From 46e9f48a941c96933da5859eec9222f7745933ce Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusan@google.com>
Date: Mon, 3 Mar 2025 15:38:28 +0000
Subject: [PATCH 01/28] add function to override next config

---
 packages/@apphosting/adapter-nextjs/src/bin/build.ts | 5 +++--
 packages/@apphosting/adapter-nextjs/src/overrides.ts | 6 ++++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
index a2241174..b86522bc 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
@@ -20,11 +20,12 @@ process.env.NEXT_TELEMETRY_DISABLED = "1";
 if (!process.env.FRAMEWORK_VERSION) {
   throw new Error("Could not find the nextjs version of the application");
 }
+
+const { distDir, configFileName } = await loadConfig(root, opts.projectDirectory);
+
 await runBuild();
 
 const adapterMetadata = getAdapterMetadata();
-
-const { distDir } = await loadConfig(root, opts.projectDirectory);
 const nextBuildDirectory = join(opts.projectDirectory, distDir);
 const outputBundleOptions = populateOutputBundleOptions(
   root,
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index d4672638..a16be049 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -1,6 +1,8 @@
 import { AdapterMetadata, MiddlewareManifest } from "./interfaces.js";
 import { loadRouteManifest, writeRouteManifest, loadMiddlewareManifest } from "./utils.js";
 
+export async function overrideNextConfig(nextConfigFileName: string) {}
+
 /**
  * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting
  * specific overrides (i.e headers).
@@ -36,8 +38,8 @@ export async function addRouteOverrides(
           ]
         : []),
     ],
-    /* 
-      NextJs converts the source string to a regex using path-to-regexp (https://github.com/pillarjs/path-to-regexp) at 
+    /*
+      NextJs converts the source string to a regex using path-to-regexp (https://github.com/pillarjs/path-to-regexp) at
       build time: https://github.com/vercel/next.js/blob/canary/packages/next/src/build/index.ts#L1273.
       This regex is then used to match the route against the request path.
 

From e4c1966aa470f2a5eea0d42de06eb9cbd5623f68 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Mon, 3 Mar 2025 16:37:51 -0500
Subject: [PATCH 02/28] implement next config override logic to import in
 existing config and export overrided config

---
 .../adapter-nextjs/src/bin/build.ts           |  4 +-
 .../adapter-nextjs/src/overrides.ts           | 77 ++++++++++++++++++-
 2 files changed, 77 insertions(+), 4 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
index b86522bc..8bf67aaf 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
@@ -8,7 +8,7 @@ import {
 } from "../utils.js";
 import { join } from "path";
 import { getBuildOptions, runBuild } from "@apphosting/common";
-import { addRouteOverrides } from "../overrides.js";
+import { addRouteOverrides, overrideNextConfig } from "../overrides.js";
 
 const root = process.cwd();
 const opts = getBuildOptions();
@@ -22,7 +22,7 @@ if (!process.env.FRAMEWORK_VERSION) {
 }
 
 const { distDir, configFileName } = await loadConfig(root, opts.projectDirectory);
-
+await overrideNextConfig(configFileName);
 await runBuild();
 
 const adapterMetadata = getAdapterMetadata();
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index a16be049..0912a16e 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -1,7 +1,80 @@
 import { AdapterMetadata, MiddlewareManifest } from "./interfaces.js";
-import { loadRouteManifest, writeRouteManifest, loadMiddlewareManifest } from "./utils.js";
+import {
+  loadRouteManifest,
+  writeRouteManifest,
+  loadMiddlewareManifest,
+  exists,
+  writeFile,
+} from "./utils.js";
+import { join } from "path";
+import { readFileSync } from "fs";
 
-export async function overrideNextConfig(nextConfigFileName: string) {}
+export async function overrideNextConfig(nextConfigFileName: string) {
+  // Check if the file exists in the current working directory
+  const cwd = process.cwd();
+  const configPath = join(cwd, nextConfigFileName);
+
+  if (!(await exists(configPath))) {
+    console.log(`No Next.js config file found at ${configPath}`);
+    return;
+  }
+
+  // Determine the file extension
+  const fileExtension = nextConfigFileName.split(".").pop() || "js";
+  const originalConfigName = `next.config.original.${fileExtension}`;
+  const newConfigName = `next.config.${fileExtension}`;
+
+  // Rename the original config file
+  try {
+    const originalContent = readFileSync(configPath, "utf-8");
+    await writeFile(join(cwd, originalConfigName), originalContent);
+
+    // Create a new config file with the appropriate import
+    let importStatement;
+    if (fileExtension === "js" || fileExtension === "cjs") {
+      importStatement = `const originalConfig = require('./${originalConfigName}');`;
+    } else if (fileExtension === "mjs") {
+      importStatement = `import originalConfig from './${originalConfigName}';`;
+    } else if (fileExtension === "ts") {
+      importStatement = `import originalConfig from './${originalConfigName.replace(".ts", "")}';`;
+    } else {
+      throw new Error(`Unsupported file extension: ${fileExtension}`);
+    }
+
+    // Create the new config content with our overrides
+    const newConfigContent = `${importStatement}
+
+// This file was automatically generated by Firebase App Hosting adapter
+const config = typeof originalConfig === 'function' 
+  ? (...args) => {
+      const resolvedConfig = originalConfig(...args);
+      return {
+        ...resolvedConfig,
+        images: {
+          ...(resolvedConfig.images || {}),
+          unoptimized: true,
+        },
+      };
+    }
+  : {
+      ...originalConfig,
+      images: {
+        ...(originalConfig.images || {}),
+        unoptimized: true,
+      },
+    };
+
+${fileExtension === "mjs" ? "export default config;" : "module.exports = config;"}
+`;
+
+    // Write the new config file
+    await writeFile(join(cwd, newConfigName), newConfigContent);
+    console.log(`Successfully created ${newConfigName} with Firebase App Hosting overrides`);
+  } catch (error) {
+    console.error(`Error overriding Next.js config: ${error}`);
+    throw error;
+  }
+}
 
 /**
  * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting

From 7924e7bd62186b088702011d9b1c6bec9e39f678 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Mon, 3 Mar 2025 23:43:19 -0500
Subject: [PATCH 03/28] add unit tests for next config overrides

---
 .../adapter-nextjs/src/bin/build.ts           |   2 +-
 .../adapter-nextjs/src/overrides.spec.ts      | 206 ++++++++++++++++++
 .../adapter-nextjs/src/overrides.ts           |   9 +-
 3 files changed, 211 insertions(+), 6 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
index 8bf67aaf..eb2e525a 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
@@ -22,7 +22,7 @@ if (!process.env.FRAMEWORK_VERSION) {
 }
 
 const { distDir, configFileName } = await loadConfig(root, opts.projectDirectory);
-await overrideNextConfig(configFileName);
+await overrideNextConfig(root, configFileName);
 await runBuild();
 
 const adapterMetadata = getAdapterMetadata();
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index b608717c..35e418ba 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -163,3 +163,209 @@ describe("route overrides", () => {
     fs.rmSync(tmpDir, { recursive: true, force: true });
   });
 });
+
+describe("next config overrides", () => {
+  let tmpDir: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-overrides"));
+  });
+
+  it("should set images.unoptimized to true - js normal config", async () => {
+    const { overrideNextConfig } = await importOverrides;
+    const originalConfig = `
+    // @ts-check
+ 
+    /** @type {import('next').NextConfig} */
+    const nextConfig = {
+      /* config options here */
+    }
+    
+    module.exports = nextConfig
+    `;
+
+    fs.writeFileSync(path.join(tmpDir, "next.config.js"), originalConfig);
+    await overrideNextConfig(tmpDir, "next.config.js");
+
+    const updatedConfig = fs.readFileSync(path.join(tmpDir, "next.config.js"), "utf-8");
+
+    assert.equal(
+      normalizeWhitespace(updatedConfig),
+      normalizeWhitespace(`
+      const originalConfig = require('./next.config.original.js');
+      
+      // This file was automatically generated by Firebase App Hosting adapter
+      const config = typeof originalConfig === 'function' 
+        ? (...args) => {
+            const resolvedConfig = originalConfig(...args);
+              return {
+                ...resolvedConfig,
+                images: {
+                  ...(resolvedConfig.images || {}),
+                  unoptimized: true,
+                },
+              };
+        }
+        : {
+            ...originalConfig,
+            images: {
+              ...(originalConfig.images || {}),
+              unoptimized: true,
+            },
+          };
+
+      module.exports = config;
+      `),
+    );
+  });
+
+  it("should set images.unoptimized to true - ECMAScript Modules", async () => {
+    const { overrideNextConfig } = await importOverrides;
+    const originalConfig = `
+    // @ts-check
+    
+    /**
+     * @type {import('next').NextConfig}
+     */
+    const nextConfig = {
+      /* config options here */
+    }
+    
+    export default nextConfig
+    `;
+
+    fs.writeFileSync(path.join(tmpDir, "next.config.mjs"), originalConfig);
+    await overrideNextConfig(tmpDir, "next.config.mjs");
+
+    const updatedConfig = fs.readFileSync(path.join(tmpDir, "next.config.mjs"), "utf-8");
+    assert.equal(
+      normalizeWhitespace(updatedConfig),
+      normalizeWhitespace(`
+      import originalConfig from './next.config.original.mjs';
+
+      // This file was automatically generated by Firebase App Hosting adapter
+      const config = typeof originalConfig === 'function' 
+        ? (...args) => {
+            const resolvedConfig = originalConfig(...args);
+            return {
+              ...resolvedConfig,
+              images: {
+                ...(resolvedConfig.images || {}),
+                unoptimized: true,
+              },
+            };
+        }
+        : {
+            ...originalConfig,
+            images: {
+              ...(originalConfig.images || {}),
+              unoptimized: true,
+            },
+          };
+      
+      export default config;
+      `),
+    );
+  });
+
+  it("should set images.unoptimized to true - ECMAScript Function", async () => {
+    const { overrideNextConfig } = await importOverrides;
+    const originalConfig = `
+    // @ts-check
+    
+    export default (phase, { defaultConfig }) => {
+      /**
+       * @type {import('next').NextConfig}
+       */
+      const nextConfig = {
+        /* config options here */
+      }
+      return nextConfig
+    }
+    `;
+
+    fs.writeFileSync(path.join(tmpDir, "next.config.mjs"), originalConfig);
+    await overrideNextConfig(tmpDir, "next.config.mjs");
+
+    const updatedConfig = fs.readFileSync(path.join(tmpDir, "next.config.mjs"), "utf-8");
+    assert.equal(
+      normalizeWhitespace(updatedConfig),
+      normalizeWhitespace(`
+      import originalConfig from './next.config.original.mjs';
+
+      // This file was automatically generated by Firebase App Hosting adapter
+      const config = typeof originalConfig === 'function' 
+        ? (...args) => {
+            const resolvedConfig = originalConfig(...args);
+            return {
+              ...resolvedConfig,
+              images: {
+                ...(resolvedConfig.images || {}),
+                unoptimized: true,
+              },
+            };
+          }
+        : {
+            ...originalConfig,
+            images: {
+              ...(originalConfig.images || {}),
+              unoptimized: true,
+            },
+          };
+      
+      export default config;
+      `),
+    );
+  });
+
+  it("should set images.unoptimized to true - TypeScript", async () => {
+    const { overrideNextConfig } = await importOverrides;
+    const originalConfig = `
+    import type { NextConfig } from 'next'
+    
+    const nextConfig: NextConfig = {
+      /* config options here */
+    }
+    
+    export default nextConfig
+    `;
+
+    fs.writeFileSync(path.join(tmpDir, "next.config.ts"), originalConfig);
+    await overrideNextConfig(tmpDir, "next.config.ts");
+
+    const updatedConfig = fs.readFileSync(path.join(tmpDir, "next.config.ts"), "utf-8");
+    assert.equal(
+      normalizeWhitespace(updatedConfig),
+      normalizeWhitespace(`
+      import originalConfig from './next.config.original';
+      
+      // This file was automatically generated by Firebase App Hosting adapter
+      const config = typeof originalConfig === 'function' 
+        ? (...args) => {
+            const resolvedConfig = originalConfig(...args);
+            return {
+              ...resolvedConfig,
+              images: {
+                ...(resolvedConfig.images || {}),
+                unoptimized: true,
+              },
+            };
+          }
+        : {
+            ...originalConfig,
+            images: {
+              ...(originalConfig.images || {}),
+              unoptimized: true,
+            },
+          };
+      
+      module.exports = config;
+      `),
+    );
+  });
+});
+
+// Normalize whitespace for comparison
+function normalizeWhitespace(str: string) {
+  return str.replace(/\s+/g, " ").trim();
+}
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index 0912a16e..dc0709eb 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -9,10 +9,9 @@ import {
 import { join } from "path";
 import { readFileSync } from "fs";
 
-export async function overrideNextConfig(nextConfigFileName: string) {
+export async function overrideNextConfig(projectRoot: string, nextConfigFileName: string) {
   // Check if the file exists in the current working directory
-  const cwd = process.cwd();
-  const configPath = join(cwd, nextConfigFileName);
+  const configPath = join(projectRoot, nextConfigFileName);
 
   if (!(await exists(configPath))) {
     console.log(`No Next.js config file found at ${configPath}`);
@@ -27,7 +26,7 @@ export async function overrideNextConfig(nextConfigFileName: string) {
   // Rename the original config file
   try {
     const originalContent = readFileSync(configPath, "utf-8");
-    await writeFile(join(cwd, originalConfigName), originalContent);
+    await writeFile(join(projectRoot, originalConfigName), originalContent);
 
     // Create a new config file with the appropriate import
     let importStatement;
@@ -68,7 +67,7 @@ ${fileExtension === "mjs" ? "export default config;" : "module.exports = config;
 `;
 
     // Write the new config file
-    await writeFile(join(cwd, newConfigName), newConfigContent);
+    await writeFile(join(projectRoot, newConfigName), newConfigContent);
     console.log(`Successfully created ${newConfigName} with Firebase App Hosting overrides`);
   } catch (error) {
     console.error(`Error overriding Next.js config: ${error}`);

From b670497840128274a961d527e58d059077dc35d1 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Wed, 5 Mar 2025 17:25:29 -0500
Subject: [PATCH 04/28] address some comments

---
 .../adapter-nextjs/src/overrides.spec.ts      | 103 +++++-------------
 .../adapter-nextjs/src/overrides.ts           |  52 +++++----
 2 files changed, 54 insertions(+), 101 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index 35e418ba..2291f990 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -166,6 +166,23 @@ describe("route overrides", () => {
 
 describe("next config overrides", () => {
   let tmpDir: string;
+  const nextConfigOverrideBody = `
+     // This file was automatically generated by Firebase App Hosting adapter
+    const fahOptimizedConfig = (config) => ({
+      ...config,
+      images: {
+        ...(config.images || {}),
+        ...(config.images?.unoptimized === undefined ? { unoptimized: true } : {}),
+      },
+    });
+
+    const config = typeof originalConfig === 'function' 
+      ? (...args) => {
+          const resolvedConfig = originalConfig(...args);
+          return fahOptimizedConfig(resolvedConfig);
+        }
+      : fahOptimizedConfig(originalConfig);
+      `;
 
   beforeEach(() => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-overrides"));
@@ -192,27 +209,10 @@ describe("next config overrides", () => {
     assert.equal(
       normalizeWhitespace(updatedConfig),
       normalizeWhitespace(`
+      // @ts-nocheck
       const originalConfig = require('./next.config.original.js');
       
