land-complex-change
Land a complex change
A complex change rarely fails at the part that was planned. It fails at the edges: the file that got tidied because it was already open, the guard that has been green since the day it was written and could never have failed, the migration that got applied because applying it was the obvious next step, the second consumer nobody mapped. The diff is reviewable and the review still misses these, because a reviewer sees what changed — not what was allowed to change, and not which of the green checks were ever capable of turning red.
Two costs, named apart because different mechanics prevent them. A side effect is work the change did that nobody declared. A regression is behaviour that used to hold, does not any more, and had nothing watching it. This skill contains the first with a budget and catches the second with a gate per affected surface — and when the work turns out to be bigger than the map said, it stops rather than absorbing the difference quietly.
It changes the repository. Everything it changes was declared first.