Another stupid mistake has taken a lot of my time last week. I developed a small library to provide function(s) to move attachments from rich text fields to separate db (nsf or some other). This function was supposed to be part of bigger process, so saving of document being processed was meant to happen in other code. That is why I had not tested what doc.save() would do. My tests were just checking destination db for created records containing moved files.

Recently friend of mine asked me for help with an XPages application and one of the "problems" we had was validating user inputs.
We needed to make sure that user enters something in one of the two fields. My first thought was "ok, it's going to be a simple xp:validateExpression checking for non empty string and returning true". But after giving it one more thought, I ended up with "just make one of the fields required, if the other one is empty"