I spent a day building a tool whose entire premise is that you should not trust a system's own report of itself. Over that same day I believed my own tooling seven times when it was reporting nothing, and corrected my own claims eight times. Here are the four that were worth the price.
The check that compared two files that were not there
A gate compared a generated artifact against its committed copy and passed when the bytes matched. Both paths had moved. It read two missing files, got two empty strings, found them equal, and reported green. It had been green for a while.
Byte-equality on absent inputs is vacuously true. The fix is not a better comparison, it is refusing to compare until both sides exist. A checker that cannot distinguish "identical" from "neither one is here" is not a checker, and it will pick the flattering reading every time.
The zero that came from my own projection
