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Code RoomFan-out query goroutine resource leak
HardPrep Room Coding #4140

Fan-out query goroutine resource leak

Vibe & agenticAlgorithms & data structuresSenior–Staff~20 min

An AI wrote this Go fan-out helper that queries N replicas and returns the first response. It compiles and the happy path works. Review it for cancellation and leaks.

What resource problem does this have, and how do you fix it?

Implement
count_leaked_goroutines(latency_ms: list[int], succeeded: list[bool], timeout_ms: int, buffer_capacity: int, cancel_losers: bool) → int
Examples
in[[10,20,30],[true,true,true],1000,0,false]out2
in[[10,20,30],[true,true,true],1000,3,false]out0
in[[10,20,30],[true,true,true],1000,0,true]out0
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.

0:00 of about 20 min

Vibe & agentic: describe the solution in plain language (or narrate it) and the coach grades your approach.

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.