The December 16 bug
Today, I had planned to spend most of the day fixing a problem in TinderWin map views: resizing a note also changes its position.
But, instead, I found myself deep inside Tinderbox's date manipulation code. A test suite that ran yesterday mysteriously failed today. What had changed. The code was unchanged. The test was unchanged. But today was a new day. December 16.
And, as it happens, the code as written has a single >= where it ought to have had an =. The upshot is that an exception would be thrown in a test that adds 14 days to "today", if (and only if) the code were running on Windows and today was 16 December. If I'd taken the day off, if I'd been flying somewhere today, if I were working on Tinderbox 3.6 for Macintosh today, it's likely that nobody would have known until next year.
Update: The resize issue is fixed, too. There remain some map problems, of course, but ithe map's functionality is improving daily.