From 215972684964c6b78d5225f102a8ed9529b3bed5 Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Wed, 15 Oct 2025 04:29:13 +0200
Subject: [PATCH 01/11] Improve Proxy invalid export error message

---
 Cargo.lock                                    |  1 +
 crates/next-core/Cargo.toml                   |  1 +
 crates/next-core/src/middleware.rs            | 77 +++++++++++++++----
 packages/next/errors.json                     |  3 +-
 .../build/analysis/get-page-static-info.ts    | 18 ++++-
 .../next/src/build/templates/middleware.ts    | 18 ++++-
 6 files changed, 98 insertions(+), 20 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index cca56b629f964..efa500f3d8c07 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4322,6 +4322,7 @@ dependencies = [
  "next-custom-transforms",
  "next-taskless",
  "once_cell",
+ "pathdiff",
  "percent-encoding",
  "qstring",
  "react_remove_properties",
diff --git a/crates/next-core/Cargo.toml b/crates/next-core/Cargo.toml
index 90f77cbcd556f..3b480e562a23d 100644
--- a/crates/next-core/Cargo.toml
+++ b/crates/next-core/Cargo.toml
@@ -15,6 +15,7 @@ workspace = true
 anyhow = { workspace = true }
 async-trait = { workspace = true }
 base64 = "0.21.0"
+pathdiff = { workspace = true }
 either = { workspace = true, features = ["serde"] }
 once_cell = { workspace = true }
 qstring = { workspace = true }
diff --git a/crates/next-core/src/middleware.rs b/crates/next-core/src/middleware.rs
index 49c4a44c73eca..cb0cc43e6d0a7 100644
--- a/crates/next-core/src/middleware.rs
+++ b/crates/next-core/src/middleware.rs
@@ -1,4 +1,7 @@
+use std::env;
+
 use anyhow::Result;
+use pathdiff::diff_paths;
 use turbo_rcstr::{RcStr, rcstr};
 use turbo_tasks::{ResolvedVc, Vc, fxindexmap};
 use turbo_tasks_fs::FileSystemPath;
@@ -122,6 +125,30 @@ struct MiddlewareMissingExportIssue {
     file_path: FileSystemPath,
 }
 
+impl MiddlewareMissingExportIssue {
+    fn get_relative_path(&self) -> String {
+        // Get relative path from current working directory (like process.cwd() in JavaScript)
+        let cwd = env::current_dir().ok();
+        let file_path_str = self.file_path.path.as_str();
+        let relative_path = if let Some(cwd) = cwd {
+            diff_paths(file_path_str, cwd)
+                .and_then(|p| p.to_str().map(|s| s.to_string()))
+                .unwrap_or_else(|| self.file_path.file_name().to_string())
+        } else {
+            self.file_path.file_name().to_string()
+        };
+        format!("./{}", relative_path)
+    }
+
+    fn get_type_description(&self) -> &str {
+        if self.file_type.as_str() == "Proxy" {
+            "proxy (previously called middleware)"
+        } else {
+            "middleware"
+        }
+    }
+}
+
 #[turbo_tasks::value_impl]
 impl Issue for MiddlewareMissingExportIssue {
     #[turbo_tasks::function]
@@ -139,23 +166,43 @@ impl Issue for MiddlewareMissingExportIssue {
     }
 
     #[turbo_tasks::function]
-    fn title(&self) -> Vc<StyledString> {
-        let file_name = self.file_path.file_name();
-
-        StyledString::Line(vec![
-            StyledString::Text(rcstr!("The ")),
-            StyledString::Code(self.file_type.clone()),
-            StyledString::Text(rcstr!(" file \"")),
-            StyledString::Code(format!("./{}", file_name).into()),
-            StyledString::Text(rcstr!("\" must export a function named ")),
-            StyledString::Code(format!("`{}`", self.function_name).into()),
-            StyledString::Text(rcstr!(" or a default function.")),
-        ])
-        .cell()
+    async fn title(&self) -> Result<Vc<StyledString>> {
+        let relative_path_str = self.get_relative_path();
+
+        // Only the first line goes in title to avoid formatIssue indentation
+        let title_text = format!(
+            "The file \"{}\" must export a function, either as a default export or as a named \
+             \"{}\" export.",
+            relative_path_str, self.function_name
+        );
+
+        Ok(StyledString::Text(title_text.into()).cell())
     }
 
