Skipping partial html files generated due to enabling ppr in Nextjs

src/frameworks/next/index.ts

@@ -97,13 +97,13 @@
 const DEFAULT_NUMBER_OF_REASONS_TO_LIST = 5;
 
 function getReactVersion(cwd: string): string | undefined {
   return findDependency("react-dom", { cwd, omitDev: false })?.version;
 }
 
 /**
  * Returns whether this codebase is a Next.js backend.
  */
 export async function discover(dir: string) {
   if (!(await pathExists(join(dir, "package.json")))) return;
   const version = getNextVersion(dir);
   if (!(await whichNextConfigFile(dir)) && !version) return;
@@ -160,10 +160,10 @@
 
   const nextBuild = new Promise((resolve, reject) => {
     const buildProcess = spawn(cli, ["build"], { cwd: dir, env });
     buildProcess.stdout?.on("data", (data) => logger.info(data.toString()));
     buildProcess.stderr?.on("data", (data) => logger.info(data.toString()));
     buildProcess.on("error", (err) => {
       reject(new FirebaseError(`Unable to build your Next.js app: ${err}`));
     });
     buildProcess.on("exit", (code) => {
       resolve(code);
@@ -536,6 +536,15 @@
       let defaultDestPath = isDefaultLocale && join(destDir, basePath, ...destPartsOrIndex);
       if (!fileExistsSync(sourcePath) && fileExistsSync(`${sourcePath}.html`)) {
         sourcePath += ".html";
+        // Check if the HTML file is partial (doesn't have closing </html> tag)
+        const content = await readFile(sourcePath, "utf8");
+        if (!content.includes("</html>")) {
+          logger.debug(
+            `Skipping ${path} as it appears to be a partial HTML file which is not supported by Firebase Hosting`,
+          );
+          return;
+        }
+
         if (localizedDestPath) localizedDestPath += ".html";
         if (defaultDestPath) defaultDestPath += ".html";
       } else if (