Tuesday, March 11, 2008

Solve the First Problem, and Don't Keep Going After It Breaks!

I cannot emphasize enough the truth and importance of Tilton's Law: Solve the First Problem:
Normally Tilton's Law refers to two or three observed issues that seem to be in the same ballpark. The law says pick out the one that seems most firstish and work on that and only that until it is solved. There is a terrific chance the other problems will just go away, and even if not the last thing we need to do while working on one problem is be looking over our shoulders at possible collateral damage from some other problem.
What I've experienced and expressed over my career is that once a bug has acted, you can no longer trust anything the software is doing. You've busted the state of the program, and everything that happens from that point on is suspect.

It drives me nuts when a tester has experienced a problem in the system being tested, logs it, and then keeps on going, writing error reports for every bit of collateral damage that is now cropping up. All of which have to be analyzed, dispositioned, and closed, and other than the first, none of which should have been written at all.

It's a waste of time, effort, and money for developers trying to uncover and fix bugs that are the after-effects of the "first" bug, or testers logging reports of the after-effects of a bug.

Report the first bug, fix the first bug, and move on.

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