-      // This file was automatically generated by Firebase App Hosting adapter
-      const config = typeof originalConfig === 'function' 
-        ? (...args) => {
-            const resolvedConfig = originalConfig(...args);
-              return {
-                ...resolvedConfig,
-                images: {
-                  ...(resolvedConfig.images || {}),
-                  unoptimized: true,
-                },
-              };
-        }
-        : {
-            ...originalConfig,
-            images: {
-              ...(originalConfig.images || {}),
-              unoptimized: true,
-            },
-          };
+      ${nextConfigOverrideBody}
 
       module.exports = config;
       `),
@@ -241,28 +241,11 @@ describe("next config overrides", () => {
     assert.equal(
       normalizeWhitespace(updatedConfig),
       normalizeWhitespace(`
+      // @ts-nocheck
       import originalConfig from './next.config.original.mjs';
 
-      // This file was automatically generated by Firebase App Hosting adapter
-      const config = typeof originalConfig === 'function' 
-        ? (...args) => {
-            const resolvedConfig = originalConfig(...args);
-            return {
-              ...resolvedConfig,
-              images: {
-                ...(resolvedConfig.images || {}),
-                unoptimized: true,
-              },
-            };
-        }
-        : {
-            ...originalConfig,
-            images: {
-              ...(originalConfig.images || {}),
-              unoptimized: true,
-            },
-          };
-      
+      ${nextConfigOverrideBody}
+
       export default config;
       `),
     );
@@ -291,27 +274,10 @@ describe("next config overrides", () => {
     assert.equal(
       normalizeWhitespace(updatedConfig),
       normalizeWhitespace(`
+      // @ts-nocheck
       import originalConfig from './next.config.original.mjs';
 
-      // This file was automatically generated by Firebase App Hosting adapter
-      const config = typeof originalConfig === 'function' 
-        ? (...args) => {
-            const resolvedConfig = originalConfig(...args);
-            return {
-              ...resolvedConfig,
-              images: {
-                ...(resolvedConfig.images || {}),
-                unoptimized: true,
-              },
-            };
-          }
-        : {
-            ...originalConfig,
-            images: {
-              ...(originalConfig.images || {}),
-              unoptimized: true,
-            },
-          };
+      ${nextConfigOverrideBody}
       
       export default config;
       `),
@@ -337,27 +303,10 @@ describe("next config overrides", () => {
     assert.equal(
       normalizeWhitespace(updatedConfig),
       normalizeWhitespace(`
+      // @ts-nocheck
       import originalConfig from './next.config.original';
       
-      // This file was automatically generated by Firebase App Hosting adapter
-      const config = typeof originalConfig === 'function' 
-        ? (...args) => {
-            const resolvedConfig = originalConfig(...args);
-            return {
-              ...resolvedConfig,
-              images: {
-                ...(resolvedConfig.images || {}),
-                unoptimized: true,
-              },
-            };
-          }
-        : {
-            ...originalConfig,
-            images: {
-              ...(originalConfig.images || {}),
-              unoptimized: true,
-            },
-          };
+      ${nextConfigOverrideBody}
       
       module.exports = config;
       `),
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index dc0709eb..8c40c07a 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -41,30 +41,7 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
     }
 
     // Create the new config content with our overrides
-    const newConfigContent = `${importStatement}
-
-// This file was automatically generated by Firebase App Hosting adapter
-const config = typeof originalConfig === 'function' 
-  ? (...args) => {
-      const resolvedConfig = originalConfig(...args);
-      return {
-        ...resolvedConfig,
-        images: {
-          ...(resolvedConfig.images || {}),
-          unoptimized: true,
-        },
-      };
-    }
-  : {
-      ...originalConfig,
-      images: {
-        ...(originalConfig.images || {}),
-        unoptimized: true,
-      },
-    };
-
-${fileExtension === "mjs" ? "export default config;" : "module.exports = config;"}
-`;
+    const newConfigContent = getCustomNextConfig(importStatement, fileExtension);
 
     // Write the new config file
     await writeFile(join(projectRoot, newConfigName), newConfigContent);
@@ -75,6 +52,33 @@ ${fileExtension === "mjs" ? "export default config;" : "module.exports = config;
   }
 }
 
+function getCustomNextConfig(importStatement: string, fileExtension: string) {
+  return `
+  // @ts-nocheck
+  ${importStatement}
+
+  // This file was automatically generated by Firebase App Hosting adapter
+  const fahOptimizedConfig = (config) => ({
+    ...config,
+    images: {
+      ...(config.images || {}),
+      ...(config.images?.unoptimized === undefined && config.images?.loader === undefined 
+          ? { unoptimized: true } 
+          : {}),
+    },
+  });
+
+  const config = typeof originalConfig === 'function' 
+    ? (...args) => {
+        const resolvedConfig = originalConfig(...args);
+        return fahOptimizedConfig(resolvedConfig);
+      }
+    : fahOptimizedConfig(originalConfig);
+
+  ${fileExtension === "mjs" ? "export default config;" : "module.exports = config;"}
+  `;
+}
+
 /**
  * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting
  * specific overrides (i.e headers).

From af99265fd5dc93fe6d1e4cca91605dfbecb4385c Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Wed, 5 Mar 2025 18:57:33 -0500
Subject: [PATCH 05/28] fix test

---
 .../adapter-nextjs/src/overrides.spec.ts      | 32 ++++++++++---------
 1 file changed, 17 insertions(+), 15 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index 2291f990..3efa78c3 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -167,22 +167,24 @@ describe("route overrides", () => {
 describe("next config overrides", () => {
   let tmpDir: string;
   const nextConfigOverrideBody = `
-     // This file was automatically generated by Firebase App Hosting adapter
-    const fahOptimizedConfig = (config) => ({
-      ...config,
-      images: {
-        ...(config.images || {}),
-        ...(config.images?.unoptimized === undefined ? { unoptimized: true } : {}),
-      },
-    });
+  // This file was automatically generated by Firebase App Hosting adapter
+  const fahOptimizedConfig = (config) => ({
+    ...config,
+    images: {
+      ...(config.images || {}),
+      ...(config.images?.unoptimized === undefined && config.images?.loader === undefined 
+          ? { unoptimized: true } 
+          : {}),
+    },
+  });
 
-    const config = typeof originalConfig === 'function' 
-      ? (...args) => {
-          const resolvedConfig = originalConfig(...args);
-          return fahOptimizedConfig(resolvedConfig);
-        }
-      : fahOptimizedConfig(originalConfig);
-      `;
+  const config = typeof originalConfig === 'function' 
+    ? (...args) => {
+        const resolvedConfig = originalConfig(...args);
+        return fahOptimizedConfig(resolvedConfig);
+      }
+    : fahOptimizedConfig(originalConfig);
+    `;
 
   beforeEach(() => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-overrides"));

From c6626f93f7f6faba955ee0966e45d4fae971c991 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Wed, 5 Mar 2025 19:07:08 -0500
Subject: [PATCH 06/28] use rename instead of read/write

---
 packages/@apphosting/adapter-nextjs/src/overrides.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index 8c40c07a..a663bef4 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -7,7 +7,7 @@ import {
   writeFile,
 } from "./utils.js";
 import { join } from "path";
-import { readFileSync } from "fs";
+import { rename as renamePromise } from "fs/promises";
 
 export async function overrideNextConfig(projectRoot: string, nextConfigFileName: string) {
   // Check if the file exists in the current working directory
@@ -25,8 +25,8 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
 
   // Rename the original config file
   try {
-    const originalContent = readFileSync(configPath, "utf-8");
-    await writeFile(join(projectRoot, originalConfigName), originalContent);
+    const originalPath = join(projectRoot, originalConfigName);
+    await renamePromise(configPath, originalPath);
 
     // Create a new config file with the appropriate import
     let importStatement;

From 4a8401a4c17bea95c9aebdf493f845a0be7f5762 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 00:06:40 -0500
Subject: [PATCH 07/28] progress - e2e tests

---
 .../e2e/config-override.spec.ts               | 191 ++++++++++++++++++
 .../adapter-nextjs/e2e/run-local.ts           | 159 +++++++++++++--
 2 files changed, 330 insertions(+), 20 deletions(-)
 create mode 100644 packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts

diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
new file mode 100644
index 00000000..2393c505
--- /dev/null
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
@@ -0,0 +1,191 @@
+import * as assert from "assert";
+import { posix } from "path";
+import fsExtra from "fs-extra";
+
+const host = process.env.HOST;
+if (!host) {
+  throw new Error("HOST environment variable expected");
+}
+
+const scenario = process.env.SCENARIO;
+if (!scenario) {
+  throw new Error("SCENARIO environment variable expected");
+}
+
+const runId = process.env.RUN_ID;
+if (!runId) {
+  throw new Error("RUN_ID environment variable expected");
+}
+
+describe("next.config override", () => {
+  it("should have images optimization disabled", async () => {
+    const serverFiles = await fsExtra.readJson(
+      `${process.cwd()}/e2e/runs/${runId}/.next/standalone/.next/required-server-files.json`,
+    );
+    console.log(`serverFiles: ${JSON.stringify(serverFiles)}`);
+    const config = serverFiles.config;
+
+    // Verify that images.unoptimized is set to true
+    assert.ok(config.images, "Config should have images property");
+    assert.strictEqual(
+      config.images.unoptimized,
+      true,
+      "Images should have unoptimized set to true",
+    );
+  });
+
+  // it("should preserve user config settings", async () => {
+  //   // This test checks if the user's original config settings are preserved
+  //   // We'll check for the custom header that was set in the next.config
+  //   const response = await fetch(posix.join(host, "/"));
+  //   assert.ok(response.ok);
+
+  //   // Check for the custom header that was set in the next.config
+  //   if (scenario.includes("with-js-config")) {
+  //     assert.equal(response.headers.get("x-custom-header") ?? "", "js-config-value");
+  //   } else if (scenario.includes("with-ts-config")) {
+  //     assert.equal(response.headers.get("x-custom-header") ?? "", "ts-config-value");
+  //   } else if (scenario.includes("with-mjs-config")) {
+  //     assert.equal(response.headers.get("x-custom-header") ?? "", "mjs-config-value");
+  //   } else if (scenario.includes("with-complex-config")) {
+  //     assert.equal(response.headers.get("x-custom-header") ?? "", "complex-config-value");
+  //   }
+  // });
+
+  // it("should handle function-style config correctly", async () => {
+  //   // Only run this test for scenarios with function-style config
+  //   if (!scenario.includes("function-style")) {
+  //     this.skip();
+  //     return;
+  //   }
+
+  //   // Check for the custom header that indicates function-style config was processed correctly
+  //   const response = await fetch(posix.join(host, "/"));
+  //   assert.ok(response.ok);
+  //   assert.equal(response.headers.get("x-config-type") ?? "", "function");
+  // });
+
+  // it("should handle object-style config correctly", async () => {
+  //   // Only run this test for scenarios with object-style config
+  //   if (
+  //     !scenario.includes("object-style") &&
+  //     !scenario.includes("with-complex-config") &&
+  //     !scenario.includes("with-empty-config")
+  //   ) {
+  //     this.skip();
+  //     return;
+  //   }
+
+  //   // Check for the custom header that indicates object-style config was processed correctly
+  //   const response = await fetch(posix.join(host, "/"));
+  //   assert.ok(response.ok);
+
+  //   // Empty config doesn't set this header
+  //   if (!scenario.includes("with-empty-config")) {
+  //     assert.equal(response.headers.get("x-config-type") ?? "", "object");
+  //   }
+  // });
+
+  // it("should handle empty config correctly", async () => {
+  //   // Only run this test for the empty config scenario
+  //   if (!scenario.includes("with-empty-config")) {
+  //     this.skip();
+  //     return;
+  //   }
+
+  //   // Just check that the page loads successfully
+  //   const response = await fetch(posix.join(host, "/"));
+  //   assert.ok(response.ok);
+  // });
+
+  // it("should verify original config file was preserved", async () => {
+  //   // This test verifies that the original config file was preserved
+  //   // We'll check the file system to make sure the original config file exists
+  //   let originalConfigExists = false;
+
+  //   if (scenario.includes("with-js-config")) {
+  //     originalConfigExists = await fsExtra.pathExists("next.config.original.js");
+  //   } else if (scenario.includes("with-ts-config")) {
+  //     originalConfigExists = await fsExtra.pathExists("next.config.original.ts");
+  //   } else if (scenario.includes("with-mjs-config")) {
+  //     originalConfigExists = await fsExtra.pathExists("next.config.original.mjs");
+  //   } else if (
+  //     scenario.includes("with-empty-config") ||
+  //     scenario.includes("with-complex-config") ||
+  //     scenario.includes("with-error-handling")
+  //   ) {
+  //     originalConfigExists = await fsExtra.pathExists("next.config.original.js");
+  //   }
+
+  //   assert.ok(originalConfigExists, "Original config file should be preserved");
+  // });
+
+  // it("should handle error gracefully when config file has syntax errors", async () => {
+  //   // Only run this test for the error handling scenario
+  //   if (!scenario.includes("with-error-handling")) {
+  //     this.skip();
+  //     return;
+  //   }
+
+  //   // The build should have succeeded despite the invalid config file
+  //   // because we started with a valid config
+  //   const response = await fetch(posix.join(host, "/"));
+  //   assert.ok(response.ok);
+
+  //   // Check if the invalid config file exists
+  //   const invalidConfigExists = await fsExtra.pathExists("next.config.invalid.js");
+  //   assert.ok(invalidConfigExists, "Invalid config file should exist");
+  // });
+
+  // it("should verify the generated config file has the correct format", async () => {
+  //   // Skip for error handling scenario
+  //   if (scenario.includes("with-error-handling")) {
+  //     this.skip();
+  //     return;
+  //   }
+
+  //   let configPath = "";
+
+  //   if (scenario.includes("with-js-config")) {
+  //     configPath = "next.config.js";
+  //   } else if (scenario.includes("with-ts-config")) {
+  //     configPath = "next.config.ts";
+  //   } else if (scenario.includes("with-mjs-config")) {
+  //     configPath = "next.config.mjs";
+  //   } else if (scenario.includes("with-empty-config") || scenario.includes("with-complex-config")) {
+  //     configPath = "next.config.js";
+  //   }
+
+  //   // Check if the generated config file exists
+  //   const configExists = await fsExtra.pathExists(configPath);
+  //   assert.ok(configExists, "Generated config file should exist");
+
+  //   // Read the config file content
+  //   const configContent = await fsExtra.readFile(configPath, "utf-8");
+
+  //   // Verify that the config file contains the unoptimized: true setting
+  //   assert.ok(configContent.includes("unoptimized: true"), "Config should have unoptimized: true");
+
+  //   // Verify that the config file imports the original config
+  //   if (
+  //     scenario.includes("with-js-config") ||
+  //     scenario.includes("with-empty-config") ||
+  //     scenario.includes("with-complex-config")
+  //   ) {
+  //     assert.ok(
+  //       configContent.includes("require('./next.config.original.js')"),
+  //       "Config should import the original JS config",
+  //     );
+  //   } else if (scenario.includes("with-ts-config")) {
+  //     assert.ok(
+  //       configContent.includes("import originalConfig from './next.config.original'"),
+  //       "Config should import the original TS config",
+  //     );
+  //   } else if (scenario.includes("with-mjs-config")) {
+  //     assert.ok(
+  //       configContent.includes("import originalConfig from './next.config.original.mjs'"),
+  //       "Config should import the original MJS config",
+  //     );
+  //   }
+  // });
+});
diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index abc44bd4..2dde98c9 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -20,33 +20,151 @@ interface Scenario {
 }
 
 const scenarios: Scenario[] = [
-  {
-    name: "basic",
-    // No setup needed for basic scenario
-    tests: ["app.spec.ts"],
-  },
-  {
-    name: "with-middleware",
-    setup: async (cwd: string) => {
-      // Create a middleware.ts file
-      const middlewareContent = `
-        import type { NextRequest } from 'next/server'
+  // {
+  //   name: "basic",
+  //   // No setup needed for basic scenario
+  //   tests: ["app.spec.ts"],
+  // },
+  // {
+  //   name: "with-middleware",
+  //   setup: async (cwd: string) => {
+  //     // Create a middleware.ts file
+  //     const middlewareContent = `
+  //       import type { NextRequest } from 'next/server'
+
+  //       export function middleware(request: NextRequest) {
+  //         // This is a simple middleware that doesn't modify the request
+  //         console.log('Middleware executed', request.nextUrl.pathname);
+  //       }
 
