One of my leisure time activities is to develop KMyMoney, a personal finance management application. Most of my time is spent on development, testing, bug reproduction and fixing, user support and sometimes I even write some documentation for this application. And of course, I use it myself on a more or less daily basis.
One of the nice KMyMoney features that helps me a lot is the online transaction download. It’s cool, if you simply fire up your computer in the morning, start KMyMoney, select the “Account/Update all” function, fill in the passwords to your bank and Paypal accounts when asked (though also that is mostly automated using a local GPG protected password store) and see the data coming in. After about a minute I have an overview what happened in the last 24 hours on my accounts. No paper statement needed, so one could say, heavily digitalized. At this point, many thanks go out to the author of AqBanking which does all the heavy work dealing with bank’s protocols under the hood. But a picture is worth a thousand words. See for yourself how this looks like:
The process is working for a long time and I have not touched any of the software parts lately. Today, I noticed a strange thing happening because one of my accounts showed me a difference between the account balance on file and the amount provided by the bank after a download. This may happen, if you enter transactions manually but since I only download them from the bank, there should not be any difference at all. Plus, today is Sunday while on the day before everything was just fine. First thought: which corner case did I hit that KMyMoney is behaving this way and where is the bug?
First thing I usually do in this case is to just close the application and start afresh. No way: same result. Then I remembered, that I added a feature the day before to the QIF importer which also included a small change in the general statement reader code. Of course, I tested things with the QIF importer but not with AqBanking. Maybe, some error creeped into the code and causes this problem. I double checked the code and since it dealt with tags – which are certainly not provided by my bank – it could not be the cause of it.
So I looked at the screen again:
New data must have been received because the date in the left column changed and also the amount of the colored row changed but not the one in the row above which still shows the previous state. The color is determined by comparing the balance information with the one in the row above. So where is/where are the missing transaction(s)?
Long story short: looking at the logs I noticed, that the online balance was transmitted but there was no transaction at all submitted by the bank. And if I simply take the difference between the two balances it comes down to a reimbursement payment which I expect to receive.
Conclusion: no bug in KMyMoney, but the bank simply provided inconsistent data. Arrrrgh.