Is there a reason why *all* bug fixes are not accompanied by one or more new test cases that demonstrate the presence and absence of the bug before and after the fix? Adding such test cases should be mandatory for all bug fix commits. I wouldn't quite go that far for performance and clean up fixes, however, but for legitimate bugs, there should be a reliable way to ensure that (1) the bug and its fix are testable and (2) that future regressions do not occur. I realize it takes more effort, but it is worth it in the long term, both in actual improvements in quality and the ability to demonstrate consistently good practice to maintain that quality.
Many Apache projects require this process be followed; I would urge the FOP project to adopt a similar criterion for bug fix commits. G.