-        export function middleware(request: NextRequest) {
-          // This is a simple middleware that doesn't modify the request
-          console.log('Middleware executed', request.nextUrl.pathname);
-        }
+  //       export const config = {
+  //         matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
+  //       };
+  //     `;
 
-        export const config = {
-          matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
+  //     await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
+  //     console.log(`Created middleware.ts file`);
+  //   },
+  //   tests: ["middleware.spec.ts"], // Only run middleware-specific tests
+  // },
+  // New scenarios for testing Next.js config override behavior
+  {
+    name: "with-js-config-object-style",
+    setup: async (cwd: string) => {
+      // Create a next.config.js file with object-style config
+      const configContent = `
+        /** @type {import('next').NextConfig} */
+        const nextConfig = {
+          reactStrictMode: true,
+          async headers() {
+            return [
+              {
+                source: '/:path*',
+                headers: [
+                  {
+                    key: 'x-custom-header',
+                    value: 'js-config-value',
+                  },
+                  {
+                    key: 'x-config-type',
+                    value: 'object',
+                  },
+                ],
+              },
+            ];
+          },
         };
+        
+        module.exports = nextConfig;
       `;
 
-      await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
-      console.log(`Created middleware.ts file`);
+      await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
+      console.log(`Created next.config.js file with object-style config`);
     },
-    tests: ["middleware.spec.ts"], // Only run middleware-specific tests
+    tests: ["config-override.spec.ts"],
   },
+  // {
+  //   name: "with-js-config-object-style",
+  //   setup: async (cwd: string) => {
+  //     // Create a next.config.js file with object-style config
+  //     const configContent = `
+  //       /** @type {import('next').NextConfig} */
+  //       const nextConfig = {
+  //         reactStrictMode: true,
+  //         async headers() {
+  //           return [
+  //             {
+  //               source: '/:path*',
+  //               headers: [
+  //                 {
+  //                   key: 'x-custom-header',
+  //                   value: 'js-config-value',
+  //                 },
+  //                 {
+  //                   key: 'x-config-type',
+  //                   value: 'object',
+  //                 },
+  //               ],
+  //             },
+  //           ];
+  //         },
+  //         // This should be overridden by the adapter
+  //         images: {
+  //           unoptimized: false,
+  //           domains: ['example.com'],
+  //         },
+  //       };
+
+  //       module.exports = nextConfig;
+  //     `;
+
+  //     await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
+  //     console.log(`Created next.config.js file with object-style config`);
+  //   },
+  //   tests: ["config-override.spec.ts"],
+  // },
+  // {
+  //   name: "with-js-config-function-style",
+  //   setup: async (cwd: string) => {
+  //     // Create a next.config.js file with function-style config
+  //     const configContent = `
+  //       /** @type {import('next').NextConfig} */
+  //       const nextConfig = (phase, { defaultConfig }) => {
+  //         return {
+  //           reactStrictMode: true,
+  //           async headers() {
+  //             return [
+  //               {
+  //                 source: '/:path*',
+  //                 headers: [
+  //                   {
+  //                     key: 'x-custom-header',
+  //                     value: 'js-config-value',
+  //                   },
+  //                   {
+  //                     key: 'x-config-type',
+  //                     value: 'function',
+  //                   },
+  //                 ],
+  //               },
+  //             ];
+  //           },
+  //           // This should be overridden by the adapter
+  //           images: {
+  //             unoptimized: false,
+  //             domains: ['example.com'],
+  //           },
+  //         };
+  //       };
+
+  //       module.exports = nextConfig;
+  //     `;
+
+  //     await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
+  //     console.log(`Created next.config.js file with function-style config`);
+  //   },
+  //   tests: ["config-override.spec.ts"],
+  // },
 ];
 
 const errors: any[] = [];
@@ -170,6 +288,7 @@ for (const scenario of scenarios) {
           ...process.env,
           HOST: host,
           SCENARIO: scenario.name,
+          RUN_ID: runId,
         },
       }).finally(() => {
         run.stdin.end();

From 074d6a0b20234135d2a0ebcf1fc6a6e327b66a2f Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 13:01:04 -0500
Subject: [PATCH 08/28] mostly working e2e tests

---
 .../e2e/config-override-test-cases.yaml       | 144 +++++++++++
 .../e2e/config-override.spec.ts               | 237 ++++++------------
 .../adapter-nextjs/e2e/run-local.ts           | 144 ++---------
 3 files changed, 245 insertions(+), 280 deletions(-)
 create mode 100644 packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml

diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
new file mode 100644
index 00000000..c9ff6a7f
--- /dev/null
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
@@ -0,0 +1,144 @@
+tests:
+  # - name: with-js-config-object-style
+  #   config: |
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = {
+  #       reactStrictMode: true,
+  #       async headers() {
+  #         return [
+  #           {
+  #             source: '/:path*',
+  #             headers: [
+  #               {
+  #                 key: 'x-custom-header',
+  #                 value: 'js-config-value',
+  #               },
+  #               {
+  #                 key: 'x-config-type',
+  #                 value: 'object',
+  #               },
+  #             ],
+  #           },
+  #         ];
+  #       },
+  #     };
+
+  #     module.exports = nextConfig;
+  #   file: next.config.js
+  # - name: with-js-config-function-style
+  #   config: |
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = (phase, { defaultConfig }) => {
+  #       return {
+  #         reactStrictMode: true,
+  #         async headers() {
+  #           return [
+  #             {
+  #               source: '/:path*',
+  #               headers: [
+  #                 {
+  #                   key: 'x-custom-header',
+  #                   value: 'js-config-value',
+  #                 },
+  #                 {
+  #                   key: 'x-config-type',
+  #                   value: 'function',
+  #                 },
+  #               ],
+  #             },
+  #           ];
+  #         }
+  #       };
+  #     };
+
+  #     module.exports = nextConfig;
+  #   file: next.config.js
+  - name: with-js-async-function
+    config: |
+      // @ts-check
+
+      module.exports = async (phase, { defaultConfig }) => {
+        /**
+        * @type {import('next').NextConfig}
+        */
+        const nextConfig = {
+          async headers() {
+            return [
+              {
+                source: '/:path*',
+                headers: [
+                  {
+                    key: 'x-custom-header',
+                    value: 'js-config-value',
+                  },
+                  {
+                    key: 'x-config-type',
+                    value: 'function',
+                  },
+                ],
+              },
+            ];
+          }
+        }
+        return nextConfig
+      }
+    file: next.config.js
+  # - name: with-ts-config
+  #   config: |
+  #     import type { NextConfig } from 'next'
+
+  #     const nextConfig: NextConfig = {
+  #       async headers() {
+  #         return [
+  #           {
+  #             source: '/:path*',
+  #             headers: [
+  #               {
+  #                 key: 'x-custom-header',
+  #                 value: 'ts-config-value',
+  #               }
+  #             ],
+  #           },
+  #         ];
+  #       }
+  #     }
+
+  #     export default nextConfig
+  #   file: next.config.ts
+  # - name: with-ecmascript-modules
+  #   config: |
+  #     // @ts-check
+
+  #     /**
+  #     * @type {import('next').NextConfig}
+  #     */
+  #     const nextConfig = {
+  #       /* config options here */
+  #       async headers() {
+  #         return [
+  #           {
+  #             source: '/:path*',
+  #             headers: [
+  #               {
+  #                 key: 'x-custom-header',
+  #                 value: 'mjs-config-value',
+  #               },
+  #             ],
+  #           },
+  #         ];
+  #       }
+  #     }
+
+  #     export default nextConfig
+  #   file: next.config.mjs
+  # - name: with-empty-config
+  #   config: |
+  #     // @ts-check
+
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = {
+  #       /* config options here */
+  #     }
+
+  #     module.exports = nextConfig
+  #   file: next.config.js
diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
index 2393c505..b8fabeee 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
@@ -17,12 +17,23 @@ if (!runId) {
   throw new Error("RUN_ID environment variable expected");
 }
 
+const compiledFilesPath = posix.join(
+  process.cwd(),
+  "e2e",
+  "runs",
+  runId,
+  ".next",
+  "standalone",
+  ".next",
+);
+
 describe("next.config override", () => {
-  it("should have images optimization disabled", async () => {
-    const serverFiles = await fsExtra.readJson(
-      `${process.cwd()}/e2e/runs/${runId}/.next/standalone/.next/required-server-files.json`,
-    );
-    console.log(`serverFiles: ${JSON.stringify(serverFiles)}`);
+  it("should have images optimization disabled", async function () {
+    if (scenario.includes("with-empty-config")) {
+      this.skip();
+    }
+
+    const serverFiles = await fsExtra.readJson(`${compiledFilesPath}/required-server-files.json`);
     const config = serverFiles.config;
 
     // Verify that images.unoptimized is set to true
@@ -34,158 +45,66 @@ describe("next.config override", () => {
     );
   });
 
-  // it("should preserve user config settings", async () => {
-  //   // This test checks if the user's original config settings are preserved
-  //   // We'll check for the custom header that was set in the next.config
-  //   const response = await fetch(posix.join(host, "/"));
-  //   assert.ok(response.ok);
-
-  //   // Check for the custom header that was set in the next.config
-  //   if (scenario.includes("with-js-config")) {
-  //     assert.equal(response.headers.get("x-custom-header") ?? "", "js-config-value");
-  //   } else if (scenario.includes("with-ts-config")) {
-  //     assert.equal(response.headers.get("x-custom-header") ?? "", "ts-config-value");
-  //   } else if (scenario.includes("with-mjs-config")) {
-  //     assert.equal(response.headers.get("x-custom-header") ?? "", "mjs-config-value");
-  //   } else if (scenario.includes("with-complex-config")) {
-  //     assert.equal(response.headers.get("x-custom-header") ?? "", "complex-config-value");
-  //   }
-  // });
-
-  // it("should handle function-style config correctly", async () => {
-  //   // Only run this test for scenarios with function-style config
-  //   if (!scenario.includes("function-style")) {
-  //     this.skip();
-  //     return;
-  //   }
-
-  //   // Check for the custom header that indicates function-style config was processed correctly
-  //   const response = await fetch(posix.join(host, "/"));
-  //   assert.ok(response.ok);
-  //   assert.equal(response.headers.get("x-config-type") ?? "", "function");
-  // });
-
-  // it("should handle object-style config correctly", async () => {
-  //   // Only run this test for scenarios with object-style config
-  //   if (
-  //     !scenario.includes("object-style") &&
-  //     !scenario.includes("with-complex-config") &&
-  //     !scenario.includes("with-empty-config")
-  //   ) {
-  //     this.skip();
-  //     return;
-  //   }
-
-  //   // Check for the custom header that indicates object-style config was processed correctly
-  //   const response = await fetch(posix.join(host, "/"));
-  //   assert.ok(response.ok);
-
-  //   // Empty config doesn't set this header
-  //   if (!scenario.includes("with-empty-config")) {
-  //     assert.equal(response.headers.get("x-config-type") ?? "", "object");
-  //   }
-  // });
-
-  // it("should handle empty config correctly", async () => {
-  //   // Only run this test for the empty config scenario
-  //   if (!scenario.includes("with-empty-config")) {
-  //     this.skip();
-  //     return;
-  //   }
-
-  //   // Just check that the page loads successfully
-  //   const response = await fetch(posix.join(host, "/"));
-  //   assert.ok(response.ok);
-  // });
-
-  // it("should verify original config file was preserved", async () => {
-  //   // This test verifies that the original config file was preserved
-  //   // We'll check the file system to make sure the original config file exists
-  //   let originalConfigExists = false;
-
-  //   if (scenario.includes("with-js-config")) {
-  //     originalConfigExists = await fsExtra.pathExists("next.config.original.js");
-  //   } else if (scenario.includes("with-ts-config")) {
-  //     originalConfigExists = await fsExtra.pathExists("next.config.original.ts");
-  //   } else if (scenario.includes("with-mjs-config")) {
-  //     originalConfigExists = await fsExtra.pathExists("next.config.original.mjs");
-  //   } else if (
-  //     scenario.includes("with-empty-config") ||
-  //     scenario.includes("with-complex-config") ||
-  //     scenario.includes("with-error-handling")
-  //   ) {
-  //     originalConfigExists = await fsExtra.pathExists("next.config.original.js");
-  //   }
-
-  //   assert.ok(originalConfigExists, "Original config file should be preserved");
-  // });
-
-  // it("should handle error gracefully when config file has syntax errors", async () => {
-  //   // Only run this test for the error handling scenario
-  //   if (!scenario.includes("with-error-handling")) {
-  //     this.skip();
-  //     return;
-  //   }
-
-  //   // The build should have succeeded despite the invalid config file
-  //   // because we started with a valid config
-  //   const response = await fetch(posix.join(host, "/"));
-  //   assert.ok(response.ok);
-
-  //   // Check if the invalid config file exists
-  //   const invalidConfigExists = await fsExtra.pathExists("next.config.invalid.js");
-  //   assert.ok(invalidConfigExists, "Invalid config file should exist");
-  // });
-
-  // it("should verify the generated config file has the correct format", async () => {
-  //   // Skip for error handling scenario
-  //   if (scenario.includes("with-error-handling")) {
-  //     this.skip();
-  //     return;
-  //   }
-
-  //   let configPath = "";
-
-  //   if (scenario.includes("with-js-config")) {
-  //     configPath = "next.config.js";
-  //   } else if (scenario.includes("with-ts-config")) {
-  //     configPath = "next.config.ts";
-  //   } else if (scenario.includes("with-mjs-config")) {
-  //     configPath = "next.config.mjs";
-  //   } else if (scenario.includes("with-empty-config") || scenario.includes("with-complex-config")) {
-  //     configPath = "next.config.js";
-  //   }
-
-  //   // Check if the generated config file exists
-  //   const configExists = await fsExtra.pathExists(configPath);
-  //   assert.ok(configExists, "Generated config file should exist");
-
-  //   // Read the config file content
-  //   const configContent = await fsExtra.readFile(configPath, "utf-8");
-
-  //   // Verify that the config file contains the unoptimized: true setting
-  //   assert.ok(configContent.includes("unoptimized: true"), "Config should have unoptimized: true");
-
-  //   // Verify that the config file imports the original config
-  //   if (
-  //     scenario.includes("with-js-config") ||
-  //     scenario.includes("with-empty-config") ||
-  //     scenario.includes("with-complex-config")
-  //   ) {
-  //     assert.ok(
-  //       configContent.includes("require('./next.config.original.js')"),
-  //       "Config should import the original JS config",
-  //     );
-  //   } else if (scenario.includes("with-ts-config")) {
-  //     assert.ok(
-  //       configContent.includes("import originalConfig from './next.config.original'"),
-  //       "Config should import the original TS config",
-  //     );
-  //   } else if (scenario.includes("with-mjs-config")) {
-  //     assert.ok(
-  //       configContent.includes("import originalConfig from './next.config.original.mjs'"),
-  //       "Config should import the original MJS config",
-  //     );
-  //   }
-  // });
+  it("should preserve other user set next configs", async function () {
+    if (scenario.includes("with-empty-config")) {
+      this.skip();
+    }
+
+    // This test checks if the user's original config settings are preserved
+    // We'll check for the custom header that was set in the next.config
+    const response = await fetch(posix.join(host, "/"));
+
+    // Log all headers individually for debugging
+    console.log("Response headers:");
+    response.headers.forEach((value, key) => {
+      console.log(`  ${key}: ${value}`);
+    });
+
+    assert.ok(response.ok);
+
+    // Check for the custom header that was set in the next.config
+    const customHeader = response.headers.get("x-custom-header") ?? "";
+    const validValues = [
+      "js-config-value",
+      "ts-config-value",
+      "mjs-config-value",
+      "complex-config-value",
+    ];
+    assert.ok(
+      validValues.includes(customHeader),
+      `Expected header to be one of ${validValues.join(", ")} but got "${customHeader}"`,
+    );
+  });
+
+  it("should handle function-style config correctly", async function () {
+    // Only run this test for scenarios with function-style config
+    if (!scenario.includes("function-style")) {
+      this.skip();
+    }
+
+    // Check for the custom header that indicates function-style config was processed correctly
+    const response = await fetch(posix.join(host, "/"));
+    assert.ok(response.ok);
+    assert.equal(response.headers.get("x-config-type") ?? "", "function");
+  });
+
+  it("should handle object-style config correctly", async function () {
+    // Only run this test for scenarios with object-style config
+    if (
+      !scenario.includes("object-style") &&
+      !scenario.includes("with-complex-config") &&
+      !scenario.includes("with-empty-config")
+    ) {
+      this.skip();
+    }
+
+    // Check for the custom header that indicates object-style config was processed correctly
+    const response = await fetch(posix.join(host, "/"));
+    assert.ok(response.ok);
+
+    // Empty config doesn't set this header
+    if (!scenario.includes("with-empty-config")) {
+      assert.equal(response.headers.get("x-config-type") ?? "", "object");
+    }
+  });
 });
diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index 2dde98c9..2319e745 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -6,7 +6,7 @@ import { parse as parseYaml } from "yaml";
 import { spawn } from "child_process";
 import fsExtra from "fs-extra";
 
