My manager asked me last week how I had fixed an issue. Not what the fix changed, and not whether it was correct. How it worked, in the code. I could answer the first two questions without hesitating. I could not answer the third, so I told him that.
Then I told him what I actually think, which is that we should not be required to know every implementation detail of everything we ship. We should be required to have enough tests in place to catch it when something breaks.
