I think you have to give up on the idea that you can fix ALL bugs all the time. But I don't think we need to be defeatist. Each layer of tests is an improveme

I think you have to give up on the idea that you can fix ALL bugs all the time. But I don't think we need to be defeatist. Each layer of tests is an improvement. The benefits of unit testing, integration testing, comparison testing, and fuzz testing are pretty unambiguous. We can always add more layers that give us high assurances against certain classes of bugs. Do we have systems to write programs that are free of dangling pointers? Yes. Double frees? Yes. Buffer overflows? Yes. Seg faults? Yes. With regard to infinite loops, we cannot prove programs in general terminate or not, but we CAN prove that some programs terminate. If our program cannot be proven, we can adjust it until it can. I guess this is similar to theorem proving. We have to be able to define what kind of bug we're talking about, and develop in a system that allows us to prove to ourselves that we no longer have that class of bug. When I talk about a "system", I don't care what it is. Maybe it's a library or set of functions or API that doesn't allow for certain types of errors. Maybe it's a static analysis tool. Maybe it's a language. It doesn't matter, as long as you can have high assurances later that your large code base no longer contains a particular class of errors. Does this get rid of all bugs? No, but it greatly reduces the possible ways that bugs can exist, and that's huge progress.