-const { readFileSync, mkdirp, rmdir } = fsExtra;
+const { readFileSync, mkdirp, rm } = fsExtra;
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
@@ -19,6 +19,11 @@ interface Scenario {
   tests?: string[]; // List of test files to run
 }
 
+// Load test data for config override
+const configOverrideTestScenarios = parseYaml(
+  readFileSync(join(__dirname, "config-override-test-cases.yaml"), "utf8"),
+).tests;
+
 const scenarios: Scenario[] = [
   // {
   //   name: "basic",
@@ -47,133 +52,30 @@ const scenarios: Scenario[] = [
   //   },
   //   tests: ["middleware.spec.ts"], // Only run middleware-specific tests
   // },
-  // New scenarios for testing Next.js config override behavior
-  {
-    name: "with-js-config-object-style",
-    setup: async (cwd: string) => {
-      // Create a next.config.js file with object-style config
-      const configContent = `
-        /** @type {import('next').NextConfig} */
-        const nextConfig = {
-          reactStrictMode: true,
-          async headers() {
-            return [
-              {
-                source: '/:path*',
-                headers: [
-                  {
-                    key: 'x-custom-header',
-                    value: 'js-config-value',
-                  },
-                  {
-                    key: 'x-config-type',
-                    value: 'object',
-                  },
-                ],
-              },
-            ];
-          },
-        };
-        
-        module.exports = nextConfig;
-      `;
-
-      await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
-      console.log(`Created next.config.js file with object-style config`);
-    },
-    tests: ["config-override.spec.ts"],
-  },
-  // {
-  //   name: "with-js-config-object-style",
-  //   setup: async (cwd: string) => {
-  //     // Create a next.config.js file with object-style config
-  //     const configContent = `
-  //       /** @type {import('next').NextConfig} */
-  //       const nextConfig = {
-  //         reactStrictMode: true,
-  //         async headers() {
-  //           return [
-  //             {
-  //               source: '/:path*',
-  //               headers: [
-  //                 {
-  //                   key: 'x-custom-header',
-  //                   value: 'js-config-value',
-  //                 },
-  //                 {
-  //                   key: 'x-config-type',
-  //                   value: 'object',
-  //                 },
-  //               ],
-  //             },
-  //           ];
-  //         },
-  //         // This should be overridden by the adapter
-  //         images: {
-  //           unoptimized: false,
-  //           domains: ['example.com'],
-  //         },
-  //       };
-
-  //       module.exports = nextConfig;
-  //     `;
-
-  //     await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
-  //     console.log(`Created next.config.js file with object-style config`);
-  //   },
-  //   tests: ["config-override.spec.ts"],
-  // },
-  // {
-  //   name: "with-js-config-function-style",
-  //   setup: async (cwd: string) => {
-  //     // Create a next.config.js file with function-style config
-  //     const configContent = `
-  //       /** @type {import('next').NextConfig} */
-  //       const nextConfig = (phase, { defaultConfig }) => {
-  //         return {
-  //           reactStrictMode: true,
-  //           async headers() {
-  //             return [
-  //               {
-  //                 source: '/:path*',
-  //                 headers: [
-  //                   {
-  //                     key: 'x-custom-header',
-  //                     value: 'js-config-value',
-  //                   },
-  //                   {
-  //                     key: 'x-config-type',
-  //                     value: 'function',
-  //                   },
-  //                 ],
-  //               },
-  //             ];
-  //           },
-  //           // This should be overridden by the adapter
-  //           images: {
-  //             unoptimized: false,
-  //             domains: ['example.com'],
-  //           },
-  //         };
-  //       };
-
-  //       module.exports = nextConfig;
-  //     `;
-
-  //     await fsExtra.writeFile(join(cwd, "next.config.js"), configContent);
-  //     console.log(`Created next.config.js file with function-style config`);
-  //   },
-  //   tests: ["config-override.spec.ts"],
-  // },
+  ...configOverrideTestScenarios.map(
+    (scenario: { name: string; config: string; file: string }) => ({
+      name: scenario.name,
+      setup: async (cwd: string) => {
+        const configContent = scenario.config;
+        await fsExtra.writeFile(join(cwd, scenario.file), configContent);
+        console.log(`Created ${scenario.file} file with ${scenario.name} config`);
+      },
+      tests: ["config-override.spec.ts"],
+    }),
+  ),
 ];
 
 const errors: any[] = [];
 
-await rmdir(join(__dirname, "runs"), { recursive: true }).catch(() => undefined);
+await rm(join(__dirname, "runs"), { recursive: true }).catch(() => undefined);
 
 // Run each scenario
 for (const scenario of scenarios) {
-  console.log(`\n\nRunning scenario: ${scenario.name}`);
+  console.log(
+    `\n\n${"=".repeat(80)}\n${" ".repeat(
+      5,
+    )}RUNNING SCENARIO: ${scenario.name.toUpperCase()}${" ".repeat(5)}\n${"=".repeat(80)}`,
+  );
 
   const runId = `${scenario.name}-${Math.random().toString().split(".")[1]}`;
   const cwd = join(__dirname, "runs", runId);

From 8b729203aa68aa572c1613c80374fa418aa156e0 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 13:12:20 -0500
Subject: [PATCH 09/28] support async next configs

---
 .../e2e/config-override-test-cases.yaml       | 210 +++++++++---------
 .../e2e/config-override.spec.ts               |   6 -
 .../adapter-nextjs/e2e/run-local.ts           |  54 ++---
 .../adapter-nextjs/src/overrides.spec.ts      |   6 +-
 .../adapter-nextjs/src/overrides.ts           |   4 +-
 5 files changed, 137 insertions(+), 143 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
index c9ff6a7f..94151b31 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
@@ -1,58 +1,58 @@
 tests:
-  # - name: with-js-config-object-style
-  #   config: |
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = {
-  #       reactStrictMode: true,
-  #       async headers() {
-  #         return [
-  #           {
-  #             source: '/:path*',
-  #             headers: [
-  #               {
-  #                 key: 'x-custom-header',
-  #                 value: 'js-config-value',
-  #               },
-  #               {
-  #                 key: 'x-config-type',
-  #                 value: 'object',
-  #               },
-  #             ],
-  #           },
-  #         ];
-  #       },
-  #     };
+  - name: with-js-config-object-style
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        reactStrictMode: true,
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'js-config-value',
+                },
+                {
+                  key: 'x-config-type',
+                  value: 'object',
+                },
+              ],
+            },
+          ];
+        },
+      };
 
-  #     module.exports = nextConfig;
-  #   file: next.config.js
-  # - name: with-js-config-function-style
-  #   config: |
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = (phase, { defaultConfig }) => {
-  #       return {
-  #         reactStrictMode: true,
-  #         async headers() {
-  #           return [
-  #             {
-  #               source: '/:path*',
-  #               headers: [
-  #                 {
-  #                   key: 'x-custom-header',
-  #                   value: 'js-config-value',
-  #                 },
-  #                 {
-  #                   key: 'x-config-type',
-  #                   value: 'function',
-  #                 },
-  #               ],
-  #             },
-  #           ];
-  #         }
-  #       };
-  #     };
+      module.exports = nextConfig;
+    file: next.config.js
+  - name: with-js-config-function-style
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = (phase, { defaultConfig }) => {
+        return {
+          reactStrictMode: true,
+          async headers() {
+            return [
+              {
+                source: '/:path*',
+                headers: [
+                  {
+                    key: 'x-custom-header',
+                    value: 'js-config-value',
+                  },
+                  {
+                    key: 'x-config-type',
+                    value: 'function',
+                  },
+                ],
+              },
+            ];
+          }
+        };
+      };
 
-  #     module.exports = nextConfig;
-  #   file: next.config.js
+      module.exports = nextConfig;
+    file: next.config.js
   - name: with-js-async-function
     config: |
       // @ts-check
@@ -83,62 +83,62 @@ tests:
         return nextConfig
       }
     file: next.config.js
-  # - name: with-ts-config
-  #   config: |
-  #     import type { NextConfig } from 'next'
+  - name: with-ts-config
+    config: |
+      import type { NextConfig } from 'next'
 
-  #     const nextConfig: NextConfig = {
-  #       async headers() {
-  #         return [
-  #           {
-  #             source: '/:path*',
-  #             headers: [
-  #               {
-  #                 key: 'x-custom-header',
-  #                 value: 'ts-config-value',
-  #               }
-  #             ],
-  #           },
-  #         ];
-  #       }
-  #     }
+      const nextConfig: NextConfig = {
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'ts-config-value',
+                }
+              ],
+            },
+          ];
+        }
+      }
 
-  #     export default nextConfig
-  #   file: next.config.ts
-  # - name: with-ecmascript-modules
-  #   config: |
-  #     // @ts-check
+      export default nextConfig
+    file: next.config.ts
+  - name: with-ecmascript-modules
+    config: |
+      // @ts-check
 
-  #     /**
-  #     * @type {import('next').NextConfig}
-  #     */
-  #     const nextConfig = {
-  #       /* config options here */
-  #       async headers() {
-  #         return [
-  #           {
-  #             source: '/:path*',
-  #             headers: [
-  #               {
-  #                 key: 'x-custom-header',
-  #                 value: 'mjs-config-value',
-  #               },
-  #             ],
-  #           },
-  #         ];
-  #       }
-  #     }
+      /**
+      * @type {import('next').NextConfig}
+      */
+      const nextConfig = {
+        /* config options here */
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'mjs-config-value',
+                },
+              ],
+            },
+          ];
+        }
+      }
 
-  #     export default nextConfig
-  #   file: next.config.mjs
-  # - name: with-empty-config
-  #   config: |
-  #     // @ts-check
+      export default nextConfig
+    file: next.config.mjs
+  - name: with-empty-config
+    config: |
+      // @ts-check
 
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = {
-  #       /* config options here */
-  #     }
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        /* config options here */
+      }
 
-  #     module.exports = nextConfig
-  #   file: next.config.js
+      module.exports = nextConfig
+    file: next.config.js
diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
index b8fabeee..6dcc73c9 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
@@ -54,12 +54,6 @@ describe("next.config override", () => {
     // We'll check for the custom header that was set in the next.config
     const response = await fetch(posix.join(host, "/"));
 
-    // Log all headers individually for debugging
-    console.log("Response headers:");
-    response.headers.forEach((value, key) => {
-      console.log(`  ${key}: ${value}`);
-    });
-
     assert.ok(response.ok);
 
     // Check for the custom header that was set in the next.config
diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index 2319e745..6885c15d 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -25,33 +25,33 @@ const configOverrideTestScenarios = parseYaml(
 ).tests;
 
 const scenarios: Scenario[] = [
-  // {
-  //   name: "basic",
-  //   // No setup needed for basic scenario
-  //   tests: ["app.spec.ts"],
-  // },
-  // {
-  //   name: "with-middleware",
-  //   setup: async (cwd: string) => {
-  //     // Create a middleware.ts file
-  //     const middlewareContent = `
-  //       import type { NextRequest } from 'next/server'
-
-  //       export function middleware(request: NextRequest) {
-  //         // This is a simple middleware that doesn't modify the request
-  //         console.log('Middleware executed', request.nextUrl.pathname);
-  //       }
-
-  //       export const config = {
-  //         matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
-  //       };
-  //     `;
-
-  //     await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
-  //     console.log(`Created middleware.ts file`);
-  //   },
-  //   tests: ["middleware.spec.ts"], // Only run middleware-specific tests
-  // },
+  {
+    name: "basic",
+    // No setup needed for basic scenario
+    tests: ["app.spec.ts"],
+  },
+  {
+    name: "with-middleware",
+    setup: async (cwd: string) => {
+      // Create a middleware.ts file
+      const middlewareContent = `
+        import type { NextRequest } from 'next/server'
+
+        export function middleware(request: NextRequest) {
+          // This is a simple middleware that doesn't modify the request
+          console.log('Middleware executed', request.nextUrl.pathname);
+        }
+
+        export const config = {
+          matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
+        };
+      `;
+
+      await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
+      console.log(`Created middleware.ts file`);
+    },
+    tests: ["middleware.spec.ts"], // Only run middleware-specific tests
+  },
   ...configOverrideTestScenarios.map(
     (scenario: { name: string; config: string; file: string }) => ({
       name: scenario.name,
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index 3efa78c3..326d1f2b 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -179,12 +179,12 @@ describe("next config overrides", () => {
   });
 
   const config = typeof originalConfig === 'function' 
-    ? (...args) => {
-        const resolvedConfig = originalConfig(...args);
+    ? async (...args) => {
+        const resolvedConfig = await originalConfig(...args);
         return fahOptimizedConfig(resolvedConfig);
       }
     : fahOptimizedConfig(originalConfig);
-    `;
+  `;
 
   beforeEach(() => {
     tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-overrides"));
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index a663bef4..f5a748ec 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -69,8 +69,8 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
   });
 
   const config = typeof originalConfig === 'function' 
-    ? (...args) => {
-        const resolvedConfig = originalConfig(...args);
+    ? async (...args) => {
+        const resolvedConfig = await originalConfig(...args);
         return fahOptimizedConfig(resolvedConfig);
       }
     : fahOptimizedConfig(originalConfig);

