[pull] canary from vercel:canary

lerna.json

@@ -15,5 +15,5 @@
       "registry": "https://registry.npmjs.org/"
     }
   },
-  "version": "16.2.0-canary.55"
+  "version": "16.2.0-canary.56"
 }

package.json

@@ -201,7 +201,7 @@
     "eslint-plugin-jsdoc": "48.0.4",
     "eslint-plugin-mdx": "3.1.5",
     "eslint-plugin-react": "7.37.0",
-    "eslint-plugin-react-hooks": "0.0.0-experimental-2ba30655-20260219",
+    "eslint-plugin-react-hooks": "0.0.0-experimental-ab18f33d-20260220",
     "event-stream": "4.0.1",
     "execa": "2.0.3",
     "expect": "29.7.0",
@@ -261,16 +261,16 @@
     "pretty-ms": "7.0.0",
     "random-seed": "0.3.0",
     "react": "19.0.0",
-    "react-builtin": "npm:react@19.3.0-canary-2ba30655-20260219",
+    "react-builtin": "npm:react@19.3.0-canary-ab18f33d-20260220",
     "react-dom": "19.0.0",
-    "react-dom-builtin": "npm:react-dom@19.3.0-canary-2ba30655-20260219",
-    "react-dom-experimental-builtin": "npm:react-dom@0.0.0-experimental-2ba30655-20260219",
-    "react-experimental-builtin": "npm:react@0.0.0-experimental-2ba30655-20260219",
-    "react-is-builtin": "npm:react-is@19.3.0-canary-2ba30655-20260219",
-    "react-server-dom-turbopack": "19.3.0-canary-2ba30655-20260219",
-    "react-server-dom-turbopack-experimental": "npm:react-server-dom-turbopack@0.0.0-experimental-2ba30655-20260219",
-    "react-server-dom-webpack": "19.3.0-canary-2ba30655-20260219",
-    "react-server-dom-webpack-experimental": "npm:react-server-dom-webpack@0.0.0-experimental-2ba30655-20260219",
+    "react-dom-builtin": "npm:react-dom@19.3.0-canary-ab18f33d-20260220",
+    "react-dom-experimental-builtin": "npm:react-dom@0.0.0-experimental-ab18f33d-20260220",
+    "react-experimental-builtin": "npm:react@0.0.0-experimental-ab18f33d-20260220",
+    "react-is-builtin": "npm:react-is@19.3.0-canary-ab18f33d-20260220",
+    "react-server-dom-turbopack": "19.3.0-canary-ab18f33d-20260220",
+    "react-server-dom-turbopack-experimental": "npm:react-server-dom-turbopack@0.0.0-experimental-ab18f33d-20260220",
+    "react-server-dom-webpack": "19.3.0-canary-ab18f33d-20260220",
+    "react-server-dom-webpack-experimental": "npm:react-server-dom-webpack@0.0.0-experimental-ab18f33d-20260220",
     "react-ssr-prepass": "1.0.8",
     "react-virtualized": "9.22.3",
     "relay-compiler": "13.0.2",
@@ -280,8 +280,8 @@
     "resolve-from": "5.0.0",
     "sass": "1.54.0",
     "satori": "0.15.2",
-    "scheduler-builtin": "npm:scheduler@0.28.0-canary-2ba30655-20260219",
-    "scheduler-experimental-builtin": "npm:scheduler@0.0.0-experimental-2ba30655-20260219",
+    "scheduler-builtin": "npm:scheduler@0.28.0-canary-ab18f33d-20260220",
+    "scheduler-experimental-builtin": "npm:scheduler@0.0.0-experimental-ab18f33d-20260220",
     "seedrandom": "3.0.5",
     "semver": "7.3.7",
     "serve-handler": "6.1.6",
@@ -326,10 +326,10 @@
       "@types/react-dom": "19.2.3",
       "@types/retry": "0.12.0",
       "jest-snapshot": "30.0.0-alpha.6",
-      "react": "19.3.0-canary-2ba30655-20260219",
-      "react-dom": "19.3.0-canary-2ba30655-20260219",
-      "react-is": "19.3.0-canary-2ba30655-20260219",
-      "scheduler": "0.28.0-canary-2ba30655-20260219"
+      "react": "19.3.0-canary-ab18f33d-20260220",
+      "react-dom": "19.3.0-canary-ab18f33d-20260220",
+      "react-is": "19.3.0-canary-ab18f33d-20260220",
+      "scheduler": "0.28.0-canary-ab18f33d-20260220"
     },
     "packageExtensions": {
       "eslint-plugin-react-hooks@0.0.0-experimental-6de32a5a-20250822": {

