Fixing Next.js 15.4.3 Build Errors A Guide For Kurikara-dev Zubari

July 25, 2025 by StackCamp Team 67 views

Troubleshooting Next.js 15.4.3 Build Errors A Detailed Guide

Hey guys! Building a Next.js application can sometimes feel like navigating a maze, especially when you hit those dreaded build errors. Today, we’re going to dive deep into troubleshooting a specific build error encountered in a Next.js 15.4.3 project, Kurikara-dev/zubari. We'll break down the error logs, identify the root causes, and provide actionable solutions to get your build back on track. So, grab your favorite beverage, and let's get started!

Understanding the Build Environment

Before we jump into the errors, let's understand the environment where the build is happening. The logs indicate that the build is running on Vercel in Washington, D.C., using a machine with 2 cores and 8 GB of memory. This information is crucial because resource constraints or platform-specific issues can sometimes contribute to build failures. Vercel CLI version 44.5.0 is being used, and the project is being built from the main branch of the Kurikara-dev/zubari repository.

[09:21:16.014] Running build in Washington, D.C., USA (East) – iad1
[09:21:16.014] Build machine configuration: 2 cores, 8 GB
[09:21:16.032] Cloning github.com/Kurikara-dev/zubari (Branch: main, Commit: 3235edc)
[09:21:16.312] Cloning completed: 280.000ms
[09:21:18.680] Restored build cache from previous deployment (3BbS2CaU51ttd4h55WNxTTmWieZe)
[09:21:19.329] Running "vercel build"
[09:21:20.385] Vercel CLI 44.5.0
[09:21:21.349] Running "install" command: `npm install`...

Initial Setup and Dependency Installation

The build process starts with cloning the repository and restoring the build cache from a previous deployment. This is a common optimization to speed up build times. The npm install command then runs, which installs all the project dependencies. Let’s highlight some key points here:

Cloning and Caching: The repository is cloned, and the build cache is restored. This speeds up the build process by reusing previously built artifacts.
Dependency Installation: npm install installs all the necessary packages. Deprecated packages are flagged, which is something to keep an eye on, though not necessarily the cause of the immediate build failure.
Warnings: Keep an eye on deprecated packages! While they might not be the root cause right now, they could cause issues down the line. Think of it as future-proofing your project.

npm warn deprecated glob@7.2.3: Glob versions prior to v9 are no longer supported
npm warn deprecated sourcemap-codec@1.4.8: Please use @jridgewell/sourcemap-codec instead
npm warn deprecated inflight@1.0.6: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.
added 403 packages, and audited 786 packages in 6s
192 packages are looking for funding
  run `npm fund` for details
found 0 vulnerabilities

Health Check and Project Analysis

The next crucial step is the health check. The project runs a custom script, scripts/health-check.js, which performs various checks, including circular dependencies, TypeScript configuration, technical debt, build system validation, project scale, and security. This is an excellent practice to ensure the project's overall health and identify potential issues early on.

Quick Health Check: This includes checking for circular dependencies and TypeScript configuration. These are vital for ensuring the project's architecture is sound and type safety is maintained.
Comprehensive Health Check: This delves deeper, validating the build system, assessing project scale (number of files and lines of code), and performing a basic security check.
Warnings: A low technical debt score (49/100) is flagged. Technical debt refers to the implied cost of rework caused by choosing an easy solution now instead of using a better approach that would take longer. While not a build error, it's a strong indicator that the codebase might benefit from some refactoring. Ignoring this could lead to more significant issues in the future.

> zubari@0.1.0 health:full
> node scripts/health-check.js --full

ℹ️  [00:21:28] Running quick health check...
ℹ️  [00:21:28] Checking circular dependencies...
✅ [00:21:28] No circular dependencies detected
ℹ️  [00:21:28] Type checking critical files...
✅ [00:21:28] TypeScript configuration found
⚠️  [00:21:29] Technical debt score low: 49/100
ℹ️  [00:21:29] Running comprehensive health check...
ℹ️  [00:21:29] Validating build system...
✅ [00:21:29] Build system validation passed
ℹ️  [00:21:29] Project scale: 99 files, 9779 lines
ℹ️  [00:21:29] Running security health check...
✅ [00:21:29] Basic security check passed

==================================================
ℹ️  [00:21:29] Health check completed in 995ms
⚠️  [00:21:29] ⚠️  Project health: WARNING
Warnings:
  - Technical debt score: 49/100

Scores:
  technicalDebt: 49
  fileCount: 99
  lineCount: 9779

Identifying the Compilation Errors

Now, let's get to the heart of the issue: the compilation errors. After the health check, Next.js starts building the application. The build process includes linting and type checking, which are crucial for catching errors before deployment. This is where the build fails.

▲ Next.js 15.4.3
   - Experiments (use with caution):
     ✓ optimizeCss
     · webVitalsAttribution
     · optimizePackageImports

 Creating an optimized production build ...
✓ Compiled successfully in 17.0s
   Linting and checking validity of types ...