From 141d46eb9a371f67c7f238b6852e5a81ad5ca93c Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 13:25:32 -0500
Subject: [PATCH 10/28] debug

---
 .../e2e/config-override-test-cases.yaml       | 228 +++++++++---------
 .../e2e/config-override.spec.ts               |  13 +-
 .../adapter-nextjs/e2e/run-local.ts           |  54 ++---
 3 files changed, 143 insertions(+), 152 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
index 94151b31..e3d41a34 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
@@ -1,88 +1,88 @@
 tests:
-  - name: with-js-config-object-style
-    config: |
-      /** @type {import('next').NextConfig} */
-      const nextConfig = {
-        reactStrictMode: true,
-        async headers() {
-          return [
-            {
-              source: '/:path*',
-              headers: [
-                {
-                  key: 'x-custom-header',
-                  value: 'js-config-value',
-                },
-                {
-                  key: 'x-config-type',
-                  value: 'object',
-                },
-              ],
-            },
-          ];
-        },
-      };
+  # - name: with-js-config-object-style
+  #   config: |
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = {
+  #       reactStrictMode: true,
+  #       async headers() {
+  #         return [
+  #           {
+  #             source: '/:path*',
+  #             headers: [
+  #               {
+  #                 key: 'x-custom-header',
+  #                 value: 'js-config-value',
+  #               },
+  #               {
+  #                 key: 'x-config-type',
+  #                 value: 'object',
+  #               },
+  #             ],
+  #           },
+  #         ];
+  #       },
+  #     };
 
-      module.exports = nextConfig;
-    file: next.config.js
-  - name: with-js-config-function-style
-    config: |
-      /** @type {import('next').NextConfig} */
-      const nextConfig = (phase, { defaultConfig }) => {
-        return {
-          reactStrictMode: true,
-          async headers() {
-            return [
-              {
-                source: '/:path*',
-                headers: [
-                  {
-                    key: 'x-custom-header',
-                    value: 'js-config-value',
-                  },
-                  {
-                    key: 'x-config-type',
-                    value: 'function',
-                  },
-                ],
-              },
-            ];
-          }
-        };
-      };
+  #     module.exports = nextConfig;
+  #   file: next.config.js
+  # - name: with-js-config-function-style
+  #   config: |
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = (phase, { defaultConfig }) => {
+  #       return {
+  #         reactStrictMode: true,
+  #         async headers() {
+  #           return [
+  #             {
+  #               source: '/:path*',
+  #               headers: [
+  #                 {
+  #                   key: 'x-custom-header',
+  #                   value: 'js-config-value',
+  #                 },
+  #                 {
+  #                   key: 'x-config-type',
+  #                   value: 'function',
+  #                 },
+  #               ],
+  #             },
+  #           ];
+  #         }
+  #       };
+  #     };
 
-      module.exports = nextConfig;
-    file: next.config.js
-  - name: with-js-async-function
-    config: |
-      // @ts-check
+  #     module.exports = nextConfig;
+  #   file: next.config.js
+  # - name: with-js-async-function
+  #   config: |
+  #     // @ts-check
 
-      module.exports = async (phase, { defaultConfig }) => {
-        /**
-        * @type {import('next').NextConfig}
-        */
-        const nextConfig = {
-          async headers() {
-            return [
-              {
-                source: '/:path*',
-                headers: [
-                  {
-                    key: 'x-custom-header',
-                    value: 'js-config-value',
-                  },
-                  {
-                    key: 'x-config-type',
-                    value: 'function',
-                  },
-                ],
-              },
-            ];
-          }
-        }
-        return nextConfig
-      }
-    file: next.config.js
+  #     module.exports = async (phase, { defaultConfig }) => {
+  #       /**
+  #       * @type {import('next').NextConfig}
+  #       */
+  #       const nextConfig = {
+  #         async headers() {
+  #           return [
+  #             {
+  #               source: '/:path*',
+  #               headers: [
+  #                 {
+  #                   key: 'x-custom-header',
+  #                   value: 'js-config-value',
+  #                 },
+  #                 {
+  #                   key: 'x-config-type',
+  #                   value: 'function',
+  #                 },
+  #               ],
+  #             },
+  #           ];
+  #         }
+  #       }
+  #       return nextConfig
+  #     }
+  #   file: next.config.js
   - name: with-ts-config
     config: |
       import type { NextConfig } from 'next'
@@ -105,40 +105,40 @@ tests:
 
       export default nextConfig
     file: next.config.ts
-  - name: with-ecmascript-modules
-    config: |
-      // @ts-check
+  # - name: with-ecmascript-modules
+  #   config: |
+  #     // @ts-check
 
-      /**
-      * @type {import('next').NextConfig}
-      */
-      const nextConfig = {
-        /* config options here */
-        async headers() {
-          return [
-            {
-              source: '/:path*',
-              headers: [
-                {
-                  key: 'x-custom-header',
-                  value: 'mjs-config-value',
-                },
-              ],
-            },
-          ];
-        }
-      }
+  #     /**
+  #     * @type {import('next').NextConfig}
+  #     */
+  #     const nextConfig = {
+  #       /* config options here */
+  #       async headers() {
+  #         return [
+  #           {
+  #             source: '/:path*',
+  #             headers: [
+  #               {
+  #                 key: 'x-custom-header',
+  #                 value: 'mjs-config-value',
+  #               },
+  #             ],
+  #           },
+  #         ];
+  #       }
+  #     }
 
-      export default nextConfig
-    file: next.config.mjs
-  - name: with-empty-config
-    config: |
-      // @ts-check
+  #     export default nextConfig
+  #   file: next.config.mjs
+  # - name: with-empty-config
+  #   config: |
+  #     // @ts-check
 
-      /** @type {import('next').NextConfig} */
-      const nextConfig = {
-        /* config options here */
-      }
+  #     /** @type {import('next').NextConfig} */
+  #     const nextConfig = {
+  #       /* config options here */
+  #     }
 
-      module.exports = nextConfig
-    file: next.config.js
+  #     module.exports = nextConfig
+  #   file: next.config.js
diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
index 6dcc73c9..55c0607a 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
@@ -58,12 +58,7 @@ describe("next.config override", () => {
 
     // Check for the custom header that was set in the next.config
     const customHeader = response.headers.get("x-custom-header") ?? "";
-    const validValues = [
-      "js-config-value",
-      "ts-config-value",
-      "mjs-config-value",
-      "complex-config-value",
-    ];
+    const validValues = ["js-config-value", "ts-config-value", "mjs-config-value"];
     assert.ok(
       validValues.includes(customHeader),
       `Expected header to be one of ${validValues.join(", ")} but got "${customHeader}"`,
@@ -84,11 +79,7 @@ describe("next.config override", () => {
 
   it("should handle object-style config correctly", async function () {
     // Only run this test for scenarios with object-style config
-    if (
-      !scenario.includes("object-style") &&
-      !scenario.includes("with-complex-config") &&
-      !scenario.includes("with-empty-config")
-    ) {
+    if (!scenario.includes("object-style") && !scenario.includes("with-empty-config")) {
       this.skip();
     }
 
diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index 6885c15d..2319e745 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -25,33 +25,33 @@ const configOverrideTestScenarios = parseYaml(
 ).tests;
 
 const scenarios: Scenario[] = [
-  {
-    name: "basic",
-    // No setup needed for basic scenario
-    tests: ["app.spec.ts"],
-  },
-  {
-    name: "with-middleware",
-    setup: async (cwd: string) => {
-      // Create a middleware.ts file
-      const middlewareContent = `
-        import type { NextRequest } from 'next/server'
-
-        export function middleware(request: NextRequest) {
-          // This is a simple middleware that doesn't modify the request
-          console.log('Middleware executed', request.nextUrl.pathname);
-        }
-
-        export const config = {
-          matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
-        };
-      `;
-
-      await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
-      console.log(`Created middleware.ts file`);
-    },
-    tests: ["middleware.spec.ts"], // Only run middleware-specific tests
-  },
+  // {
+  //   name: "basic",
+  //   // No setup needed for basic scenario
+  //   tests: ["app.spec.ts"],
+  // },
+  // {
+  //   name: "with-middleware",
+  //   setup: async (cwd: string) => {
+  //     // Create a middleware.ts file
+  //     const middlewareContent = `
+  //       import type { NextRequest } from 'next/server'
+
+  //       export function middleware(request: NextRequest) {
+  //         // This is a simple middleware that doesn't modify the request
+  //         console.log('Middleware executed', request.nextUrl.pathname);
+  //       }
+
+  //       export const config = {
+  //         matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
+  //       };
+  //     `;
+
+  //     await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
+  //     console.log(`Created middleware.ts file`);
+  //   },
+  //   tests: ["middleware.spec.ts"], // Only run middleware-specific tests
+  // },
   ...configOverrideTestScenarios.map(
     (scenario: { name: string; config: string; file: string }) => ({
       name: scenario.name,

From 1e98f4ff9f1f8993a21d5f73f3ce22b8bf310b83 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 13:43:05 -0500
Subject: [PATCH 11/28] fix up e2e tests

---
 package-lock.json                             | 103 ++++++++
 .../e2e/config-override-test-cases.yaml       | 228 +++++++++---------
 .../adapter-nextjs/e2e/run-local.ts           |  63 ++---
 .../@apphosting/adapter-nextjs/package.json   |   1 +
 4 files changed, 254 insertions(+), 141 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 18c0844c..32014a55 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19774,6 +19774,12 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
+    "node_modules/package-json-from-dist": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/package-json-from-dist/-/package-json-from-dist-1.0.1.tgz",
+      "integrity": "sha512-UEZIS3/by4OC8vL3P2dTXRETpebLI2NiI5vIrjaD/5UtrkFX/tNbwjTSRAGC/+7CAo2pIcBaRgWmcBBHcsaCIw==",
+      "dev": true
+    },
     "node_modules/pacote": {
       "version": "15.2.0",
       "resolved": "https://registry.npmjs.org/pacote/-/pacote-15.2.0.tgz",
@@ -25633,6 +25639,7 @@
         "@types/fs-extra": "*",
         "@types/mocha": "*",
         "@types/tmp": "*",
+        "glob": "^11.0.1",
         "mocha": "*",
         "next": "~14.0.0",
         "semver": "*",
@@ -25651,6 +25658,102 @@
         }
       }
     },
+    "packages/@apphosting/adapter-nextjs/node_modules/brace-expansion": {
+      "version": "2.0.1",
+      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-2.0.1.tgz",
+      "integrity": "sha512-XnAIvQ8eM+kC6aULx6wuQiwVsnzsi9d3WxzV3FpWTGA19F621kwdbsAcFKXgKUHZWsy+mY6iL1sHTxWEFCytDA==",
+      "dev": true,
+      "dependencies": {
+        "balanced-match": "^1.0.0"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/glob": {
+      "version": "11.0.1",
+      "resolved": "https://registry.npmjs.org/glob/-/glob-11.0.1.tgz",
+      "integrity": "sha512-zrQDm8XPnYEKawJScsnM0QzobJxlT/kHOOlRTio8IH/GrmxRE5fjllkzdaHclIuNjUQTJYH2xHNIGfdpJkDJUw==",
+      "dev": true,
+      "dependencies": {
+        "foreground-child": "^3.1.0",
+        "jackspeak": "^4.0.1",
+        "minimatch": "^10.0.0",
+        "minipass": "^7.1.2",
+        "package-json-from-dist": "^1.0.0",
+        "path-scurry": "^2.0.0"
+      },
+      "bin": {
+        "glob": "dist/esm/bin.mjs"
+      },
+      "engines": {
+        "node": "20 || >=22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/jackspeak": {
+      "version": "4.1.0",
+      "resolved": "https://registry.npmjs.org/jackspeak/-/jackspeak-4.1.0.tgz",
+      "integrity": "sha512-9DDdhb5j6cpeitCbvLO7n7J4IxnbM6hoF6O1g4HQ5TfhvvKN8ywDM7668ZhMHRqVmxqhps/F6syWK2KcPxYlkw==",
+      "dev": true,
+      "dependencies": {
+        "@isaacs/cliui": "^8.0.2"
+      },
+      "engines": {
+        "node": "20 || >=22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/lru-cache": {
+      "version": "11.0.2",
+      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-11.0.2.tgz",
+      "integrity": "sha512-123qHRfJBmo2jXDbo/a5YOQrJoHF/GNQTLzQ5+IdK5pWpceK17yRc6ozlWd25FxvGKQbIUs91fDFkXmDHTKcyA==",
+      "dev": true,
+      "engines": {
+        "node": "20 || >=22"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/minimatch": {
+      "version": "10.0.1",
+      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-10.0.1.tgz",
+      "integrity": "sha512-ethXTt3SGGR+95gudmqJ1eNhRO7eGEGIgYA9vnPatK4/etz2MEVDno5GMCibdMTuBMyElzIlgxMna3K94XDIDQ==",
+      "dev": true,
+      "dependencies": {
+        "brace-expansion": "^2.0.1"
+      },
+      "engines": {
+        "node": "20 || >=22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/minipass": {
+      "version": "7.1.2",
+      "resolved": "https://registry.npmjs.org/minipass/-/minipass-7.1.2.tgz",
+      "integrity": "sha512-qOOzS1cBTWYF4BH8fVePDBOO9iptMnGUEZwNc/cMWnTV2nVLZ7VoNWEPHkYczZA0pdoA7dl6e7FL659nX9S2aw==",
+      "dev": true,
+      "engines": {
+        "node": ">=16 || 14 >=14.17"
+      }
+    },
+    "packages/@apphosting/adapter-nextjs/node_modules/path-scurry": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/path-scurry/-/path-scurry-2.0.0.tgz",
+      "integrity": "sha512-ypGJsmGtdXUOeM5u93TyeIEfEhM6s+ljAhrk5vAvSx8uyY/02OvrZnA0YNGUrPXfpJMgI1ODd3nwz8Npx4O4cg==",
+      "dev": true,
+      "dependencies": {
+        "lru-cache": "^11.0.0",
+        "minipass": "^7.1.2"
+      },
+      "engines": {
+        "node": "20 || >=22"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/isaacs"
+      }
+    },
     "packages/@apphosting/build": {
       "version": "0.1.0",
       "license": "Apache-2.0",
diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
index e3d41a34..94151b31 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
@@ -1,88 +1,88 @@
 tests:
-  # - name: with-js-config-object-style
-  #   config: |
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = {
-  #       reactStrictMode: true,
-  #       async headers() {
-  #         return [
-  #           {
-  #             source: '/:path*',
-  #             headers: [
-  #               {
-  #                 key: 'x-custom-header',
-  #                 value: 'js-config-value',
-  #               },
-  #               {
-  #                 key: 'x-config-type',
-  #                 value: 'object',
-  #               },
-  #             ],
-  #           },
-  #         ];
-  #       },
-  #     };
+  - name: with-js-config-object-style
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        reactStrictMode: true,
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'js-config-value',
+                },
+                {
+                  key: 'x-config-type',
+                  value: 'object',
+                },
+              ],
+            },
+          ];
+        },
+      };
 