     #[turbo_tasks::function]
-    fn description(&self) -> Vc<OptionStyledString> {
-        Vc::cell(None)
+    async fn description(&self) -> Result<Vc<OptionStyledString>> {
+        let relative_path_str = self.get_relative_path();
+        let type_description = self.get_type_description();
+
+        // Rest of the message goes in description to avoid formatIssue indentation
+        let description_text = format!(
+            "This function is what Next.js runs for every request handled by this {}.\n\n\
+             Why this happens:\n\
+             - The file exists but doesn't export a function.\n\
+             - The export is not a function (e.g., an object or constant).\n\
+             - There's a syntax error preventing the export from being recognized.\n\n\
+             To fix it:\n\
+             - Check your \"{}\" file.\n\
+             - Ensure it has either a default or \"{}\" function export.\n\
+             - Restart the dev server if the error persists.\n\n\
+             Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+            type_description,
+            relative_path_str,
+            self.function_name
+        );
+
+        Ok(Vc::cell(Some(
+            StyledString::Text(description_text.into()).resolved_cell(),
+        )))
     }
 }
diff --git a/packages/next/errors.json b/packages/next/errors.json
index 7563516b715a3..9b75d28575d13 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -900,5 +900,6 @@
   "899": "Both \"%s\" and \"%s\" files are detected. Please use \"%s\" instead. Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "900": "Both %s file \"./%s\" and %s file \"./%s\" are detected. Please use \"./%s\" only. Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "901": "Invalid \"cacheHandlers\" provided, expected an object e.g. { default: '/my-handler.js' }, received %s",
-  "902": "Invalid handler fields configured for \"cacheHandlers\":\\n%s"
+  "902": "Invalid handler fields configured for \"cacheHandlers\":\\n%s",
+  "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }
diff --git a/packages/next/src/build/analysis/get-page-static-info.ts b/packages/next/src/build/analysis/get-page-static-info.ts
index bc01e7e856374..cbbd65a77874b 100644
--- a/packages/next/src/build/analysis/get-page-static-info.ts
+++ b/packages/next/src/build/analysis/get-page-static-info.ts
@@ -2,7 +2,7 @@ import type { NextConfig } from '../../server/config-shared'
 import type { RouteHas } from '../../lib/load-custom-routes'
 
 import { promises as fs } from 'fs'
-import { basename } from 'path'
+import { relative } from 'path'
 import { LRUCache } from '../../server/lib/lru-cache'
 import {
   extractExportedConstValue,
@@ -329,7 +329,7 @@ function validateMiddlewareProxyExports({
     return
   }
 
-  const fileName = isProxy ? 'proxy' : 'middleware'
+  const fileName = isProxy ? PROXY_FILENAME : MIDDLEWARE_FILENAME
 
   // Parse AST to get export info (since checkExports doesn't return middleware/proxy info)
   let hasDefaultExport = false
@@ -396,9 +396,21 @@ function validateMiddlewareProxyExports({
     (isMiddleware && hasMiddlewareExport) ||
     (isProxy && hasProxyExport)
 
+  const relativeFilePath = `./${relative(process.cwd(), pageFilePath)}`
+
   if (!hasValidExport) {
     throw new Error(
-      `The ${fileName === 'proxy' ? 'Proxy' : 'Middleware'} file "./${basename(pageFilePath)}" must export a function named \`${fileName}\` or a default function.`
+      `The file "${relativeFilePath}" must export a function, either as a default export or as a named "${fileName}" export.\n` +
+        `This function is what Next.js runs for every request handled by this ${fileName === 'proxy' ? 'proxy (previously called middleware)' : 'middleware'}.\n\n` +
+        `Why this happens:\n` +
+        `- The file exists but doesn't export a function.\n` +
+        `- The export is not a function (e.g., an object or constant).\n` +
+        `- There's a syntax error preventing the export from being recognized.\n\n` +
+        `To fix it:\n` +
+        `- Check your "${relativeFilePath}" file.\n` +
+        `- Ensure it has either a default or "${fileName}" function export.\n` +
+        `- Restart the dev server if the error persists.\n\n` +
+        `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
     )
   }
 }
diff --git a/packages/next/src/build/templates/middleware.ts b/packages/next/src/build/templates/middleware.ts
index 7526961fe65bc..f9024b3e062c5 100644
--- a/packages/next/src/build/templates/middleware.ts
+++ b/packages/next/src/build/templates/middleware.ts
@@ -19,8 +19,24 @@ const isProxy = page === '/proxy' || page === '/src/proxy'
 const handler = (isProxy ? mod.proxy : mod.middleware) || mod.default
 