packages/create-next-app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "create-next-app",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "keywords": [
     "react",
     "next",

packages/eslint-config-next/package.json

@@ -1,6 +1,6 @@
 {
   "name": "eslint-config-next",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "ESLint configuration used by Next.js.",
   "license": "MIT",
   "repository": {
@@ -12,7 +12,7 @@
     "dist"
   ],
   "dependencies": {
-    "@next/eslint-plugin-next": "16.2.0-canary.55",
+    "@next/eslint-plugin-next": "16.2.0-canary.56",
     "eslint-import-resolver-node": "^0.3.6",
     "eslint-import-resolver-typescript": "^3.5.2",
     "eslint-plugin-import": "^2.32.0",

packages/eslint-plugin-internal/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@next/eslint-plugin-internal",
   "private": true,
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "ESLint plugin for working on Next.js.",
   "exports": {
     ".": "./src/eslint-plugin-internal.js"

packages/eslint-plugin-next/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/eslint-plugin-next",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "ESLint plugin for Next.js.",
   "main": "dist/index.js",
   "types": "dist/index.d.ts",

packages/font/package.json

@@ -1,7 +1,7 @@
 {
   "name": "@next/font",
   "private": true,
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "repository": {
     "url": "vercel/next.js",
     "directory": "packages/font"

packages/next-bundle-analyzer/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/bundle-analyzer",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "main": "index.js",
   "types": "index.d.ts",
   "license": "MIT",

packages/next-codemod/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/codemod",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "license": "MIT",
   "repository": {
     "type": "git",

packages/next-env/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/env",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "keywords": [
     "react",
     "next",

packages/next-mdx/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/mdx",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "main": "index.js",
   "license": "MIT",
   "repository": {

packages/next-plugin-storybook/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/plugin-storybook",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "repository": {
     "url": "vercel/next.js",
     "directory": "packages/next-plugin-storybook"

packages/next-polyfill-module/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/polyfill-module",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "A standard library polyfill for ES Modules supporting browsers (Edge 16+, Firefox 60+, Chrome 61+, Safari 10.1+)",
   "main": "dist/polyfill-module.js",
   "license": "MIT",

packages/next-polyfill-nomodule/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/polyfill-nomodule",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "A polyfill for non-dead, nomodule browsers.",
   "main": "dist/polyfill-nomodule.js",
   "license": "MIT",

packages/next-routing/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/routing",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "keywords": [
     "react",
     "next",

packages/next-rspack/package.json

@@ -1,6 +1,6 @@
 {
   "name": "next-rspack",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "repository": {
     "url": "vercel/next.js",
     "directory": "packages/next-rspack"

packages/next-swc/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@next/swc",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "private": true,
   "files": [
     "native/"

