Once I had a situation where I was the developer assigned to a particular interface and my code was synonymous with the code. Unbeknownst to me, a defect was e

Once I had a situation where I was the developer assigned to a particular interface and my code was synonymous with the code. Unbeknownst to me, a defect was entered and another programmer made a change. It wasn't really a bugfix but more like a change in the desired functionality. His change worked perfectly well but I wasn't made aware that someone else had changed the code. When I was assigned another defect, I used the version of the code that I had from my last checkout to make the change. When I checked in, I overwrote his change. We quickly discovered this during testing and I reverted my change. I used his last checked in code as the basis for my change and all was right with the world but we had a confused user and two confused programmers for a couple of hours.