Time: 0:00
Test a custom input to verify an edge case (e.g. empty lists, negative numbers, duplicates).
This bug belongs to the null and undefined errors pattern
Cannot read properties of undefined, NoneType has no attribute, NaN appearing from nowhere.
What went wrong: user["middle"] crashes when the key is missing, and + crashes when the value is None.
The fix: parts = [user.get("first"), user.get("middle"), user.get("last")] and return " ".join(p for p in parts if p)
Remember: for optional values, gather what exists and skip the rest.
The pattern behind it: null and undefined errors.
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<iframe src="https://trybughunt.com/embed/6405a8a8-f3dc-4cd5-8dbe-ba7282561eca" title="Debugging challenge: Full name crashes when there is no middle name" width="100%" height="580" loading="lazy" style="border:1px solid #d4d4d8;border-radius:12px;max-width:760px"></iframe>
<p style="font-size:14px">Debugging challenge from <a href="https://trybughunt.com/challenges/6405a8a8-f3dc-4cd5-8dbe-ba7282561eca">TryBugHunt</a></p>