Two switches on the same enum drifted in my #Flutter app, and the screen ended up contradicting itself. The card said "practice done" while the button right under it still opened the flashcards. Here's what happened, and how Dart 3 made it impossible to repeat. The server returns a word's progress status. The client derives two things from it: the label on the CTA, and where that CTA navigates. I wrote those as two separate switches, in two different files. They agreed the day I wrote them. Then I added a status, updated one, forgot the other. Nothing failed. No exception, no warning. Just a widget saying two opposite things to the same user. The fix wasn't better discipline. It was removing the possibility. The status now produces a single value, and both the label and the destination derive from it. Because a Dart 3 switch expression over an enum is exhaustive, adding a status tomorrow is a compile error at every site that derives anything from it, not a screen contradicting itself six weeks later. I also moved the label onto the enum rather than the widget. The copy travels with the value, so a new screen showing this step can't invent its own wording. Small thing. But it's the difference between a bug I catch and a bug my users catch. #FlutterDev #Dart #BuildInPublic #Shipaton

I shipped my vocabulary app Wordhabit a few days ago. Yesterday I measured the onboarding for the first time. 81 people started. 15 finished. Here's where the other 66 went 🧵 #Dart #Flutter #BuildInPublic #shipaton