 if (typeof handler !== 'function') {
+  const fileName = isProxy ? 'proxy' : 'middleware'
+  // Webpack starts the path with "." as relative, but Turbopack does not.
+  const resolvedRelativeFilePath = relativeFilePath.startsWith('.')
+    ? relativeFilePath
+    : `./${relativeFilePath}`
+
   throw new Error(
-    `The ${isProxy ? 'Proxy' : 'Middleware'} file "${relativeFilePath.startsWith('.') ? relativeFilePath : `./${relativeFilePath}`}" must export a function named \`${isProxy ? 'proxy' : 'middleware'}\` or a default function.`
+    `The file "${resolvedRelativeFilePath}" must export a function, either as a default export or as a named "${fileName}" export.\n` +
+      `This function is what Next.js runs for every request handled by this ${fileName === 'proxy' ? 'proxy (previously called middleware)' : 'middleware'}.\n\n` +
+      `Why this happens:\n` +
+      `- The file exists but doesn't export a function.\n` +
+      `- The export is not a function (e.g., an object or constant).\n` +
+      `- There's a syntax error preventing the export from being recognized.\n\n` +
+      `To fix it:\n` +
+      `- Check your "${resolvedRelativeFilePath}" file.\n` +
+      `- Ensure it has either a default or "${fileName}" function export.\n` +
+      `- Restart the dev server if the error persists.\n\n` +
+      `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
   )
 }
 

From faca60a9a4174c5abf2501bdf0f7bc5c7664f92f Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Fri, 17 Oct 2025 21:12:39 +0200
Subject: [PATCH 02/11] Update test

---
 .../proxy-missing-export.test.ts                 | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index 61813a45ee11c..559666027cb53 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -2,8 +2,20 @@ import { nextTestSetup } from 'e2e-utils'
 import { join } from 'node:path'
 import { writeFile } from 'node:fs/promises'
 
-const errorMessage =
-  'The Proxy file "./proxy.ts" must export a function named `proxy` or a default function.'
+const errorMessage = `The file "./proxy.ts" must export a function, either as a default export or as a named "proxy" export.
+This function is what Next.js runs for every request handled by this proxy (previously called middleware).
+
+Why this happens:
+- The file exists but doesn't export a function.
+- The export is not a function (e.g., an object or constant).
+- There's a syntax error preventing the export from being recognized.
+
+To fix it:
+- Check your "./proxy.ts" file.
+- Ensure it has either a default or "proxy" function export.
+- Restart the dev server if the error persists.
+
+Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
 
 describe('proxy-missing-export', () => {
   const { next, isNextDev, skipped } = nextTestSetup({

From b5f67fa85f37562b72aea7376766d07c1dad50f1 Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Fri, 17 Oct 2025 21:56:52 +0200
Subject: [PATCH 03/11] Add additional bullet for proxy

Co-authored-by: Joseph <sephxd1234@gmail.com>
---
 crates/next-core/src/middleware.rs                       | 9 +++++++++
 packages/next/src/build/analysis/get-page-static-info.ts | 3 +++
 packages/next/src/build/templates/middleware.ts          | 3 +++
 .../proxy-missing-export/proxy-missing-export.test.ts    | 1 +
 4 files changed, 16 insertions(+)

diff --git a/crates/next-core/src/middleware.rs b/crates/next-core/src/middleware.rs
index cb0cc43e6d0a7..dc1128dd74125 100644
--- a/crates/next-core/src/middleware.rs
+++ b/crates/next-core/src/middleware.rs
@@ -184,10 +184,18 @@ impl Issue for MiddlewareMissingExportIssue {
         let relative_path_str = self.get_relative_path();
         let type_description = self.get_type_description();
 
