Fix Next.js 16 Build Error In Nx Monorepo

by Alex Johnson 42 views

Experiencing build failures after upgrading to Next.js 16 in an Nx monorepo can be frustrating. One common error, "Cannot destructure property 'resolver' of 'pending.get(...)' as it is undefined," often surfaces during production builds. This comprehensive guide will walk you through the issue, its causes, and provide step-by-step solutions to get your builds running smoothly again.

Understanding the Issue

The error message TypeError: Cannot destructure property 'resolver' of 'pending.get(...)' as it is undefined indicates a problem during the project graph creation within the Nx build process. This typically happens when Next.js 16 encounters an unexpected state while resolving dependencies or processing project configurations. It's crucial to understand that this error usually doesn't appear in development mode, making it trickier to debug.

Key symptoms of this issue include:

  • Successful development server execution (nx serve <MY_APP_NAME>).
  • Build failures only during production builds (nx build <MY_APP_NAME>).
  • The error occurring after upgrading from Next.js 15.4.6 to Next.js 16.0.3 or later.
  • A full build output showing the error message and a subsequent "Error: Could not create project graph" message.

Diving Deeper into the Root Causes

Several factors can contribute to this error. Identifying the root cause is the first step towards resolving the issue. Here are some common culprits:

  1. Incompatible Dependencies: Upgrading Next.js might introduce compatibility issues with other dependencies in your monorepo, particularly Nx plugins, Material UI, Emotion, or other third-party libraries. Ensure that all your dependencies are compatible with Next.js 16.
  2. Nx Configuration Issues: Misconfigurations in your nx.json or project-specific project.json files can disrupt the project graph creation process. Incorrect paths, missing dependencies, or conflicting settings can all lead to build failures.
  3. Webpack Configuration Problems: Next.js relies on Webpack for bundling and optimization. Custom Webpack configurations or conflicts with existing plugins can sometimes cause unexpected errors during the build process.
  4. TypeScript Issues: Type mismatches or errors in your TypeScript code can sometimes manifest during the production build, especially if you're using stricter TypeScript settings.
  5. Cache Invalidation: Sometimes, stale cache data can interfere with the build process. Clearing the Nx and Next.js caches can often resolve transient issues.

Step-by-Step Solutions to Resolve the Build Failure

Now that we understand the potential causes, let's explore the solutions. Follow these steps in order to systematically troubleshoot and resolve the "Cannot destructure property 'resolver'" error.

1. Verify Next.js and Nx Plugin Versions

Start by ensuring that you're using compatible versions of Next.js and the @nx/next plugin. Check the official Nx compatibility matrix or release notes to identify the recommended versions. If there's a mismatch, upgrade or downgrade the relevant packages.

npm install next@latest @nx/next@latest

2. Review Your nx.json Configuration

The nx.json file is the heart of your Nx monorepo configuration. Carefully review it for any misconfigurations or inconsistencies. Pay close attention to:

  • projects: Ensure that all your projects are correctly listed and that the paths are accurate.
  • plugins: Verify that all necessary Nx plugins are included and that their configurations are correct.
  • affected: Check if any changes to the affected settings might be impacting the build process.

3. Examine Project-Specific project.json Files

Each Next.js application in your monorepo has a project.json file that defines its build and serve targets. Scrutinize these files for any errors. Key areas to check include:

  • targets.build.executor: Make sure it's set to @nx/next:build.
  • targets.build.outputs: Verify that the output paths are correctly configured.
  • targets.build.configurations: Ensure that the production configuration is properly defined.
  • dependencies: Check for any missing or conflicting dependencies.

