Restore Next config after build.

packages/@apphosting/adapter-nextjs/src/bin/build.spec.ts

@@ -32,6 +32,10 @@ describe("build commands", () => {
   it("expects all output bundle files to be generated", async () => {
     const { generateBuildOutput, validateOutputDirectory } = await importUtils;
     const files = {
+      // .next/standalone/.next/ must be created beforehand otherwise
+      // generateBuildOutput will attempt to copy
+      // .next/ into .next/standalone/.next
+      ".next/standalone/.next/package.json": "",
       ".next/standalone/server.js": "",
       ".next/static/staticfile": "",
       ".next/routes-manifest.json": `{
@@ -53,7 +57,13 @@ describe("build commands", () => {
 
     const expectedFiles = {
       ".next/standalone/.next/static/staticfile": "",
+      ".next/static/staticfile": "",
       ".next/standalone/server.js": "",
+      ".next/routes-manifest.json": `{
+        "headers":[],
+        "rewrites":[],
+        "redirects":[]
+      }`,
       ".apphosting/bundle.yaml": `version: v1
 runConfig:
   runCommand: node .next/standalone/server.js
@@ -71,7 +81,7 @@ outputFiles:
     validateTestFiles(tmpDir, expectedFiles);
   });
 
-  it("moves files into correct location in a monorepo setup", async () => {
+  it("copies files into correct location in a monorepo setup", async () => {
     const { generateBuildOutput } = await importUtils;
     const files = {
       ".next/standalone/apps/next-app/standalonefile": "",
@@ -113,6 +123,7 @@ outputFiles:
     const expectedFiles = {
       ".next/standalone/apps/next-app/.next/static/staticfile": "",
       ".next/standalone/apps/next-app/standalonefile": "",
+      ".next/static/staticfile": "",
     };
     const expectedPartialYaml = {
       version: "v1",
@@ -125,6 +136,10 @@ outputFiles:
   it("test failed validateOutputDirectory", async () => {
     const { generateBuildOutput, validateOutputDirectory } = await importUtils;
     const files = {
+      // .next/standalone/.next/ must be created beforehand otherwise
+      // generateBuildOutput will attempt to copy
+      // .next/ into .next/standalone/.next
+      ".next/standalone/.next/package.json": "",
       ".next/standalone/notserver.js": "",
       ".next/static/staticfile": "",
       ".next/routes-manifest.json": `{
@@ -152,6 +167,10 @@ outputFiles:
   it("expects directories and other files to be copied over", async () => {
     const { generateBuildOutput, validateOutputDirectory } = await importUtils;
     const files = {
+      // .next/standalone/.next/ must be created beforehand otherwise
+      // generateBuildOutput will attempt to copy
+      // .next/ into .next/standalone/.next
+      ".next/standalone/.next/package.json": "",
       ".next/standalone/server.js": "",
       ".next/static/staticfile": "",
       "public/publicfile": "",
@@ -178,9 +197,15 @@ outputFiles:
 
     const expectedFiles = {
       ".next/standalone/.next/static/staticfile": "",
+      ".next/static/staticfile": "",
       ".next/standalone/server.js": "",
       ".next/standalone/public/publicfile": "",
       ".next/standalone/extrafile": "",
+      ".next/routes-manifest.json": `{
+        "headers":[],
+        "rewrites":[],
+        "redirects":[]
+      }`,
     };
     validateTestFiles(tmpDir, expectedFiles);
   });

packages/@apphosting/adapter-nextjs/src/bin/build.ts

@@ -9,7 +9,7 @@
 } from "../utils.js";
 import { join } from "path";
 import { getBuildOptions, runBuild } from "@apphosting/common";
-import { addRouteOverrides, overrideNextConfig, validateNextConfigOverride } from "../overrides.js";
+import { addRouteOverrides, overrideNextConfig, restoreNextConfig, validateNextConfigOverride } from "../overrides.js";
 
 const root = process.cwd();
 const opts = getBuildOptions();
@@ -19,29 +19,33 @@
 // Opt-out sending telemetry to Vercel
 process.env.NEXT_TELEMETRY_DISABLED = "1";
 
-const originalConfig = await loadConfig(root, opts.projectDirectory);
+const nextConfig = await loadConfig(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.
  *
+ * We restore the user's Next Config at the end of the build, after the config file has been
+ * copied over to the output directory, so that the user's original code is not modified.
+ *
  * 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);
+const nextConfigPath = join(root, nextConfig.configFileName);
+if (await exists(nextConfigPath)) {
+  await overrideNextConfig(root, nextConfig.configFileName);
+  await validateNextConfigOverride(root, opts.projectDirectory, nextConfig.configFileName);
 }
 
 await runBuild();
 
