Today, I found an error in the code library I am using. There was a header file that used an ostringstream object without including sstream. The code always compiled before because sstream always would get indirectly included by another file, but now I'm using it without the other classes that usually go with it. (Actually, I'll probably need some of them later, but I was trying to get a skeleton of a new class to compile today.) So, anyway, I added in a line to the header and committed it to the repository. I always feel a little odd when I do that, like I'm stepping on other people's toes, but in this case the change really did need to be made, and no one else had noticed it.