Prep Room
Sign inCreate account
Code Room
Vibe codingMediumvc-g496
Subject Ai code reviewLevel Mid~14 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

An AI wrote this helper used by a FastAPI service to accumulate request tags before saving. QA reports that tags from one user's request mysteriously show up on a later, unrelated user's request. Find the bug.

python
def build_event(name: str, tags: list = []):    tags.append(f"event:{name}")    return {"name": name, "tags": tags, "ts": time.time()} @app.post("/track/{name}")async def track(name: str):    event = build_event(name)    return event
What a strong answer looks like

Treat the AI’s output as a draft to verify, not an answer to trust. Name the specific flaw and the input that triggers it, say how you’d catch it — tests, edge cases, reading critically — and how you’d re-prompt or decompose to get it right.

Learn the concepts
Describe your solution

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.