components-prod-${{ matrix.group }}'
-    secrets: inherit
-
-  test-node-streams-dev:
-    name: test node streams dev
-    needs: ['optimize-ci', 'changes', 'build-native', 'build-next']
-    if: ${{ needs.optimize-ci.outputs.skip == 'false' && needs.changes.outputs.docs-only == 'false' }}
-
-    strategy:
-      fail-fast: false
-      matrix:
-        group: [1/6, 2/6, 3/6, 4/6, 5/6, 6/6]
-    uses: ./.github/workflows/build_reusable.yml
-    with:
-      afterBuild: |
-        export __NEXT_USE_NODE_STREAMS=true
-        export NEXT_EXTERNAL_TESTS_FILTERS="test/use-node-streams-tests-manifest.json"
-        export NEXT_TEST_MODE=dev
-        export IS_TURBOPACK_TEST=1
-        export TURBOPACK_DEV=1
-        export __NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES=true
-        export RUST_BACKTRACE=1
-
-        node run-tests.js \
-          --timings \
-          -g ${{ matrix.group }} \
-          --type development
-      stepName: 'test-node-streams-dev-${{ matrix.group }}'
-    secrets: inherit
-
-  test-node-streams-prod:
-    name: test node streams prod
-    needs: ['optimize-ci', 'changes', 'build-native', 'build-next']
-    if: ${{ needs.optimize-ci.outputs.skip == 'false' && needs.changes.outputs.docs-only == 'false' }}
-
-    strategy:
-      fail-fast: false
-      matrix:
-        group: [1/7, 2/7, 3/7, 4/7, 5/7, 6/7, 7/7]
-    uses: ./.github/workflows/build_reusable.yml
-    with:
-      afterBuild: |
-        export __NEXT_USE_NODE_STREAMS=true
-        export NEXT_EXTERNAL_TESTS_FILTERS="test/use-node-streams-tests-manifest.json"
-        export NEXT_TEST_MODE=start
-        export IS_TURBOPACK_TEST=1
-        export TURBOPACK_BUILD=1
-        export __NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES=true
-        export RUST_BACKTRACE=1
-
-        node run-tests.js \
-          --timings \
-          -g ${{ matrix.group }} \
-          --type production
-      stepName: 'test-node-streams-prod-${{ matrix.group }}'
-    secrets: inherit
-
   tests-pass:
     needs:
       [
@@ -1157,10 +1029,6 @@ jobs:
         'test-firefox-safari',
         'test-cache-components-dev',
         'test-cache-components-prod',
-        'test-node-streams-cache-components-dev',
-        'test-node-streams-cache-components-prod',
-        'test-node-streams-dev',
-        'test-node-streams-prod',
         'test-cargo-unit',
         'rust-check',
         'rustdoc-check',

packages/next-env/index.ts

@@ -18,7 +18,17 @@ let cachedLoadedEnvFiles: LoadedEnvFiles = []
 let previousLoadedEnvFiles: LoadedEnvFiles = []
 
 export function updateInitialEnv(newEnv: Env) {
-  Object.assign(initialEnv || {}, newEnv)
+  if (!initialEnv) {
+    return
+  }
+
+  for (const [key, value] of Object.entries(newEnv)) {
+    if (value === undefined) {
+      delete initialEnv[key]
+    } else {
+      initialEnv[key] = value
+    }
+  }
 }
 
 type Log = {

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

@@ -2040,6 +2040,7 @@ export const defaultConfig = Object.freeze({
     gestureTransition: false,
     inlineCss: false,
     useCache: undefined,
+    useNodeStreams: true,
     slowModuleDetection: undefined,
     globalNotFound: false,
     browserDebugInfoInTerminal: 'warn',

packages/next/src/server/config.ts

@@ -1620,9 +1620,28 @@ function finalizeConfig(config: NextConfigComplete): NextConfigComplete {
     validationLevel:
       config.experimental.instantInsights?.validationLevel ?? 'manual-warning',
   }
+  syncUseNodeStreamsEnv(config)
   return config
 }
 
+function syncUseNodeStreamsEnv(config: NextConfig): void {
+  // This must use resolved config: user configs are inspected before defaults
+  // are merged, while runtime bundles must select the default implementation.
+  const useNodeStreams = config.experimental?.useNodeStreams
+    ? 'true'
+    : undefined
+
+  if (useNodeStreams) {
+    process.env.__NEXT_USE_NODE_STREAMS = useNodeStreams
+  } else {
+    delete process.env.__NEXT_USE_NODE_STREAMS
+  }
+
+  // Dev env reloads restore process.env from this snapshot. Preserve the
+  // resolved runtime selection so a reload cannot mix stream implementations.
+  updateInitialEnv({ __NEXT_USE_NODE_STREAMS: useNodeStreams })
+}
+
 async function applyModifyConfig(
   config: NextConfigComplete,
   phase: PHASE_TYPE,
@@ -1750,6 +1769,7 @@ export default async function loadConfig(
       return cachedResult.rawConfig
     }
 
+    syncUseNodeStreamsEnv(cachedResult.config)
     return cachedResult.config
   } else {
     // Reset next.config errors before loading config
@@ -1777,6 +1797,8 @@ export default async function loadConfig(
       process.env.__NEXT_PRIVATE_STANDALONE_CONFIG
     )
 
+    syncUseNodeStreamsEnv(standaloneConfig)
+
     // Cache the standalone config
     configCache.set(cacheKey, {
       config: standaloneConfig,
@@ -2229,16 +2251,6 @@ function enforceExperimentalFeatures(
     config.experimental.useNodeStreams = true
   }
 
-  // Keep runtime bundle selection env in sync with the resolved config.
-  // Explicit user config (e.g. useNodeStreams: false) should win over an
-  // inherited shell env var to avoid selecting nodestream runtime bundles
-  // while define-env compiled user bundles with node streams disabled.
-  if (config.experimental.useNodeStreams) {
-    process.env.__NEXT_USE_NODE_STREAMS = 'true'
-  } else {
-    delete process.env.__NEXT_USE_NODE_STREAMS
-  }
-
   // TODO: Remove this once strictRouteTypes is the default.
   if (
     process.env.__NEXT_EXPERIMENTAL_STRICT_ROUTE_TYPES === 'true' &&

test/unit/preserve-process-env.test.ts

@@ -1,9 +1,29 @@
-import { loadEnvConfig } from '../../packages/next-env/'
+import {
+  loadEnvConfig,
+  resetEnv,
+  updateInitialEnv,
+} from '../../packages/next-env/'
 
 describe('preserve process env', () => {
   it('should not reassign `process.env`', () => {
     const originalProcessEnv = process.env
     loadEnvConfig('.')
     expect(Object.is(originalProcessEnv, process.env)).toBeTrue()
   })
+
+  it('should remove values unset in the initial env snapshot', () => {
+    const key = '__NEXT_TEST_UNSET_INITIAL_ENV'
+
+    try {
+      loadEnvConfig('.')
+      process.env[key] = 'changed'
+      updateInitialEnv({ [key]: undefined })
+
+      resetEnv()
+
+      expect(process.env[key]).toBeUndefined()
+    } finally {
+      delete process.env[key]
+    }
+  })
 })