+        let migration_bullet = if self.file_type.as_str() == "Proxy" {
+            "- You are migrating from `middleware` to `proxy`, but haven't updated the exported \
+             function.\n"
+        } else {
+            ""
+        };
+
         // Rest of the message goes in description to avoid formatIssue indentation
         let description_text = format!(
             "This function is what Next.js runs for every request handled by this {}.\n\n\
              Why this happens:\n\
+             {}\
              - The file exists but doesn't export a function.\n\
              - The export is not a function (e.g., an object or constant).\n\
              - There's a syntax error preventing the export from being recognized.\n\n\
@@ -197,6 +205,7 @@ impl Issue for MiddlewareMissingExportIssue {
              - Restart the dev server if the error persists.\n\n\
              Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
             type_description,
+            migration_bullet,
             relative_path_str,
             self.function_name
         );
diff --git a/packages/next/src/build/analysis/get-page-static-info.ts b/packages/next/src/build/analysis/get-page-static-info.ts
index cbbd65a77874b..30db844f6474a 100644
--- a/packages/next/src/build/analysis/get-page-static-info.ts
+++ b/packages/next/src/build/analysis/get-page-static-info.ts
@@ -403,6 +403,9 @@ function validateMiddlewareProxyExports({
       `The file "${relativeFilePath}" must export a function, either as a default export or as a named "${fileName}" export.\n` +
         `This function is what Next.js runs for every request handled by this ${fileName === 'proxy' ? 'proxy (previously called middleware)' : 'middleware'}.\n\n` +
         `Why this happens:\n` +
+        (isProxy
+          ? "- You are migrating from `middleware` to `proxy`, but haven't updated the exported function.\n"
+          : '') +
         `- The file exists but doesn't export a function.\n` +
         `- The export is not a function (e.g., an object or constant).\n` +
         `- There's a syntax error preventing the export from being recognized.\n\n` +
diff --git a/packages/next/src/build/templates/middleware.ts b/packages/next/src/build/templates/middleware.ts
index f9024b3e062c5..d30f7d8098867 100644
--- a/packages/next/src/build/templates/middleware.ts
+++ b/packages/next/src/build/templates/middleware.ts
@@ -29,6 +29,9 @@ if (typeof handler !== 'function') {
     `The file "${resolvedRelativeFilePath}" must export a function, either as a default export or as a named "${fileName}" export.\n` +
       `This function is what Next.js runs for every request handled by this ${fileName === 'proxy' ? 'proxy (previously called middleware)' : 'middleware'}.\n\n` +
       `Why this happens:\n` +
+      (isProxy
+        ? "- You are migrating from `middleware` to `proxy`, but haven't updated the exported function.\n"
+        : '') +
       `- The file exists but doesn't export a function.\n` +
       `- The export is not a function (e.g., an object or constant).\n` +
       `- There's a syntax error preventing the export from being recognized.\n\n` +
diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index 559666027cb53..4b9ad4debf45b 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -6,6 +6,7 @@ const errorMessage = `The file "./proxy.ts" must export a function, either as a
 This function is what Next.js runs for every request handled by this proxy (previously called middleware).
 
 Why this happens:
+- You are migrating from \`middleware\` to \`proxy\`, but haven't updated the exported function.
 - The file exists but doesn't export a function.
 - The export is not a function (e.g., an object or constant).
 - There's a syntax error preventing the export from being recognized.

From 4404f3f3504a3f2aca80e60bdc5d88346cd48b3f Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Fri, 17 Oct 2025 21:58:13 +0200
Subject: [PATCH 04/11] Update errors.json

---
 packages/next/errors.json | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/packages/next/errors.json b/packages/next/errors.json
index 9b75d28575d13..740f4cc90e833 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -901,5 +901,6 @@
   "900": "Both %s file \"./%s\" and %s file \"./%s\" are detected. Please use \"./%s\" only. Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "901": "Invalid \"cacheHandlers\" provided, expected an object e.g. { default: '/my-handler.js' }, received %s",
   "902": "Invalid handler fields configured for \"cacheHandlers\":\\n%s",
-  "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
+  "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+  "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }

From dbdcfc5814defa889f23024940dc28327ab8df2b Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Mon, 20 Oct 2025 19:13:36 -0700
Subject: [PATCH 05/11] Remove "Restart the dev server if the error persists."

---
 crates/next-core/src/middleware.rs                            | 3 +--
 packages/next/errors.json                                     | 4 +++-
 packages/next/src/build/analysis/get-page-static-info.ts      | 3 +--
 packages/next/src/build/templates/middleware.ts               | 3 +--
 .../app-dir/proxy-missing-export/proxy-missing-export.test.ts | 1 -
 5 files changed, 6 insertions(+), 8 deletions(-)