packages/next/package.json

@@ -1,6 +1,6 @@
 {
   "name": "next",
-  "version": "16.2.0-canary.55",
+  "version": "16.2.0-canary.56",
   "description": "The React Framework",
   "main": "./dist/server/next.js",
   "license": "MIT",
@@ -97,7 +97,7 @@
     ]
   },
   "dependencies": {
-    "@next/env": "16.2.0-canary.55",
+    "@next/env": "16.2.0-canary.56",
     "@swc/helpers": "0.5.15",
     "baseline-browser-mapping": "^2.9.19",
     "caniuse-lite": "^1.0.30001579",
@@ -162,11 +162,11 @@
     "@modelcontextprotocol/sdk": "1.18.1",
     "@mswjs/interceptors": "0.23.0",
     "@napi-rs/triples": "1.2.0",
-    "@next/font": "16.2.0-canary.55",
-    "@next/polyfill-module": "16.2.0-canary.55",
-    "@next/polyfill-nomodule": "16.2.0-canary.55",
-    "@next/react-refresh-utils": "16.2.0-canary.55",
-    "@next/swc": "16.2.0-canary.55",
+    "@next/font": "16.2.0-canary.56",
+    "@next/polyfill-module": "16.2.0-canary.56",
+    "@next/polyfill-nomodule": "16.2.0-canary.56",
+    "@next/react-refresh-utils": "16.2.0-canary.56",
+    "@next/swc": "16.2.0-canary.56",
     "@opentelemetry/api": "1.6.0",
     "@playwright/test": "1.51.1",
     "@rspack/core": "1.6.7",

packages/next/src/client/components/segment-cache/cache.ts

@@ -14,7 +14,6 @@ import {
 import {
   NEXT_DID_POSTPONE_HEADER,
   NEXT_INSTANT_PREFETCH_HEADER,
-  NEXT_IS_PRERENDER_HEADER,
   NEXT_ROUTER_PREFETCH_HEADER,
   NEXT_ROUTER_SEGMENT_PREFETCH_HEADER,
   NEXT_ROUTER_STALE_TIME_HEADER,
@@ -2015,14 +2014,9 @@ export async function fetchSegmentPrefetchesUsingDynamicRequest(
 
     let isResponsePartial = false
     let responseBody = response.body
-
-    // For dynamic runtime prefetches, strip the leading isPartial byte before
-    // passing the stream to Flight. Static responses (served from cache) don't
-    // have the byte. We detect them via NEXT_IS_PRERENDER_HEADER.
-    if (
-      fetchStrategy === FetchStrategy.PPRRuntime &&
-      !response.headers.get(NEXT_IS_PRERENDER_HEADER)
-    ) {
+    // For runtime prefetches, strip the leading isPartial byte before passing
+    // the stream to Flight.
+    if (fetchStrategy === FetchStrategy.PPRRuntime) {
       const stripped = await stripIsPartialByte(responseBody)
       isResponsePartial = stripped.isPartial
       responseBody = stripped.stream
@@ -2645,8 +2639,17 @@ async function getStaleAt(
 }
 
 /**
- * Strips the leading isPartial byte from a runtime prefetch response stream.
- * Returns the remaining stream and whether the response is partial.
+ * Checks for and strips the leading isPartial byte from a runtime prefetch
+ * response stream. If the first byte is a recognized marker ('~' for partial,
+ * '#' for complete), it is stripped and isPartial is set accordingly. If the
+ * first byte is not a recognized marker (e.g. for static responses that were
+ * not generated by the runtime prefetch codepath), the stream is returned
+ * intact with isPartial set to false.
+ *
+ * This is safe because the marker bytes (0x7e '~', 0x23 '#') cannot appear as
+ * the first byte of a valid RSC Flight response. Flight rows start with either
+ * a row ID (a hex character) or ':' (0x3a) for hint and debug chunks. Neither
+ * overlaps with the marker bytes.
  */
 async function stripIsPartialByte(
   stream: ReadableStream<Uint8Array>
@@ -2659,8 +2662,18 @@ async function stripIsPartialByte(
       isPartial: false,
     }
   }
-  const isPartial = value[0] === 0x7e // ASCII '~'
-  const remainder = value.byteLength > 1 ? value.subarray(1) : null
+
+  const firstByte = value[0]
+  // '~' (0x7e) = partial, '#' (0x23) = complete
+  const hasMarker = firstByte === 0x7e || firstByte === 0x23
+  const isPartial = firstByte === 0x7e
+
+  const remainder = hasMarker
+    ? value.byteLength > 1
+      ? value.subarray(1)
+      : null
+    : value
+
   return {
     isPartial,
     stream: new ReadableStream<Uint8Array>({