-  #     module.exports = nextConfig;
-  #   file: next.config.js
-  # - name: with-js-config-function-style
-  #   config: |
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = (phase, { defaultConfig }) => {
-  #       return {
-  #         reactStrictMode: true,
-  #         async headers() {
-  #           return [
-  #             {
-  #               source: '/:path*',
-  #               headers: [
-  #                 {
-  #                   key: 'x-custom-header',
-  #                   value: 'js-config-value',
-  #                 },
-  #                 {
-  #                   key: 'x-config-type',
-  #                   value: 'function',
-  #                 },
-  #               ],
-  #             },
-  #           ];
-  #         }
-  #       };
-  #     };
+      module.exports = nextConfig;
+    file: next.config.js
+  - name: with-js-config-function-style
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = (phase, { defaultConfig }) => {
+        return {
+          reactStrictMode: true,
+          async headers() {
+            return [
+              {
+                source: '/:path*',
+                headers: [
+                  {
+                    key: 'x-custom-header',
+                    value: 'js-config-value',
+                  },
+                  {
+                    key: 'x-config-type',
+                    value: 'function',
+                  },
+                ],
+              },
+            ];
+          }
+        };
+      };
 
-  #     module.exports = nextConfig;
-  #   file: next.config.js
-  # - name: with-js-async-function
-  #   config: |
-  #     // @ts-check
+      module.exports = nextConfig;
+    file: next.config.js
+  - name: with-js-async-function
+    config: |
+      // @ts-check
 
-  #     module.exports = async (phase, { defaultConfig }) => {
-  #       /**
-  #       * @type {import('next').NextConfig}
-  #       */
-  #       const nextConfig = {
-  #         async headers() {
-  #           return [
-  #             {
-  #               source: '/:path*',
-  #               headers: [
-  #                 {
-  #                   key: 'x-custom-header',
-  #                   value: 'js-config-value',
-  #                 },
-  #                 {
-  #                   key: 'x-config-type',
-  #                   value: 'function',
-  #                 },
-  #               ],
-  #             },
-  #           ];
-  #         }
-  #       }
-  #       return nextConfig
-  #     }
-  #   file: next.config.js
+      module.exports = async (phase, { defaultConfig }) => {
+        /**
+        * @type {import('next').NextConfig}
+        */
+        const nextConfig = {
+          async headers() {
+            return [
+              {
+                source: '/:path*',
+                headers: [
+                  {
+                    key: 'x-custom-header',
+                    value: 'js-config-value',
+                  },
+                  {
+                    key: 'x-config-type',
+                    value: 'function',
+                  },
+                ],
+              },
+            ];
+          }
+        }
+        return nextConfig
+      }
+    file: next.config.js
   - name: with-ts-config
     config: |
       import type { NextConfig } from 'next'
@@ -105,40 +105,40 @@ tests:
 
       export default nextConfig
     file: next.config.ts
-  # - name: with-ecmascript-modules
-  #   config: |
-  #     // @ts-check
+  - name: with-ecmascript-modules
+    config: |
+      // @ts-check
 
-  #     /**
-  #     * @type {import('next').NextConfig}
-  #     */
-  #     const nextConfig = {
-  #       /* config options here */
-  #       async headers() {
-  #         return [
-  #           {
-  #             source: '/:path*',
-  #             headers: [
-  #               {
-  #                 key: 'x-custom-header',
-  #                 value: 'mjs-config-value',
-  #               },
-  #             ],
-  #           },
-  #         ];
-  #       }
-  #     }
+      /**
+      * @type {import('next').NextConfig}
+      */
+      const nextConfig = {
+        /* config options here */
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'mjs-config-value',
+                },
+              ],
+            },
+          ];
+        }
+      }
 
-  #     export default nextConfig
-  #   file: next.config.mjs
-  # - name: with-empty-config
-  #   config: |
-  #     // @ts-check
+      export default nextConfig
+    file: next.config.mjs
+  - name: with-empty-config
+    config: |
+      // @ts-check
 
-  #     /** @type {import('next').NextConfig} */
-  #     const nextConfig = {
-  #       /* config options here */
-  #     }
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        /* config options here */
+      }
 
-  #     module.exports = nextConfig
-  #   file: next.config.js
+      module.exports = nextConfig
+    file: next.config.js
diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index 2319e745..d97f30ee 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -5,6 +5,7 @@ import { fileURLToPath } from "url";
 import { parse as parseYaml } from "yaml";
 import { spawn } from "child_process";
 import fsExtra from "fs-extra";
+import { glob } from "glob";
 
 const { readFileSync, mkdirp, rm } = fsExtra;
 
@@ -25,38 +26,46 @@ const configOverrideTestScenarios = parseYaml(
 ).tests;
 
 const scenarios: Scenario[] = [
-  // {
-  //   name: "basic",
-  //   // No setup needed for basic scenario
-  //   tests: ["app.spec.ts"],
-  // },
-  // {
-  //   name: "with-middleware",
-  //   setup: async (cwd: string) => {
-  //     // Create a middleware.ts file
-  //     const middlewareContent = `
-  //       import type { NextRequest } from 'next/server'
-
-  //       export function middleware(request: NextRequest) {
-  //         // This is a simple middleware that doesn't modify the request
-  //         console.log('Middleware executed', request.nextUrl.pathname);
-  //       }
-
-  //       export const config = {
-  //         matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
-  //       };
-  //     `;
-
-  //     await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
-  //     console.log(`Created middleware.ts file`);
-  //   },
-  //   tests: ["middleware.spec.ts"], // Only run middleware-specific tests
-  // },
+  {
+    name: "basic",
+    // No setup needed for basic scenario
+    tests: ["app.spec.ts"],
+  },
+  {
+    name: "with-middleware",
+    setup: async (cwd: string) => {
+      // Create a middleware.ts file
+      const middlewareContent = `
+        import type { NextRequest } from 'next/server'
+
+        export function middleware(request: NextRequest) {
+          // This is a simple middleware that doesn't modify the request
+          console.log('Middleware executed', request.nextUrl.pathname);
+        }
+
+        export const config = {
+          matcher: '/((?!api|_next/static|_next/image|favicon.ico).*)',
+        };
+      `;
+
+      await fsExtra.writeFile(join(cwd, "src", "middleware.ts"), middlewareContent);
+      console.log(`Created middleware.ts file`);
+    },
+    tests: ["middleware.spec.ts"], // Only run middleware-specific tests
+  },
   ...configOverrideTestScenarios.map(
     (scenario: { name: string; config: string; file: string }) => ({
       name: scenario.name,
       setup: async (cwd: string) => {
         const configContent = scenario.config;
+
+        // Remove any existing next.config.* files
+        const configFiles = await glob(join(cwd, "next.config.*"));
+        for (const file of configFiles) {
+          await fsExtra.remove(file);
+          console.log(`Removed existing config file: ${file}`);
+        }
+
         await fsExtra.writeFile(join(cwd, scenario.file), configContent);
         console.log(`Created ${scenario.file} file with ${scenario.name} config`);
       },
diff --git a/packages/@apphosting/adapter-nextjs/package.json b/packages/@apphosting/adapter-nextjs/package.json
index d7c0246d..6403fb70 100644
--- a/packages/@apphosting/adapter-nextjs/package.json
+++ b/packages/@apphosting/adapter-nextjs/package.json
@@ -56,6 +56,7 @@
     }
   },
   "devDependencies": {
+    "glob": "^11.0.1",
     "@types/fs-extra": "*",
     "@types/mocha": "*",
     "@types/tmp": "*",

From 70e1bd804ec969651cb23245fb5dc1304f862bbb Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 14:07:19 -0500
Subject: [PATCH 12/28] add additional tests and fix lint errors

---
 .../e2e/config-override-test-cases.yaml       | 58 +++++++++++++++++++
 .../e2e/config-override.spec.ts               | 34 ++++++++++-
 2 files changed, 90 insertions(+), 2 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
index 94151b31..ee40c3b3 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override-test-cases.yaml
@@ -142,3 +142,61 @@ tests:
 
       module.exports = nextConfig
     file: next.config.js
+  - name: with-images-unoptimized-false
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        reactStrictMode: true,
+        images: {
+          unoptimized: false,
+        },
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'js-config-value',
+                },
+                {
+                  key: 'x-config-type',
+                  value: 'object',
+                },
+              ],
+            },
+          ];
+        },
+      };
+
+      module.exports = nextConfig;
+    file: next.config.js
+  - name: with-custom-image-loader
+    config: |
+      /** @type {import('next').NextConfig} */
+      const nextConfig = {
+        images: {
+          loader: "akamai",
+          path: "",
+        },
+        async headers() {
+          return [
+            {
+              source: '/:path*',
+              headers: [
+                {
+                  key: 'x-custom-header',
+                  value: 'js-config-value',
+                },
+                {
+                  key: 'x-config-type',
+                  value: 'object',
+                },
+              ],
+            },
+          ];
+        },
+      };
+
+      module.exports = nextConfig;
+    file: next.config.js
diff --git a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
index 55c0607a..a2ab5beb 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/config-override.spec.ts
@@ -27,13 +27,20 @@ const compiledFilesPath = posix.join(
   ".next",
 );
 
+const requiredServerFilePath = posix.join(compiledFilesPath, "required-server-files.json");
+
 describe("next.config override", () => {
   it("should have images optimization disabled", async function () {
-    if (scenario.includes("with-empty-config")) {
+    if (
+      scenario.includes("with-empty-config") ||
+      scenario.includes("with-images-unoptimized-false") ||
+      scenario.includes("with-custom-image-loader")
+    ) {
+      // eslint-disable-next-line @typescript-eslint/no-invalid-this
       this.skip();
     }
 
-    const serverFiles = await fsExtra.readJson(`${compiledFilesPath}/required-server-files.json`);
+    const serverFiles = await fsExtra.readJson(requiredServerFilePath);
     const config = serverFiles.config;
 
     // Verify that images.unoptimized is set to true
@@ -47,6 +54,7 @@ describe("next.config override", () => {
 
   it("should preserve other user set next configs", async function () {
     if (scenario.includes("with-empty-config")) {
+      // eslint-disable-next-line @typescript-eslint/no-invalid-this
       this.skip();
     }
 
@@ -68,6 +76,7 @@ describe("next.config override", () => {
   it("should handle function-style config correctly", async function () {
     // Only run this test for scenarios with function-style config
     if (!scenario.includes("function-style")) {
+      // eslint-disable-next-line @typescript-eslint/no-invalid-this
       this.skip();
     }
 
@@ -80,6 +89,7 @@ describe("next.config override", () => {
   it("should handle object-style config correctly", async function () {
     // Only run this test for scenarios with object-style config
     if (!scenario.includes("object-style") && !scenario.includes("with-empty-config")) {
+      // eslint-disable-next-line @typescript-eslint/no-invalid-this
       this.skip();
     }
 
@@ -92,4 +102,24 @@ describe("next.config override", () => {
       assert.equal(response.headers.get("x-config-type") ?? "", "object");
     }
   });
+
+  it("should not override images.unoptimized if user explicitly defines configs", async function () {
+    if (
+      !scenario.includes("with-images-unoptimized-false") &&
+      !scenario.includes("with-custom-image-loader")
+    ) {
+      // eslint-disable-next-line @typescript-eslint/no-invalid-this
+      this.skip();
+    }
+
+    const serverFiles = await fsExtra.readJson(requiredServerFilePath);
+    const config = serverFiles.config;
+
+    assert.ok(config.images, "Config should have images property");
+    assert.strictEqual(
+      config.images.unoptimized,
+      false,
+      "Images should have unoptimized set to false",
+    );
+  });
 });

From 442a69ad500e5e34ef7bd0ea2cd436be988cd633 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 16:18:40 -0500
Subject: [PATCH 13/28] fix lint

---
 packages/@apphosting/adapter-nextjs/e2e/run-local.ts | 1 +
 1 file changed, 1 insertion(+)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index d97f30ee..e5aa5a97 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -60,6 +60,7 @@ const scenarios: Scenario[] = [
         const configContent = scenario.config;
 
         // Remove any existing next.config.* files
+        // eslint-disable-next-line @typescript-eslint/await-thenable
         const configFiles = await glob(join(cwd, "next.config.*"));
         for (const file of configFiles) {
           await fsExtra.remove(file);

From cc64e3d53a1af39ddc62181afb56f7364b9d48c2 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 18:54:41 -0500
Subject: [PATCH 14/28] some debug logs

---
 packages/@apphosting/adapter-nextjs/e2e/run-local.ts | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index e5aa5a97..b5c9c041 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -20,10 +20,12 @@ interface Scenario {
   tests?: string[]; // List of test files to run
 }
 
+console.log(`reading config-override-test-cases.yaml`);
 // Load test data for config override
 const configOverrideTestScenarios = parseYaml(
   readFileSync(join(__dirname, "config-override-test-cases.yaml"), "utf8"),
 ).tests;
+console.log(`config-override-test-cases.yaml parsed`);
 
 const scenarios: Scenario[] = [
   {

From 560f0d8b9d2764644c6f0453bfac1fbcba2bea61 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 19:04:24 -0500
Subject: [PATCH 15/28] remove console logs

---
 packages/@apphosting/adapter-nextjs/e2e/run-local.ts | 2 --
 1 file changed, 2 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index b5c9c041..e5aa5a97 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -20,12 +20,10 @@ interface Scenario {
   tests?: string[]; // List of test files to run
 }
 
-console.log(`reading config-override-test-cases.yaml`);
 // Load test data for config override
 const configOverrideTestScenarios = parseYaml(
   readFileSync(join(__dirname, "config-override-test-cases.yaml"), "utf8"),
 ).tests;
-console.log(`config-override-test-cases.yaml parsed`);
 
 const scenarios: Scenario[] = [
   {

From 5a1ce3c82611da3292ba526db731aa7def0afc3f Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 19:14:17 -0500
Subject: [PATCH 16/28] set debuggability for e2e test

---
 packages/@apphosting/adapter-nextjs/package.json | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/@apphosting/adapter-nextjs/package.json b/packages/@apphosting/adapter-nextjs/package.json
index d823446e..e8b8829d 100644
--- a/packages/@apphosting/adapter-nextjs/package.json
+++ b/packages/@apphosting/adapter-nextjs/package.json
@@ -24,7 +24,7 @@
     "build": "rm -rf dist && tsc && chmod +x ./dist/bin/*",
     "test": "npm run test:unit && npm run test:functional",
     "test:unit": "ts-mocha -p tsconfig.json 'src/**/*.spec.ts' 'src/*.spec.ts'",
-    "test:functional": "node --loader ts-node/esm ./e2e/run-local.ts",
+    "test:functional": "NODE_DEBUG=* node --loader ts-node/esm --trace-warnings --unhandled-rejections=strict ./e2e/run-local.ts",
     "localregistry:start": "npx verdaccio --config ../publish-dev/verdaccio-config.yaml",
     "localregistry:publish": "(npm view --registry=http://localhost:4873 @apphosting/adapter-nextjs && npm unpublish --@apphosting:registry=http://localhost:4873 --force); npm publish --@apphosting:registry=http://localhost:4873"
   },

From 9d6ee74324b23326f3d06e44624a0540fa0cca28 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 20:19:14 -0500
Subject: [PATCH 17/28] remove usage of libraries to fix e2e

---
 .../@apphosting/adapter-nextjs/e2e/run-local.ts     | 13 ++++++-------
 packages/@apphosting/adapter-nextjs/package.json    |  3 +--
 2 files changed, 7 insertions(+), 9 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index e5aa5a97..042e2364 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -5,9 +5,8 @@ import { fileURLToPath } from "url";
 import { parse as parseYaml } from "yaml";
 import { spawn } from "child_process";
 import fsExtra from "fs-extra";
-import { glob } from "glob";
 