Failed to compile.

./src/app/api/media/paginated/route.ts
23:11  Warning: '_session' is assigned a value but never used.  @typescript-eslint/no-unused-vars

./src/components/media/FilterSelector.tsx
49:10  Warning: '_activeGroup' is assigned a value but never used.  @typescript-eslint/no-unused-vars

./src/components/media/ImageFilters.tsx
43:14  Warning: '_projectId' is defined but never used.  @typescript-eslint/no-unused-vars

...

./src/components/projects/ProjectList.tsx
118:13  Error: Do not use an `<a>` element to navigate to `/projects/new/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages  @next/next/no-html-link-for-pages

...

Error: Command "npm run build" exited with 1

The error log shows a mix of warnings and a critical error. Let's break them down:

TypeScript and ESLint Warnings

There are numerous warnings related to unused variables (@typescript-eslint/no-unused-vars) and missing dependencies in React Hooks (react-hooks/exhaustive-deps). While these warnings don't directly cause the build to fail, they indicate potential code quality issues. Ignoring these warnings can lead to bugs and performance problems down the line.

Unused Variables: These warnings flag variables that are declared but never used. This often indicates dead code or missed opportunities for optimization.
Missing Hook Dependencies: These warnings are crucial. The react-hooks/exhaustive-deps rule ensures that your React Hooks have all the necessary dependencies specified in their dependency arrays. Missing dependencies can lead to stale closures and unexpected behavior.

Critical Error: `next/link`

The showstopper is this error:

./src/components/projects/ProjectList.tsx
118:13  Error: Do not use an `<a>` element to navigate to `/projects/new/`. Use `<Link />` from `next/link` instead. See: https://nextjs.org/docs/messages/no-html-link-for-pages  @next/next/no-html-link-for-pages

This error clearly states that you should use the <Link /> component from next/link for internal navigation within a Next.js application, instead of a standard HTML <a> tag. This is a fundamental requirement in Next.js for proper routing and performance optimizations.

Diagnosing the Root Cause

Okay, so we know the error. But why is it happening? Let's dig a little deeper:

Incorrect Navigation: The primary cause is the use of an HTML <a> tag for internal navigation. Next.js uses its own routing system, and <Link /> is designed to work seamlessly with it. Using <a> tags bypasses this system, leading to potential issues with client-side routing and prefetching.
Linting Configuration: The warnings suggest that the project's ESLint configuration might not be strict enough. While warnings don't break the build by default, it's good practice to treat them as errors in development to enforce code quality.
Technical Debt: The low technical debt score hints at potential architectural or code quality issues that could contribute to errors like this. A cleaner codebase is generally easier to maintain and less prone to errors.

Actionable Solutions

Alright, time to fix this! Here’s a step-by-step guide to resolving the build error and addressing the warnings:

1. Replace `<a>` with `<Link />`

This is the most critical fix. In src/components/projects/ProjectList.tsx, replace the HTML <a> tag with the <Link /> component from next/link:

// Before
<a href="/projects/new/">Create New Project</a>

// After
import Link from 'next/link';

<Link href="/projects/new/">Create New Project</Link>

This ensures that Next.js handles the navigation correctly.

2. Address TypeScript and ESLint Warnings

While not immediately causing the build failure, these warnings indicate potential issues. Let's tackle them:

Unused Variables: Remove the unused variables or, if they are intentionally unused (e.g., for future use), prefix them with an underscore (e.g., _session) to silence the warning.
```
// Before
const _session = useSession();

// After
const session = useSession(); // If used

// OR

const _session = useSession(); // If intentionally unused
```
Missing Hook Dependencies: Carefully review the dependencies for each useCallback and useEffect Hook. Add any missing dependencies to the dependency array. If a dependency is expensive to compute or causes infinite loops, consider using useRef or other optimization techniques.
```
// Before
const handleClick = useCallback(() => {
  // ...
}, []); // Missing dependencies

// After
const handleClick = useCallback(() => {
  // ...
}, [dependency1, dependency2]); // Dependencies added
```

3. Strengthen ESLint Configuration (Optional but Recommended)

To prevent similar issues in the future, consider strengthening your ESLint configuration. You can configure ESLint to treat warnings as errors during the build process. This forces you to address warnings before merging code, leading to a cleaner codebase.

Modify next.config.js: Add the eslint configuration to your next.config.js file:
```
// next.config.js
module.exports = {
  eslint: {
    ignoreDuringBuilds: true,
  },
};
```
Setting ignoreDuringBuilds to true prevents ESLint from running during the build process. This might seem counterintuitive, but it allows you to focus on fixing the core error first. Once the build is successful, you can remove this and address the ESLint warnings more thoroughly.
Adjust ESLint Rules: Review your .eslintrc.js or .eslintrc.json file and adjust the rules to be more strict. For example, you can change the severity of the @typescript-eslint/no-unused-vars rule to `