diff --git a/crates/next-core/src/middleware.rs b/crates/next-core/src/middleware.rs
index dc1128dd74125..fe17fb9f699ab 100644
--- a/crates/next-core/src/middleware.rs
+++ b/crates/next-core/src/middleware.rs
@@ -201,8 +201,7 @@ impl Issue for MiddlewareMissingExportIssue {
              - There's a syntax error preventing the export from being recognized.\n\n\
              To fix it:\n\
              - Check your \"{}\" file.\n\
-             - Ensure it has either a default or \"{}\" function export.\n\
-             - Restart the dev server if the error persists.\n\n\
+             - Ensure it has either a default or \"{}\" function export.\n\n\
              Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
             type_description,
             migration_bullet,
diff --git a/packages/next/errors.json b/packages/next/errors.json
index 740f4cc90e833..86b9beb0920cd 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -902,5 +902,7 @@
   "901": "Invalid \"cacheHandlers\" provided, expected an object e.g. { default: '/my-handler.js' }, received %s",
   "902": "Invalid handler fields configured for \"cacheHandlers\":\\n%s",
   "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
+  "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+  "905": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+  "906": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }
diff --git a/packages/next/src/build/analysis/get-page-static-info.ts b/packages/next/src/build/analysis/get-page-static-info.ts
index 30db844f6474a..a3d37846c65be 100644
--- a/packages/next/src/build/analysis/get-page-static-info.ts
+++ b/packages/next/src/build/analysis/get-page-static-info.ts
@@ -411,8 +411,7 @@ function validateMiddlewareProxyExports({
         `- There's a syntax error preventing the export from being recognized.\n\n` +
         `To fix it:\n` +
         `- Check your "${relativeFilePath}" file.\n` +
-        `- Ensure it has either a default or "${fileName}" function export.\n` +
-        `- Restart the dev server if the error persists.\n\n` +
+        `- Ensure it has either a default or "${fileName}" function export.\n\n` +
         `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
     )
   }
diff --git a/packages/next/src/build/templates/middleware.ts b/packages/next/src/build/templates/middleware.ts
index d30f7d8098867..2129918b93b1d 100644
--- a/packages/next/src/build/templates/middleware.ts
+++ b/packages/next/src/build/templates/middleware.ts
@@ -37,8 +37,7 @@ if (typeof handler !== 'function') {
       `- There's a syntax error preventing the export from being recognized.\n\n` +
       `To fix it:\n` +
       `- Check your "${resolvedRelativeFilePath}" file.\n` +
-      `- Ensure it has either a default or "${fileName}" function export.\n` +
-      `- Restart the dev server if the error persists.\n\n` +
+      `- Ensure it has either a default or "${fileName}" function export.\n\n` +
       `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
   )
 }
diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index 4b9ad4debf45b..f07df743188ef 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -14,7 +14,6 @@ Why this happens:
 To fix it:
 - Check your "./proxy.ts" file.
 - Ensure it has either a default or "proxy" function export.
-- Restart the dev server if the error persists.
 
 Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
 

From 52c8fcfb82f18c0db9b1c88008493d9f3061edce Mon Sep 17 00:00:00 2001
From: Niklas Mischkulnig <4586894+mischnic@users.noreply.github.com>
Date: Mon, 20 Oct 2025 15:31:03 -0700
Subject: [PATCH 06/11] Cleanup Turbopack and error message

---
 crates/next-core/src/middleware.rs            | 48 ++++---------------
 packages/next/errors.json                     |  3 +-
 .../build/analysis/get-page-static-info.ts    |  3 +-
 .../next/src/build/templates/middleware.ts    |  3 +-
 .../proxy-missing-export.test.ts              | 39 +++++++++++----
 5 files changed, 42 insertions(+), 54 deletions(-)

diff --git a/crates/next-core/src/middleware.rs b/crates/next-core/src/middleware.rs
index fe17fb9f699ab..56845fd72accf 100644
--- a/crates/next-core/src/middleware.rs
+++ b/crates/next-core/src/middleware.rs
@@ -1,7 +1,4 @@
-use std::env;
-
 use anyhow::Result;
-use pathdiff::diff_paths;
 use turbo_rcstr::{RcStr, rcstr};
 use turbo_tasks::{ResolvedVc, Vc, fxindexmap};
 use turbo_tasks_fs::FileSystemPath;
@@ -125,30 +122,6 @@ struct MiddlewareMissingExportIssue {
     file_path: FileSystemPath,
 }
 
