Fix error interceptors not being called for network failures

[Copilot]

Error interceptors in the custom client were not being triggered when network-level failures occurred (CORS errors, DNS failures, connection timeouts, etc.). This meant that developers' error handling and logging code was completely bypassed for some of the most common request failure scenarios.

Problem demonstrated:

const client = createClient({
  baseUrl: 'https://invalid-domain.com', // Will cause network error
});

client.interceptors.error.use((error, response) => {
  console.log('This should be called but wasn\'t!');
  return error;
});

// Before fix: interceptor never called for network errors
await client.get({ url: '/test' });

Root cause:
The fetch() call was not wrapped in a try-catch block, so network exceptions bypassed the error interceptor logic entirely. Only HTTP response errors (4xx, 5xx status codes) were being handled.

Solution:

• Wrapped the fetch call in try-catch to capture network-level errors
• Updated the ErrInterceptor type signature to accept response: Res | undefined since network errors don't have a response object
• When network errors occur, error interceptors are called with undefined as the response parameter
• Maintained full backward compatibility for existing HTTP response error handling

After fix:

// Network errors now properly trigger interceptors
client.interceptors.error.use((error, response) => {
  if (response) {
    console.log('HTTP error:', response.status);
  } else {
    console.log('Network error:', error.message); // Now called!
  }
  return error;
});

This makes error interceptors a reliable tool for handling all types of request failures, improving debugging capabilities and making the client behavior more predictable.

Fixes #1994.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• messedupbaseurl
  • Triggering command: node /tmp/demo-fix-1994.js (dns block)
• nonexistent-domain-12345.com
  • Triggering command: node /tmp/test-error-interceptors.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

---

💡 You can make Copilot smarter by setting up custom instructions, customizing its development environment and configuring Model Context Protocol (MCP) servers. Learn more Copilot coding agent tips in the docs.

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Project	Deployment	Preview	Comments	Updated (UTC)
hey-api-docs	Ready	Preview	Comment	Sep 18, 2025 11:44am

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