+
 const adapterMetadata = getAdapterMetadata();
-const nextBuildDirectory = join(opts.projectDirectory, originalConfig.distDir);
+const nextBuildDirectory = join(opts.projectDirectory, nextConfig.distDir);
 const outputBundleOptions = populateOutputBundleOptions(
   root,
   opts.projectDirectory,
@@ -50,7 +54,7 @@
 
 await addRouteOverrides(
   outputBundleOptions.outputDirectoryAppPath,
-  originalConfig.distDir,
+  nextConfig.distDir,
   adapterMetadata,
 );
 
@@ -64,3 +68,5 @@
   adapterMetadata,
 );
 await validateOutputDirectory(outputBundleOptions, nextBuildDirectory);
+
+await restoreNextConfig(root, nextConfig.configFileName);

packages/@apphosting/adapter-nextjs/src/overrides.ts

@@ -142,6 +142,34 @@
   }
 }
 
+/**
+ *
+ */
+export async function restoreNextConfig(projectRoot: string, nextConfigFileName: string) {
+  // Check if the file exists in the current working directory
+  const configPath = join(projectRoot, nextConfigFileName);
+  if (!(await exists(configPath))) {
+    return;
+  }
+
+  // Determine the file extension
+  const fileExtension = extname(nextConfigFileName);
+  const originalConfigPath = join(projectRoot, `next.config.original${fileExtension}`);
+  if (!(await exists(originalConfigPath))) {
+    console.warn(`next config may have been overwritten but original contents not found`);
+    return;
+  }
+  console.log(`Restoring original next config in project root`);
+
+  try {
+    await renamePromise(originalConfigPath, configPath);
+  } catch (error) {
+    console.error(`Error restoring Next config: ${error}`);
+  }
+  return;
+
+}
+
 /**
  * Modifies the app's route manifest (routes-manifest.json) to add Firebase App Hosting
  * specific overrides (i.e headers).

packages/@apphosting/adapter-nextjs/src/utils.ts

@@ -15,7 +15,7 @@ import { NextConfigComplete } from "next/dist/server/config-shared.js";
 import { OutputBundleConfig } from "@apphosting/common";
 
 // fs-extra is CJS, readJson can't be imported using shorthand
-export const { move, exists, writeFile, readJson, readdir, readFileSync, existsSync, mkdir } =
+export const { copy, exists, writeFile, readJson, readdir, readFileSync, existsSync, mkdir } =
   fsExtra;
 
 // Loads the user's next.config.js file.
@@ -116,7 +116,7 @@ export function populateOutputBundleOptions(
 }
 
 /**
- * Moves static assets and other resources into the standlone directory, also generates the bundle.yaml
+ * Copy static assets and other resources into the standlone directory, also generates the bundle.yaml
  * @param rootDir The root directory of the uploaded source code.
  * @param outputBundleOptions The target location of built artifacts in the output bundle.
  * @param nextBuildDirectory The location of the .next directory.
@@ -131,30 +131,30 @@ export async function generateBuildOutput(
 ): Promise<void> {
   const staticDirectory = join(nextBuildDirectory, "static");
   await Promise.all([
-    move(staticDirectory, opts.outputStaticDirectoryPath, { overwrite: true }),
-    moveResources(appDir, opts.outputDirectoryAppPath, opts.bundleYamlPath),
+    copy(staticDirectory, opts.outputStaticDirectoryPath, { overwrite: true }),
+    copyResources(appDir, opts.outputDirectoryAppPath, opts.bundleYamlPath),
     generateBundleYaml(opts, rootDir, nextVersion, adapterMetadata),
   ]);
   return;
 }
 
-// Move all files and directories to apphosting output directory.
+// Copy all files and directories to apphosting output directory.
 // Files are skipped if there is already a file with the same name in the output directory
-async function moveResources(
+async function copyResources(
   appDir: string,
   outputBundleAppDir: string,
   bundleYamlPath: string,
 ): Promise<void> {
   const appDirExists = await exists(appDir);
   if (!appDirExists) return;
-  const pathsToMove = await readdir(appDir);
-  for (const path of pathsToMove) {
+  const pathsToCopy = await readdir(appDir);
+  for (const path of pathsToCopy) {
     const isbundleYamlDir = join(appDir, path) === dirname(bundleYamlPath);
     const existsInOutputBundle = await exists(join(outputBundleAppDir, path));
     // Keep apphosting.yaml files in the root directory still, as later steps expect them to be there
     const isApphostingYaml = path === "apphosting_preprocessed" || path === "apphosting.yaml";
     if (!isbundleYamlDir && !existsInOutputBundle && !isApphostingYaml) {
-      await move(join(appDir, path), join(outputBundleAppDir, path));
+      await copy(join(appDir, path), join(outputBundleAppDir, path));
     }
   }
   return;