-impl MiddlewareMissingExportIssue {
-    fn get_relative_path(&self) -> String {
-        // Get relative path from current working directory (like process.cwd() in JavaScript)
-        let cwd = env::current_dir().ok();
-        let file_path_str = self.file_path.path.as_str();
-        let relative_path = if let Some(cwd) = cwd {
-            diff_paths(file_path_str, cwd)
-                .and_then(|p| p.to_str().map(|s| s.to_string()))
-                .unwrap_or_else(|| self.file_path.file_name().to_string())
-        } else {
-            self.file_path.file_name().to_string()
-        };
-        format!("./{}", relative_path)
-    }
-
-    fn get_type_description(&self) -> &str {
-        if self.file_type.as_str() == "Proxy" {
-            "proxy (previously called middleware)"
-        } else {
-            "middleware"
-        }
-    }
-}
-
 #[turbo_tasks::value_impl]
 impl Issue for MiddlewareMissingExportIssue {
     #[turbo_tasks::function]
@@ -167,13 +140,9 @@ impl Issue for MiddlewareMissingExportIssue {
 
     #[turbo_tasks::function]
     async fn title(&self) -> Result<Vc<StyledString>> {
-        let relative_path_str = self.get_relative_path();
-
-        // Only the first line goes in title to avoid formatIssue indentation
         let title_text = format!(
-            "The file \"{}\" must export a function, either as a default export or as a named \
-             \"{}\" export.",
-            relative_path_str, self.function_name
+            "{} is missing expected function export name",
+            self.file_type
         );
 
         Ok(StyledString::Text(title_text.into()).cell())
@@ -181,10 +150,13 @@ impl Issue for MiddlewareMissingExportIssue {
 
     #[turbo_tasks::function]
     async fn description(&self) -> Result<Vc<OptionStyledString>> {
-        let relative_path_str = self.get_relative_path();
-        let type_description = self.get_type_description();
+        let type_description = if self.file_type == "Proxy" {
+            "proxy (previously called middleware)"
+        } else {
+            "middleware"
+        };
 
-        let migration_bullet = if self.file_type.as_str() == "Proxy" {
+        let migration_bullet = if self.file_type == "Proxy" {
             "- You are migrating from `middleware` to `proxy`, but haven't updated the exported \
              function.\n"
         } else {
@@ -200,12 +172,10 @@ impl Issue for MiddlewareMissingExportIssue {
              - The export is not a function (e.g., an object or constant).\n\
              - There's a syntax error preventing the export from being recognized.\n\n\
              To fix it:\n\
-             - Check your \"{}\" file.\n\
-             - Ensure it has either a default or \"{}\" function export.\n\n\
+             - Ensure this file has either a default or \"{}\" function export.\n\n\
              Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
             type_description,
             migration_bullet,
-            relative_path_str,
             self.function_name
         );
 
diff --git a/packages/next/errors.json b/packages/next/errors.json
index 86b9beb0920cd..5b0bb64faae02 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -904,5 +904,6 @@
   "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "905": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "906": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
+  "906": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+  "907": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }
diff --git a/packages/next/src/build/analysis/get-page-static-info.ts b/packages/next/src/build/analysis/get-page-static-info.ts
index a3d37846c65be..01314d1449e2e 100644
--- a/packages/next/src/build/analysis/get-page-static-info.ts
+++ b/packages/next/src/build/analysis/get-page-static-info.ts
@@ -410,8 +410,7 @@ function validateMiddlewareProxyExports({
         `- The export is not a function (e.g., an object or constant).\n` +
         `- There's a syntax error preventing the export from being recognized.\n\n` +
         `To fix it:\n` +
-        `- Check your "${relativeFilePath}" file.\n` +
-        `- Ensure it has either a default or "${fileName}" function export.\n\n` +
+        `- Ensure this file has either a default or "${fileName}" function export.\n\n` +
         `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
     )
   }
diff --git a/packages/next/src/build/templates/middleware.ts b/packages/next/src/build/templates/middleware.ts
index 2129918b93b1d..376c63a8d4e61 100644
--- a/packages/next/src/build/templates/middleware.ts
+++ b/packages/next/src/build/templates/middleware.ts
@@ -36,8 +36,7 @@ if (typeof handler !== 'function') {
       `- The export is not a function (e.g., an object or constant).\n` +
       `- There's a syntax error preventing the export from being recognized.\n\n` +
       `To fix it:\n` +
-      `- Check your "${resolvedRelativeFilePath}" file.\n` +
-      `- Ensure it has either a default or "${fileName}" function export.\n\n` +
+      `- Ensure this file has either a default or "${fileName}" function export.\n` +
       `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
   )
 }
diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index f07df743188ef..4c6d2c6b2b2ea 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -2,8 +2,7 @@ import { nextTestSetup } from 'e2e-utils'
 import { join } from 'node:path'
 import { writeFile } from 'node:fs/promises'
 
-const errorMessage = `The file "./proxy.ts" must export a function, either as a default export or as a named "proxy" export.
-This function is what Next.js runs for every request handled by this proxy (previously called middleware).
+const errorMessage = `This function is what Next.js runs for every request handled by this proxy (previously called middleware).
 
