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Code RoomRolling deploy column rename breaks
HardPrep Room Coding #4063

Rolling deploy column rename breaks

Vibe & agenticAlgorithms & data structuresSenior–Staff~18 min

An AI agent was asked to rename the `users.fullname` column to `users.full_name` for consistency. It produced a single migration and a code change in the same PR. The PR merged; during the rolling deploy, production threw a burst of 500s before stabilizing.

Why did the rolling deploy break, and what's the safe sequence?

Implement
first_unsafe_step(initial_columns: list[str], initial_code: str, steps: list[str]) → int
Examples
in[["id","fullname"],"id,fullname",["migrate:fullname>full_name","deploy:id,full_name"]]out1
in[["id","fullname"],"id,fullname",["migrate:+full_name","deploy:id,fullname,full_name","deploy:id,full_name","migrate:-fullname"]]out0
in[["id","fullname"],"id,fullname",["deploy:id,full_name"]]out1
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 18 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.