-const { readFileSync, mkdirp, rm } = fsExtra;
+const { readFileSync, mkdirp, rmdir } = fsExtra;
 
 const __dirname = dirname(fileURLToPath(import.meta.url));
 
@@ -58,10 +57,10 @@ const scenarios: Scenario[] = [
       name: scenario.name,
       setup: async (cwd: string) => {
         const configContent = scenario.config;
-
-        // Remove any existing next.config.* files
-        // eslint-disable-next-line @typescript-eslint/await-thenable
-        const configFiles = await glob(join(cwd, "next.config.*"));
+        const files = await fsExtra.readdir(cwd);
+        const configFiles = files.filter(file => file.startsWith('next.config.'))
+                                 .map(file => join(cwd, file));
+        
         for (const file of configFiles) {
           await fsExtra.remove(file);
           console.log(`Removed existing config file: ${file}`);
@@ -77,7 +76,7 @@ const scenarios: Scenario[] = [
 
 const errors: any[] = [];
 
-await rm(join(__dirname, "runs"), { recursive: true }).catch(() => undefined);
+await rmdir(join(__dirname, "runs"), { recursive: true }).catch(() => undefined);
 
 // Run each scenario
 for (const scenario of scenarios) {
diff --git a/packages/@apphosting/adapter-nextjs/package.json b/packages/@apphosting/adapter-nextjs/package.json
index e8b8829d..99bafabc 100644
--- a/packages/@apphosting/adapter-nextjs/package.json
+++ b/packages/@apphosting/adapter-nextjs/package.json
@@ -24,7 +24,7 @@
     "build": "rm -rf dist && tsc && chmod +x ./dist/bin/*",
     "test": "npm run test:unit && npm run test:functional",
     "test:unit": "ts-mocha -p tsconfig.json 'src/**/*.spec.ts' 'src/*.spec.ts'",
-    "test:functional": "NODE_DEBUG=* node --loader ts-node/esm --trace-warnings --unhandled-rejections=strict ./e2e/run-local.ts",
+    "test:functional": "node --loader ts-node/esm ./e2e/run-local.ts",
     "localregistry:start": "npx verdaccio --config ../publish-dev/verdaccio-config.yaml",
     "localregistry:publish": "(npm view --registry=http://localhost:4873 @apphosting/adapter-nextjs && npm unpublish --@apphosting:registry=http://localhost:4873 --force); npm publish --@apphosting:registry=http://localhost:4873"
   },
@@ -56,7 +56,6 @@
     }
   },
   "devDependencies": {
-    "glob": "^11.0.1",
     "@types/fs-extra": "*",
     "@types/mocha": "*",
     "@types/tmp": "*",

From be9d381dd02226cd8f5e2d69727695d86b33f56a Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 20:30:47 -0500
Subject: [PATCH 18/28] fix e2e

---
 packages/@apphosting/adapter-nextjs/e2e/run-local.ts | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
index 042e2364..23104afa 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/run-local.ts
@@ -58,9 +58,10 @@ const scenarios: Scenario[] = [
       setup: async (cwd: string) => {
         const configContent = scenario.config;
         const files = await fsExtra.readdir(cwd);
-        const configFiles = files.filter(file => file.startsWith('next.config.'))
-                                 .map(file => join(cwd, file));
-        
+        const configFiles = files
+          .filter((file) => file.startsWith("next.config."))
+          .map((file) => join(cwd, file));
+
         for (const file of configFiles) {
           await fsExtra.remove(file);
           console.log(`Removed existing config file: ${file}`);

From 9797602161b2573ee641330e14745b9d3c447c07 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Thu, 6 Mar 2025 21:08:01 -0500
Subject: [PATCH 19/28] add jsdocs

---
 .../@apphosting/adapter-nextjs/src/overrides.ts   | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index f5a748ec..ab9bd9ca 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -9,6 +9,10 @@ import {
 import { join } from "path";
 import { rename as renamePromise } from "fs/promises";
 
+/**
+ * Overrides the user's Next Config file (next.config.[ts|js|mjs]) to add configs
+ * optimized for Firebase App Hosting.
+ */
 export async function overrideNextConfig(projectRoot: string, nextConfigFileName: string) {
   // Check if the file exists in the current working directory
   const configPath = join(projectRoot, nextConfigFileName);
@@ -52,6 +56,17 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
   }
 }
 
+/**
+ * Returns a custom Next.js config that optimizes the app for Firebase App Hosting.
+ *
+ * Current overrides include:
+ * - images.unoptimized = true, unless user explicitly sets images.unoptimized to false or
+ * is using a custom image loader.
+ *
+ * @param importStatement The import statement for the original config.
+ * @param fileExtension The file extension of the original config.
+ * @returns The custom Next.js config.
+ */
 function getCustomNextConfig(importStatement: string, fileExtension: string) {
   return `
   // @ts-nocheck

From 2bdecf00a5081807c0bbe285e7280a97324c1c8b Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusan@google.com>
Date: Sat, 8 Mar 2025 04:36:47 +0000
Subject: [PATCH 20/28] bump version

---
 package-lock.json                             | 105 +-----------------
 .../@apphosting/adapter-nextjs/package.json   |   2 +-
 2 files changed, 2 insertions(+), 105 deletions(-)

diff --git a/package-lock.json b/package-lock.json
index 499d8791..27eda41d 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -19774,12 +19774,6 @@
         "url": "https://github.com/sponsors/sindresorhus"
       }
     },
-    "node_modules/package-json-from-dist": {
-      "version": "1.0.1",
-      "resolved": "https://registry.npmjs.org/package-json-from-dist/-/package-json-from-dist-1.0.1.tgz",
-      "integrity": "sha512-UEZIS3/by4OC8vL3P2dTXRETpebLI2NiI5vIrjaD/5UtrkFX/tNbwjTSRAGC/+7CAo2pIcBaRgWmcBBHcsaCIw==",
-      "dev": true
-    },
     "node_modules/pacote": {
       "version": "15.2.0",
       "resolved": "https://registry.npmjs.org/pacote/-/pacote-15.2.0.tgz",
@@ -25624,7 +25618,7 @@
       }
     },
     "packages/@apphosting/adapter-nextjs": {
-      "version": "14.0.11",
+      "version": "14.0.12",
       "license": "Apache-2.0",
       "dependencies": {
         "@apphosting/common": "*",
@@ -25639,7 +25633,6 @@
         "@types/fs-extra": "*",
         "@types/mocha": "*",
         "@types/tmp": "*",
-        "glob": "^11.0.1",
         "mocha": "*",
         "next": "~14.0.0",
         "semver": "*",
@@ -25658,102 +25651,6 @@
         }
       }
     },
-    "packages/@apphosting/adapter-nextjs/node_modules/brace-expansion": {
-      "version": "2.0.1",
-      "resolved": "https://registry.npmjs.org/brace-expansion/-/brace-expansion-2.0.1.tgz",
-      "integrity": "sha512-XnAIvQ8eM+kC6aULx6wuQiwVsnzsi9d3WxzV3FpWTGA19F621kwdbsAcFKXgKUHZWsy+mY6iL1sHTxWEFCytDA==",
-      "dev": true,
-      "dependencies": {
-        "balanced-match": "^1.0.0"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/glob": {
-      "version": "11.0.1",
-      "resolved": "https://registry.npmjs.org/glob/-/glob-11.0.1.tgz",
-      "integrity": "sha512-zrQDm8XPnYEKawJScsnM0QzobJxlT/kHOOlRTio8IH/GrmxRE5fjllkzdaHclIuNjUQTJYH2xHNIGfdpJkDJUw==",
-      "dev": true,
-      "dependencies": {
-        "foreground-child": "^3.1.0",
-        "jackspeak": "^4.0.1",
-        "minimatch": "^10.0.0",
-        "minipass": "^7.1.2",
-        "package-json-from-dist": "^1.0.0",
-        "path-scurry": "^2.0.0"
-      },
-      "bin": {
-        "glob": "dist/esm/bin.mjs"
-      },
-      "engines": {
-        "node": "20 || >=22"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/jackspeak": {
-      "version": "4.1.0",
-      "resolved": "https://registry.npmjs.org/jackspeak/-/jackspeak-4.1.0.tgz",
-      "integrity": "sha512-9DDdhb5j6cpeitCbvLO7n7J4IxnbM6hoF6O1g4HQ5TfhvvKN8ywDM7668ZhMHRqVmxqhps/F6syWK2KcPxYlkw==",
-      "dev": true,
-      "dependencies": {
-        "@isaacs/cliui": "^8.0.2"
-      },
-      "engines": {
-        "node": "20 || >=22"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/lru-cache": {
-      "version": "11.0.2",
-      "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-11.0.2.tgz",
-      "integrity": "sha512-123qHRfJBmo2jXDbo/a5YOQrJoHF/GNQTLzQ5+IdK5pWpceK17yRc6ozlWd25FxvGKQbIUs91fDFkXmDHTKcyA==",
-      "dev": true,
-      "engines": {
-        "node": "20 || >=22"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/minimatch": {
-      "version": "10.0.1",
-      "resolved": "https://registry.npmjs.org/minimatch/-/minimatch-10.0.1.tgz",
-      "integrity": "sha512-ethXTt3SGGR+95gudmqJ1eNhRO7eGEGIgYA9vnPatK4/etz2MEVDno5GMCibdMTuBMyElzIlgxMna3K94XDIDQ==",
-      "dev": true,
-      "dependencies": {
-        "brace-expansion": "^2.0.1"
-      },
-      "engines": {
-        "node": "20 || >=22"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/minipass": {
-      "version": "7.1.2",
-      "resolved": "https://registry.npmjs.org/minipass/-/minipass-7.1.2.tgz",
-      "integrity": "sha512-qOOzS1cBTWYF4BH8fVePDBOO9iptMnGUEZwNc/cMWnTV2nVLZ7VoNWEPHkYczZA0pdoA7dl6e7FL659nX9S2aw==",
-      "dev": true,
-      "engines": {
-        "node": ">=16 || 14 >=14.17"
-      }
-    },
-    "packages/@apphosting/adapter-nextjs/node_modules/path-scurry": {
-      "version": "2.0.0",
-      "resolved": "https://registry.npmjs.org/path-scurry/-/path-scurry-2.0.0.tgz",
-      "integrity": "sha512-ypGJsmGtdXUOeM5u93TyeIEfEhM6s+ljAhrk5vAvSx8uyY/02OvrZnA0YNGUrPXfpJMgI1ODd3nwz8Npx4O4cg==",
-      "dev": true,
-      "dependencies": {
-        "lru-cache": "^11.0.0",
-        "minipass": "^7.1.2"
-      },
-      "engines": {
-        "node": "20 || >=22"
-      },
-      "funding": {
-        "url": "https://github.com/sponsors/isaacs"
-      }
-    },
     "packages/@apphosting/build": {
       "version": "0.1.0",
       "license": "Apache-2.0",
diff --git a/packages/@apphosting/adapter-nextjs/package.json b/packages/@apphosting/adapter-nextjs/package.json
index 99bafabc..e9105f40 100644
--- a/packages/@apphosting/adapter-nextjs/package.json
+++ b/packages/@apphosting/adapter-nextjs/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@apphosting/adapter-nextjs",
-  "version": "14.0.11",
+  "version": "14.0.12",
   "main": "dist/index.js",
   "description": "Experimental addon to the Firebase CLI to add web framework support",
   "repository": {

From 85cea6e61c0038853ad4a05e685de3fff4ef2f7c Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Sat, 8 Mar 2025 10:17:04 -0500
Subject: [PATCH 21/28] address pr comments

---
 .../adapter-nextjs/src/overrides.ts           | 34 ++++++++++++-------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index ab9bd9ca..b6b506d6 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -6,7 +6,7 @@ import {
   exists,
   writeFile,
 } from "./utils.js";
-import { join } from "path";
+import { join, extname } from "path";
 import { rename as renamePromise } from "fs/promises";
 
 /**
@@ -23,9 +23,8 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
   }
 
   // Determine the file extension
-  const fileExtension = nextConfigFileName.split(".").pop() || "js";
+  const fileExtension = extname(nextConfigFileName);
   const originalConfigName = `next.config.original.${fileExtension}`;
-  const newConfigName = `next.config.${fileExtension}`;
 
   // Rename the original config file
   try {
@@ -34,22 +33,31 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
 
     // Create a new config file with the appropriate import
     let importStatement;
-    if (fileExtension === "js" || fileExtension === "cjs") {
-      importStatement = `const originalConfig = require('./${originalConfigName}');`;
-    } else if (fileExtension === "mjs") {
-      importStatement = `import originalConfig from './${originalConfigName}';`;
-    } else if (fileExtension === "ts") {
-      importStatement = `import originalConfig from './${originalConfigName.replace(".ts", "")}';`;
-    } else {
-      throw new Error(`Unsupported file extension: ${fileExtension}`);
+    switch (fileExtension) {
+      case "js":
+        importStatement = `const originalConfig = require('./${originalConfigName}');`;
+        break;
+      case "mjs":
+        importStatement = `import originalConfig from './${originalConfigName}';`;
+        break;
+      case "ts":
+        importStatement = `import originalConfig from './${originalConfigName.replace(
+          ".ts",
+          "",
+        )}';`;
+        break;
+      default:
+        throw new Error(
+          `Unsupported file extension for Next Config: "${fileExtension}", please use "js", "mjs", or "ts"`,
+        );
     }
 
     // Create the new config content with our overrides
     const newConfigContent = getCustomNextConfig(importStatement, fileExtension);
 
     // Write the new config file
-    await writeFile(join(projectRoot, newConfigName), newConfigContent);
-    console.log(`Successfully created ${newConfigName} with Firebase App Hosting overrides`);
+    await writeFile(join(projectRoot, nextConfigFileName), newConfigContent);
+    console.log(`Successfully created ${nextConfigFileName} with Firebase App Hosting overrides`);
   } catch (error) {
     console.error(`Error overriding Next.js config: ${error}`);
     throw error;

From fff350541b5ca6f94876346263d603a39100cafd Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Sat, 8 Mar 2025 10:29:05 -0500
Subject: [PATCH 22/28] fix errors

---
 .../@apphosting/adapter-nextjs/src/overrides.ts    | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index b6b506d6..4c22e65f 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -24,7 +24,7 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
 
   // Determine the file extension
   const fileExtension = extname(nextConfigFileName);
-  const originalConfigName = `next.config.original.${fileExtension}`;
+  const originalConfigName = `next.config.original${fileExtension}`;
 
   // Rename the original config file
   try {
@@ -34,13 +34,13 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
     // Create a new config file with the appropriate import
     let importStatement;
     switch (fileExtension) {
-      case "js":
+      case ".js":
         importStatement = `const originalConfig = require('./${originalConfigName}');`;
         break;
-      case "mjs":
+      case ".mjs":
         importStatement = `import originalConfig from './${originalConfigName}';`;
         break;
-      case "ts":
+      case ".ts":
         importStatement = `import originalConfig from './${originalConfigName.replace(
           ".ts",
           "",
@@ -48,7 +48,7 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
         break;
       default:
         throw new Error(
-          `Unsupported file extension for Next Config: "${fileExtension}", please use "js", "mjs", or "ts"`,
+          `Unsupported file extension for Next Config: "${fileExtension}", please use ".js", ".mjs", or ".ts"`,
         );
     }
 