Here’s an example of a project.json configuration:

{
    "name": "<MY_APP_NAME>",
    "$schema": "../../node_modules/nx/schemas/project-schema.json",
    "sourceRoot": "apps/<MY_APP_NAME>",
    "projectType": "application",
    "targets": {
        "build": {
            "executor": "@nx/next:build",
            "outputs": ["{options.outputPath}"],
            "defaultConfiguration": "production",
            "options": {
                "outputPath": "dist/apps/<MY_APP_NAME>"
            },
            "configurations": {
                "development": {
                    "outputPath": "apps/<MY_APP_NAME>"
                },
                "production": {}
            }
        },
        "serve": {
            "executor": "@nx/next:server",
            "defaultConfiguration": "development",
            "options": {
                "buildTarget": "<MY_APP_NAME>:build",
                "dev": true,
                "port": 443,
                "hostname": "local.<MY_APP_NAME>.com",
                "experimentalHttps": true
            },
            "configurations": {
                "development": {
                    "buildTarget": "<MY_APP_NAME>:build:development",
                    "dev": true
                },
                "production": {
                    "buildTarget": "<MY_APP_NAME>:build:production",
                    "dev": false
                }
            }
        },
        "export": {
            "executor": "@nx/next:export",
            "options": {
                "buildTarget": "<MY_APP_NAME>:build:production"
            }
        }
    }
}

4. Resolve Dependency Conflicts

Dependency conflicts are a common cause of build failures. Use your package manager's tools to identify and resolve any conflicts. For npm, you can use npm ls to list installed packages and their dependencies. For yarn, use yarn why <package-name> to find out why a specific package is installed.

5. Clear Caches

Stale caches can sometimes lead to unexpected errors. Clear the Nx and Next.js caches to ensure a clean build.

nx reset
npm run <MY_APP_NAME>:build -- --clearCache

6. Temporarily Remove Custom Webpack Configurations

If you're using custom Webpack configurations, they might be interfering with the Next.js build process. Try temporarily removing your custom configurations to see if the issue resolves. If it does, you'll need to carefully review your Webpack configuration for compatibility issues.

7. Check TypeScript Configuration

TypeScript errors can sometimes manifest during production builds. Ensure that your TypeScript configuration (tsconfig.json) is correct and that there are no type errors in your code. Running tsc --noEmit can help identify TypeScript errors.

8. Review Third-Party Dependencies

Third-party libraries, especially UI libraries like Material UI and Emotion, can sometimes cause conflicts with Next.js. Ensure that you're using compatible versions of these libraries and that their configurations are correct. If you're using Material UI, pay attention to the @mui/material-nextjs package, which helps with server-side rendering.

9. Create a Minimal Reproduction

If none of the above steps resolve the issue, try creating a minimal reproduction of the problem. This involves creating a new Nx monorepo with a simplified Next.js application that exhibits the same error. Sharing this reproduction with the Nx community or the library maintainers can help them identify and fix the issue.

Example: Resolving Material UI and Emotion Compatibility Issues

One common scenario involves compatibility issues between Material UI, Emotion, and Next.js. If you're using these libraries, ensure that you have the correct versions and configurations.

  1. Install @mui/material-nextjs:

    npm install @mui/material-nextjs

  2. Configure Emotion Cache:

    Create a src/utils/createEmotionCache.ts file:

    import createCache from '@emotion/cache';

export default function createEmotionCache() {
  return createCache({ key: 'css', prepend: true });
}

  3. Wrap Your Application with MuiCacheProvider:

    In your _app.tsx or _app.js file:

    import React from 'react';
import { MuiCacheProvider } from '@mui/material-nextjs/v13-pagesRouter';
import createEmotionCache from '../utils/createEmotionCache';

const emotionCache = createEmotionCache();

function MyApp({ Component, pageProps }: any) {
  return (
    <MuiCacheProvider prefixKey="app" emotionCache={emotionCache}>
      <Component {...pageProps} />
    </MuiCacheProvider>
  );
}

export default MyApp;

Conclusion

The "Cannot destructure property 'resolver'" error in Next.js 16 within an Nx monorepo can be a challenging issue to resolve. However, by systematically troubleshooting and following the steps outlined in this guide, you can identify the root cause and get your builds back on track. Remember to verify dependencies, review configurations, clear caches, and consider third-party library compatibility. By addressing these potential issues, you'll be well-equipped to tackle this error and ensure a smooth development and build process.

For more in-depth information and community support, consider visiting the official **Nx documentation **.