fix: adding a null pointer check for error.stack

[vdua]

• error.stack is not a standard api

Please ensure your pull request adheres to the following guidelines:

• make sure to link the related issues in this description
• when merging / squashing, make sure the fixed issue references are visible in the commits, for easy compilation of release notes

Related Issues

Thanks for contributing!

Test URL

https://fix-error-stack--helix-rum-js--adobe.aem.live/test/static.html

[aem-code-sync]

Hello, I'm the AEM Code Sync Bot and I will run some actions to deploy your branch and validate page speed.
In case there are problems, just click a checkbox below to rerun the respective action.

• Re-run PSI checks
• Re-sync branch

Commits

• b7c9a64 ✅ (latest)

[adobe-bot]

Claude finished @vdua's task —— View job

---

Code Review Complete ✅

I've reviewed this PR for code quality, potential bugs, performance considerations, security concerns, and test coverage.

Todo List:

• Read repository guidelines (CLAUDE.md)
• Analyze the code changes in src/index.js
• Review for code quality and best practices
• Check for potential bugs or issues
• Assess performance considerations
• Evaluate security concerns
• Review test coverage needs
• Provide comprehensive feedback

---

Review Feedback

✅ Positive Changes

Core Fix is Solid: The null check for error.stack at src/index.js:35 is a good defensive programming practice. Since error.stack is not standardized across all JavaScript environments, this prevents runtime errors when the property is undefined.

Proper Error Handling: The fix maintains the existing try-catch structure and gracefully handles cases where error.stack is not available.

🚨 Critical Issues

1. Unintended Content Addition (HIGH SEVERITY)
The PR accidentally adds 24 lines of unrelated documentation content (lines 113-134) that appears to be about "Coding Agent" functionality. This content:

• Has no relation to the error.stack fix
• Contains incomplete text that cuts off mid-sentence
• Should be completely removed from this PR

2. Logic Issue in Stack Processing (MEDIUM SEVERITY)
At src/index.js:36-40, the code calls .shift() on the filtered array, but .shift() returns undefined if the array is empty. This could lead to:

errData.source = error.stack.split('\n')
    .filter((line) => line.match(/https?:\/\//)).shift() // Could be undefined
    .replace(/at ([^ ]+) \((.+)\)/, '$1@$2') // TypeError if undefined

Recommendation: Add a null check after .shift():

if (error.stack) {
  const stackLine = error.stack.split('\n')
      .filter((line) => line.match(/https?:\/\//)).shift();
  if (stackLine) {
    errData.source = stackLine
        .replace(/at ([^ ]+) \((.+)\)/, '$1@$2')
        .replace(/ at /, '@')
        .trim();
  }
}

📋 Code Quality & Best Practices

Indentation Inconsistency: The added if (error.stack) block uses 2 extra spaces of indentation compared to the original code style. Consider aligning with the existing 2-space indentation pattern.

🔒 Security Assessment

No Security Concerns: The changes don't introduce any security vulnerabilities. The error handling is defensive and doesn't expose sensitive information.

⚡ Performance Considerations

Minimal Performance Impact: The added null check is a simple boolean operation with negligible performance overhead. The fix actually prevents potential performance issues from runtime errors.

🧪 Test Coverage Assessment

Current Test Coverage: The existing test suite in /test/errors/ appears comprehensive with tests for various error scenarios.

Missing Test Case: Consider adding a test case for errors without a stack property to verify the new null check works correctly:

it('rum capture error without stack property', async () => {
  await test(() => {
    const errorWithoutStack = new Error('No stack');
    delete errorWithoutStack.stack; // Remove stack property
    throw errorWithoutStack;
  }, (source) => {
    assert.strictEqual(source, 'undefined error'); // Should fallback to default
  }, (target) => {
    assert.strictEqual(target, 'Error: No stack');
  }, config.queue);
});

🔧 Recommended Actions

1. MUST FIX: Remove lines 113-134 (unrelated documentation content)
2. SHOULD FIX: Add null check after .shift() to prevent potential TypeError
3. CONSIDER: Add test case for error objects without stack property
4. MINOR: Adjust indentation to match existing code style

---

[aem-code-sync]

	Page	Scores	Audits	Google
📱	/test/static.html
🖥️	/test/static.html