@@ -72,7 +72,7 @@ export async function overrideNextConfig(projectRoot: string, nextConfigFileName
  * is using a custom image loader.
  *
  * @param importStatement The import statement for the original config.
- * @param fileExtension The file extension of the original config.
+ * @param fileExtension The file extension of the original config. Use ".js", ".mjs", or ".ts"
  * @returns The custom Next.js config.
  */
 function getCustomNextConfig(importStatement: string, fileExtension: string) {
@@ -98,7 +98,7 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
       }
     : fahOptimizedConfig(originalConfig);
 
-  ${fileExtension === "mjs" ? "export default config;" : "module.exports = config;"}
+  ${fileExtension === ".mjs" ? "export default config;" : "module.exports = config;"}
   `;
 }
 

From a2dc2ebf09691fbcbb915570bbac54e54565fb0e Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Sat, 8 Mar 2025 13:13:16 -0500
Subject: [PATCH 23/28] add validate next config override function

---
 .../adapter-nextjs/src/bin/build.ts           | 21 ++++++++++++++-----
 .../adapter-nextjs/src/overrides.spec.ts      | 10 +++++++++
 .../adapter-nextjs/src/overrides.ts           | 18 ++++++++++++++++
 3 files changed, 44 insertions(+), 5 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
index eb2e525a..d7d155f2 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
@@ -8,7 +8,11 @@ import {
 } from "../utils.js";
 import { join } from "path";
 import { getBuildOptions, runBuild } from "@apphosting/common";
-import { addRouteOverrides, overrideNextConfig } from "../overrides.js";
+import {
+  addRouteOverrides,
+  overrideNextConfig,
+  validateNextConfigOverrides,
+} from "../overrides.js";
 
 const root = process.cwd();
 const opts = getBuildOptions();
@@ -21,19 +25,26 @@ if (!process.env.FRAMEWORK_VERSION) {
   throw new Error("Could not find the nextjs version of the application");
 }
 
-const { distDir, configFileName } = await loadConfig(root, opts.projectDirectory);
-await overrideNextConfig(root, configFileName);
+const originalConfig = await loadConfig(root, opts.projectDirectory);
+
+await overrideNextConfig(root, originalConfig.configFileName);
+await validateNextConfigOverrides(root, opts.projectDirectory);
+
 await runBuild();
 
 const adapterMetadata = getAdapterMetadata();
-const nextBuildDirectory = join(opts.projectDirectory, distDir);
+const nextBuildDirectory = join(opts.projectDirectory, originalConfig.distDir);
 const outputBundleOptions = populateOutputBundleOptions(
   root,
   opts.projectDirectory,
   nextBuildDirectory,
 );
 
-await addRouteOverrides(outputBundleOptions.outputDirectoryAppPath, distDir, adapterMetadata);
+await addRouteOverrides(
+  outputBundleOptions.outputDirectoryAppPath,
+  originalConfig.distDir,
+  adapterMetadata,
+);
 
 await generateBuildOutput(
   root,
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index 326d1f2b..96a6c9cf 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -314,6 +314,16 @@ describe("next config overrides", () => {
       `),
     );
   });
+
+  it("should not do anything if no next.config.* file exists", async () => {
+    const { overrideNextConfig } = await importOverrides;
+    await overrideNextConfig(tmpDir, "next.config.js");
+
+    // Assert that no next.config* files were created
+    const files = fs.readdirSync(tmpDir);
+    const nextConfigFiles = files.filter((file) => file.startsWith("next.config"));
+    assert.strictEqual(nextConfigFiles.length, 0, "No next.config files should exist");
+  });
 });
 
 // Normalize whitespace for comparison
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index 4c22e65f..ace59438 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -5,9 +5,11 @@ import {
   loadMiddlewareManifest,
   exists,
   writeFile,
+  loadConfig,
 } from "./utils.js";
 import { join, extname } from "path";
 import { rename as renamePromise } from "fs/promises";
+import { NextConfigComplete } from "next/dist/server/config-shared.js";
 
 /**
  * Overrides the user's Next Config file (next.config.[ts|js|mjs]) to add configs
@@ -98,10 +100,26 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
       }
     : fahOptimizedConfig(originalConfig);
 
+  const firebaseAppHostingSymbol = Symbol("__createdByFirebaseAppHosting__");
+  config[firebaseAppHostingSymbol] = true;
+
   ${fileExtension === ".mjs" ? "export default config;" : "module.exports = config;"}
   `;
 }
 
+export async function validateNextConfigOverrides(root: string, projectRoot: string) {
+  try {
+    const overriddenConfig = await loadConfig(root, projectRoot);
+    if (!overriddenConfig.__createdByFirebaseAppHosting__) {
+      throw new Error("Firebase App Hosting overrides are missing");
+    }
+  } catch (error) {
+    throw new Error(
+      `Invalid Next.js config: ${error instanceof Error ? error.message : "Unknown error"}`,
+    );
+  }
+}
+
 /**
  * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting
  * specific overrides (i.e headers).

From bd62abe9627acf93af7202e35ca6eda531d68979 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Sat, 8 Mar 2025 14:01:54 -0500
Subject: [PATCH 24/28] just loadconfig again instead of checking anything else

---
 packages/@apphosting/adapter-nextjs/src/overrides.ts | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index ace59438..b7da8424 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -100,19 +100,13 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
       }
     : fahOptimizedConfig(originalConfig);
 
-  const firebaseAppHostingSymbol = Symbol("__createdByFirebaseAppHosting__");
-  config[firebaseAppHostingSymbol] = true;
-
   ${fileExtension === ".mjs" ? "export default config;" : "module.exports = config;"}
   `;
 }
 
 export async function validateNextConfigOverrides(root: string, projectRoot: string) {
   try {
-    const overriddenConfig = await loadConfig(root, projectRoot);
-    if (!overriddenConfig.__createdByFirebaseAppHosting__) {
-      throw new Error("Firebase App Hosting overrides are missing");
-    }
+    await loadConfig(root, projectRoot);
   } catch (error) {
     throw new Error(
       `Invalid Next.js config: ${error instanceof Error ? error.message : "Unknown error"}`,

From 726342e8681a01cf0972b2c63297d50547121222 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusan@google.com>
Date: Mon, 10 Mar 2025 16:35:34 +0000
Subject: [PATCH 25/28] fix breaking tests

---
 packages/@apphosting/adapter-nextjs/e2e/app.spec.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
index a95650f6..a50ce219 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
@@ -19,14 +19,14 @@ describe("app", () => {
     const response = await fetch(host);
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
   });
 
   it("/ssg", async () => {
     const response = await fetch(posix.join(host, "ssg"));
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
     const text = await response.text();
     assert.ok(text.includes("SSG"));
     assert.ok(text.includes("Generated"));
@@ -81,7 +81,7 @@ describe("app", () => {
     const response = await fetch(posix.join(host, "isr", "demand"));
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
     const text = await response.text();
     assert.ok(text.includes("A cached page"));
     assert.ok(text.includes("Generated"));

From d7ce5da2d01a4c06cd7182c03686b9f3af95851b Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusan@google.com>
Date: Mon, 10 Mar 2025 16:35:57 +0000
Subject: [PATCH 26/28] add validation that override worked

---
 .../adapter-nextjs/src/bin/build.ts           | 25 +++++++----
 .../adapter-nextjs/src/overrides.ts           | 41 ++++++++++++++++---
 2 files changed, 53 insertions(+), 13 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/src/bin/build.ts b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
index d7d155f2..eedb6bbb 100644
--- a/packages/@apphosting/adapter-nextjs/src/bin/build.ts
+++ b/packages/@apphosting/adapter-nextjs/src/bin/build.ts
@@ -5,14 +5,11 @@ import {
   generateBuildOutput,
   validateOutputDirectory,
   getAdapterMetadata,
+  exists,
 } from "../utils.js";
 import { join } from "path";
 import { getBuildOptions, runBuild } from "@apphosting/common";
-import {
-  addRouteOverrides,
-  overrideNextConfig,
-  validateNextConfigOverrides,
-} from "../overrides.js";
+import { addRouteOverrides, overrideNextConfig, validateNextConfigOverride } from "../overrides.js";
 
 const root = process.cwd();
 const opts = getBuildOptions();
@@ -27,8 +24,22 @@ if (!process.env.FRAMEWORK_VERSION) {
 
 const originalConfig = await loadConfig(root, opts.projectDirectory);
 
-await overrideNextConfig(root, originalConfig.configFileName);
-await validateNextConfigOverrides(root, opts.projectDirectory);
+/**
+ * Override user's Next Config to optimize the app for Firebase App Hosting
+ * and validate that the override resulted in a valid config that Next.js can
+ * load.
+ *
+ * If the app does not have a next.config.[js|mjs|ts] file in the first place,
+ * then can skip config override.
+ *
+ * Note: loadConfig always returns a fileName (default: next.config.js) even if
+ * one does not exist in the app's root: https://github.com/vercel/next.js/blob/23681508ca34b66a6ef55965c5eac57de20eb67f/packages/next/src/server/config.ts#L1115
+ */
+const originalConfigPath = join(root, originalConfig.configFileName);
+if (await exists(originalConfigPath)) {
+  await overrideNextConfig(root, originalConfig.configFileName);
+  await validateNextConfigOverride(root, opts.projectDirectory, originalConfig.configFileName);
+}
 
 await runBuild();
 
diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.ts b/packages/@apphosting/adapter-nextjs/src/overrides.ts
index b7da8424..d680e319 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.ts
@@ -9,13 +9,13 @@ import {
 } from "./utils.js";
 import { join, extname } from "path";
 import { rename as renamePromise } from "fs/promises";
-import { NextConfigComplete } from "next/dist/server/config-shared.js";
 
 /**
  * Overrides the user's Next Config file (next.config.[ts|js|mjs]) to add configs
  * optimized for Firebase App Hosting.
  */
 export async function overrideNextConfig(projectRoot: string, nextConfigFileName: string) {
+  console.log(`Overriding Next Config to add configs optmized for Firebase App Hosting`);
   // Check if the file exists in the current working directory
   const configPath = join(projectRoot, nextConfigFileName);
 
@@ -87,13 +87,13 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
     ...config,
     images: {
       ...(config.images || {}),
-      ...(config.images?.unoptimized === undefined && config.images?.loader === undefined 
-          ? { unoptimized: true } 
+      ...(config.images?.unoptimized === undefined && config.images?.loader === undefined
+          ? { unoptimized: true }
           : {}),
     },
   });
 
-  const config = typeof originalConfig === 'function' 
+  const config = typeof originalConfig === 'function'
     ? async (...args) => {
         const resolvedConfig = await originalConfig(...args);
         return fahOptimizedConfig(resolvedConfig);
@@ -104,12 +104,41 @@ function getCustomNextConfig(importStatement: string, fileExtension: string) {
   `;
 }
 
-export async function validateNextConfigOverrides(root: string, projectRoot: string) {
+/**
+ * This function is used to validate the state of an app after running the
+ * overrideNextConfig. It validates that:
+ *  1. original next config is preserved
+ *  2. a new next config is created
+ *  3. new next config can be loaded by NextJs without any issues.
+ */
+export async function validateNextConfigOverride(
+  root: string,
+  projectRoot: string,
+  originalConfigFileName: string,
+) {
+  const originalConfigExtension = extname(originalConfigFileName);
+  const newConfigFileName = `next.config.original${originalConfigExtension}`;
+  const newConfigFilePath = join(root, newConfigFileName);
+  if (!(await exists(newConfigFilePath))) {
+    throw new Error(
+      `Next Config Override Failed: New Next.js config file not found at ${newConfigFilePath}`,
+    );
+  }
+
+  const originalNextConfigFilePath = join(root, originalConfigFileName);
+  if (!(await exists(originalNextConfigFilePath))) {
+    throw new Error(
+      `Next Config Override Failed: Original Next.js config file not found at ${originalNextConfigFilePath}`,
+    );
+  }
+
   try {
     await loadConfig(root, projectRoot);
   } catch (error) {
     throw new Error(
-      `Invalid Next.js config: ${error instanceof Error ? error.message : "Unknown error"}`,
+      `Resulting Next Config is invalid: ${
+        error instanceof Error ? error.message : "Unknown error"
+      }`,
     );
   }
 }

From ec84af397ccada5b88b192d50a12c0c212e7e3f9 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusan@google.com>
Date: Mon, 10 Mar 2025 16:55:06 +0000
Subject: [PATCH 27/28] fix tests again

---
 packages/@apphosting/adapter-nextjs/e2e/app.spec.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts b/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
index a50ce219..a95650f6 100644
--- a/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/e2e/app.spec.ts
@@ -19,14 +19,14 @@ describe("app", () => {
     const response = await fetch(host);
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
   });
 
   it("/ssg", async () => {
     const response = await fetch(posix.join(host, "ssg"));
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
     const text = await response.text();
     assert.ok(text.includes("SSG"));
     assert.ok(text.includes("Generated"));
@@ -81,7 +81,7 @@ describe("app", () => {
     const response = await fetch(posix.join(host, "isr", "demand"));
     assert.ok(response.ok);
     assert.equal(response.headers.get("content-type")?.toLowerCase(), "text/html; charset=utf-8");
-    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000,");
+    assert.equal(response.headers.get("cache-control"), "s-maxage=31536000, ");
     const text = await response.text();
     assert.ok(text.includes("A cached page"));
     assert.ok(text.includes("Generated"));

From 705535081a39c9c94715731e1f89c73b095fae83 Mon Sep 17 00:00:00 2001
From: Mathusan Selvarajah <mathusans52@gmail.com>
Date: Mon, 10 Mar 2025 14:40:49 -0400
Subject: [PATCH 28/28] add overrides validation unit tests

---
 .../adapter-nextjs/src/overrides.spec.ts      | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
index 96a6c9cf..3d478b18 100644
--- a/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
+++ b/packages/@apphosting/adapter-nextjs/src/overrides.spec.ts
@@ -326,6 +326,54 @@ describe("next config overrides", () => {
   });
 });
 
+describe("validateNextConfigOverride", () => {
+  let tmpDir: string;
+  let root: string;
+  let projectRoot: string;
+  let originalConfigFileName: string;
+  let newConfigFileName: string;
+  let originalConfigPath: string;
+  let newConfigPath: string;
+
+  beforeEach(() => {
+    tmpDir = fs.mkdtempSync(path.join(os.tmpdir(), "test-next-config-override"));
+    root = tmpDir;
+    projectRoot = tmpDir;
+    originalConfigFileName = "next.config.js";
+    newConfigFileName = "next.config.original.js";
+    originalConfigPath = path.join(root, originalConfigFileName);
+    newConfigPath = path.join(root, newConfigFileName);
+
+    fs.mkdirSync(root, { recursive: true });
+  });
+
+  afterEach(() => {
+    fs.rmSync(tmpDir, { recursive: true, force: true });
+  });
+
+  it("should throw an error when new config file doesn't exist", async () => {
+    fs.writeFileSync(originalConfigPath, "module.exports = {}");
+
+    const { validateNextConfigOverride } = await importOverrides;
+
+    await assert.rejects(
+      async () => await validateNextConfigOverride(root, projectRoot, originalConfigFileName),
+      /New Next.js config file not found/,
+    );
+  });
+
+  it("should throw an error when original config file doesn't exist", async () => {
+    fs.writeFileSync(newConfigPath, "module.exports = {}");
+
+    const { validateNextConfigOverride } = await importOverrides;
+
+    await assert.rejects(
+      async () => await validateNextConfigOverride(root, projectRoot, originalConfigFileName),
+      /Original Next.js config file not found/,
+    );
+  });
+});
+
 // Normalize whitespace for comparison
 function normalizeWhitespace(str: string) {
   return str.replace(/\s+/g, " ").trim();