 Why this happens:
 - You are migrating from \`middleware\` to \`proxy\`, but haven't updated the exported function.
@@ -12,8 +11,7 @@ Why this happens:
 - There's a syntax error preventing the export from being recognized.
 
 To fix it:
-- Check your "./proxy.ts" file.
-- Ensure it has either a default or "proxy" function export.
+- Ensure this file has either a default or "proxy" function export.
 
 Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
 
@@ -34,14 +32,25 @@ describe('proxy-missing-export', () => {
       'export function middleware() {}'
     )
 
+    let cliOutput: string
+
     if (isNextDev) {
       await next.start().catch(() => {})
       // Use .catch() because Turbopack errors during compile and exits before runtime.
       await next.browser('/').catch(() => {})
-      expect(next.cliOutput).toContain(errorMessage)
+      cliOutput = next.cliOutput
+    } else {
+      cliOutput = (await next.build()).cliOutput
+    }
+
+    if (process.env.IS_TURBOPACK_TEST) {
+      expect(cliOutput).toContain(`./proxy.ts
+Proxy is missing expected function export name
+${errorMessage}`)
     } else {
-      const { cliOutput } = await next.build()
-      expect(cliOutput).toContain(errorMessage)
+      expect(cliOutput)
+        .toContain(`The file "./proxy.ts" must export a function, either as a default export or as a named "proxy" export.
+${errorMessage}`)
     }
 
     await next.stop()
@@ -106,16 +115,26 @@ describe('proxy-missing-export', () => {
       'const proxy = () => {}; export { proxy as handler };'
     )
 
+    let cliOutput: string
+
     if (isNextDev) {
       await next.start().catch(() => {})
       // Use .catch() because Turbopack errors during compile and exits before runtime.
       await next.browser('/').catch(() => {})
-      expect(next.cliOutput).toContain(errorMessage)
+      cliOutput = next.cliOutput
     } else {
-      const { cliOutput } = await next.build()
-      expect(cliOutput).toContain(errorMessage)
+      cliOutput = (await next.build()).cliOutput
     }
 
+    if (process.env.IS_TURBOPACK_TEST) {
+      expect(cliOutput).toContain(`./proxy.ts
+Proxy is missing expected function export name
+${errorMessage}`)
+    } else {
+      expect(cliOutput)
+        .toContain(`The file "./proxy.ts" must export a function, either as a default export or as a named "proxy" export.
+${errorMessage}`)
+    }
     await next.stop()
   })
 })

From 9171a98a62ee7d20964a8b101cbdad52a3eab57b Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Mon, 20 Oct 2025 22:54:31 -0700
Subject: [PATCH 07/11] Fix errors.json and new line

---
 packages/next/errors.json                       | 3 ++-
 packages/next/src/build/templates/middleware.ts | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/packages/next/errors.json b/packages/next/errors.json
index 5b0bb64faae02..696091a222846 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -905,5 +905,6 @@
   "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "905": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "906": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "907": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
+  "907": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
+  "908": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }
diff --git a/packages/next/src/build/templates/middleware.ts b/packages/next/src/build/templates/middleware.ts
index 376c63a8d4e61..2637bd64dffaa 100644
--- a/packages/next/src/build/templates/middleware.ts
+++ b/packages/next/src/build/templates/middleware.ts
@@ -36,7 +36,7 @@ if (typeof handler !== 'function') {
       `- The export is not a function (e.g., an object or constant).\n` +
       `- There's a syntax error preventing the export from being recognized.\n\n` +
       `To fix it:\n` +
-      `- Ensure this file has either a default or "${fileName}" function export.\n` +
+      `- Ensure this file has either a default or "${fileName}" function export.\n\n` +
       `Learn more: https://nextjs.org/docs/messages/middleware-to-proxy`
   )
 }

From 3bb7709b028451f7f7763eb47e31c25a90d292dc Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Tue, 21 Oct 2025 09:53:56 -0700
Subject: [PATCH 08/11] test: dev-turbo logs on browser only not terminal

