State you assumed would still be there
An auth token held in memory and a SQLite file on disk both worked locally and disappeared in production, because my laptop provides durability the serverless platform doesn't.
Debugging
7 notes filed here
Two background jobs that marked themselves done too early
Two background jobs stopped early and recorded themselves as complete, and once recorded, nothing in the system could reopen them.
The guard that only worked because something else was broken
Two defects were cancelling each other out. Fixing the real one on its own would have woken a dormant guard with the wrong logic and made the page worse.
A passing test that never saw the page
The tests for a desktop app's auto-scrolling passed the whole time the scrolling was broken: jsdom has no layout engine, so every height it reports is zero.
What stakeholder demos caught that our tests couldn't
Four kinds of failure our test suite couldn't see, which only surfaced once real stakeholders used an AI booking assistant in a room.
Three kinds of drift: currency, ghost flags and passenger types
A currency display bug, a feature flag that never existed in the flagging service, and a passenger type code nobody resolved: three kinds of drift that fail silently.