fix: createAssets fails in case of broken JSON in fetch cache (#963)

* fix: createAssets fails in case of broken JSON in fetch cache

* Add changeset

* Fix bump up from major to patch

* Log information about incorrectly parsed file

* Fix remarks to PR, adjust logging

* Fix code review remark

* Fix linting

Author: grabmateusz

.changeset/popular-tomatoes-jog.md

@@ -0,0 +1,5 @@
+---
+"@opennextjs/aws": patch
+---
+
+fix: createAssets fails in case of broken JSON in fetch cache

packages/open-next/src/build/createAssets.ts

@@ -2,6 +2,7 @@ import fs from "node:fs";
 import path from "node:path";
 
 import { loadConfig } from "config/util.js";
+import { safeParseJsonFile } from "utils/safe-json-parse.js";
 import logger from "../logger.js";
 import type { TagCacheMetaFile } from "../types/cache.js";
 import { isBinaryContentType } from "../utils/binary.js";
@@ -159,15 +160,20 @@ export function createCacheAssets(options: buildHelper.BuildOptions) {
   // Generate cache file
   Object.entries(cacheFilesPath).forEach(([cacheFilePath, files]) => {
     const cacheFileMeta = files.meta
-      ? JSON.parse(fs.readFileSync(files.meta, "utf8"))
+      ? safeParseJsonFile(fs.readFileSync(files.meta, "utf8"), cacheFilePath)
       : undefined;
+    const cacheJson = files.json
+      ? safeParseJsonFile(fs.readFileSync(files.json, "utf8"), cacheFilePath)
+      : undefined;
+    if ((files.meta && !cacheFileMeta) || (files.json && !cacheJson)) {
+      logger.warn(`Skipping invalid cache file: ${cacheFilePath}`);
+      return;
+    }
     const cacheFileContent = {
       type: files.body ? "route" : files.json ? "page" : "app",
       meta: cacheFileMeta,
       html: files.html ? fs.readFileSync(files.html, "utf8") : undefined,
-      json: files.json
-        ? JSON.parse(fs.readFileSync(files.json, "utf8"))
-        : undefined,
+      json: cacheJson,
       rsc: files.rsc ? fs.readFileSync(files.rsc, "utf8") : undefined,
       body: files.body
         ? fs
@@ -203,7 +209,7 @@ export function createCacheAssets(options: buildHelper.BuildOptions) {
       () => true,
       ({ absolutePath, relativePath }) => {
         const fileContent = fs.readFileSync(absolutePath, "utf8");
-        const fileData = JSON.parse(fileContent);
+        const fileData = safeParseJsonFile(fileContent, absolutePath);
         fileData?.tags?.forEach((tag: string) => {
           metaFiles.push({
             tag: { S: path.posix.join(buildId, tag) },
@@ -227,8 +233,8 @@ export function createCacheAssets(options: buildHelper.BuildOptions) {
           absolutePath.endsWith(".meta") && !isFileSkipped(relativePath),
         ({ absolutePath, relativePath }) => {
           const fileContent = fs.readFileSync(absolutePath, "utf8");
-          const fileData = JSON.parse(fileContent);
-          if (fileData.headers?.["x-next-cache-tags"]) {
+          const fileData = safeParseJsonFile(fileContent, absolutePath);
+          if (fileData?.headers?.["x-next-cache-tags"]) {
             fileData.headers["x-next-cache-tags"]
               .split(",")
               .forEach((tag: string) => {

packages/open-next/src/utils/safe-json-parse.ts

@@ -0,0 +1,16 @@
+import logger from "../logger.js";
+
+export function safeParseJsonFile<T = any>(
+  input: string,
+  filePath: string,
+  fallback?: T,
+): T | undefined {
+  try {
+    return JSON.parse(input);
+  } catch (err) {
+    logger.warn(
+      `Failed to parse JSON file "${filePath}". Error: ${(err as Error).message}`,
+    );
+    return fallback;
+  }
+}