---
 .../app-dir/proxy-missing-export/proxy-missing-export.test.ts  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index 4c6d2c6b2b2ea..f3a0c14514dec 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -43,7 +43,8 @@ describe('proxy-missing-export', () => {
       cliOutput = (await next.build()).cliOutput
     }
 
-    if (process.env.IS_TURBOPACK_TEST) {
+    // TODO: Investigate why in dev-turbo, the error is shown in the browser console, not CLI output.
+    if (process.env.IS_TURBOPACK_TEST && !isNextDev) {
       expect(cliOutput).toContain(`./proxy.ts
 Proxy is missing expected function export name
 ${errorMessage}`)

From afac100eff149d328a806b8e78187b06700e23bb Mon Sep 17 00:00:00 2001
From: Jiwon Choi <devjiwonchoi@gmail.com>
Date: Tue, 21 Oct 2025 10:15:15 -0700
Subject: [PATCH 09/11] test: dev-turbo logs on browser only not terminal

---
 .../app-dir/proxy-missing-export/proxy-missing-export.test.ts  | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
index f3a0c14514dec..92faf1c94e5b2 100644
--- a/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
+++ b/test/e2e/app-dir/proxy-missing-export/proxy-missing-export.test.ts
@@ -127,7 +127,8 @@ ${errorMessage}`)
       cliOutput = (await next.build()).cliOutput
     }
 
-    if (process.env.IS_TURBOPACK_TEST) {
+    // TODO: Investigate why in dev-turbo, the error is shown in the browser console, not CLI output.
+    if (process.env.IS_TURBOPACK_TEST && !isNextDev) {
       expect(cliOutput).toContain(`./proxy.ts
 Proxy is missing expected function export name
 ${errorMessage}`)

From b293ddd0d0f4dc2568ced7065d4a62c3937c4d76 Mon Sep 17 00:00:00 2001
From: Jiwon Choi <devjiwonchoi@gmail.com>
Date: Tue, 21 Oct 2025 10:22:54 -0700
Subject: [PATCH 10/11] remove pathdiff

Co-authored-by: vercel[bot] <35613825+vercel[bot]@users.noreply.github.com>
---
 crates/next-core/Cargo.toml | 1 -
 1 file changed, 1 deletion(-)

diff --git a/crates/next-core/Cargo.toml b/crates/next-core/Cargo.toml
index 3b480e562a23d..90f77cbcd556f 100644
--- a/crates/next-core/Cargo.toml
+++ b/crates/next-core/Cargo.toml
@@ -15,7 +15,6 @@ workspace = true
 anyhow = { workspace = true }
 async-trait = { workspace = true }
 base64 = "0.21.0"
-pathdiff = { workspace = true }
 either = { workspace = true, features = ["serde"] }
 once_cell = { workspace = true }
 qstring = { workspace = true }

From 5923a411f9da6511ee2d4813fc38db31e46cadbf Mon Sep 17 00:00:00 2001
From: devjiwonchoi <devjiwonchoi@gmail.com>
Date: Tue, 21 Oct 2025 12:05:27 -0700
Subject: [PATCH 11/11] Update errors.json

---
 packages/next/errors.json | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/packages/next/errors.json b/packages/next/errors.json
index 696091a222846..cbe2d5256c427 100644
--- a/packages/next/errors.json
+++ b/packages/next/errors.json
@@ -901,10 +901,5 @@
   "900": "Both %s file \"./%s\" and %s file \"./%s\" are detected. Please use \"./%s\" only. Learn more: https://nextjs.org/docs/messages/middleware-to-proxy",
   "901": "Invalid \"cacheHandlers\" provided, expected an object e.g. { default: '/my-handler.js' }, received %s",
   "902": "Invalid handler fields configured for \"cacheHandlers\":\\n%s",
-  "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "904": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "905": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "906": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Check your \"%s\" file.\\n- Ensure it has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "907": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n- Restart the dev server if the error persists.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy",
-  "908": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
+  "903": "The file \"%s\" must export a function, either as a default export or as a named \"%s\" export.\\nThis function is what Next.js runs for every request handled by this %s.\\n\\nWhy this happens:\\n%s- The file exists but doesn't export a function.\\n- The export is not a function (e.g., an object or constant).\\n- There's a syntax error preventing the export from being recognized.\\n\\nTo fix it:\\n- Ensure this file has either a default or \"%s\" function export.\\n\\nLearn more: https://nextjs.org/docs/messages/middleware-to-proxy"
 }