Thanks! I'll extend it a little bit.
This issue looks good to merge, and probably should be merged if we refer to the
class it introduces in our coding conventions. :-) I didn't realize this was not
merged yet, sorry to keep you waiting.
Jendrik, is it worth saying something about exceptions on our coding conventions
page? This is one of these things where there are many different ways of
approaching things, and it would be good to stay consistent.
I also had a look. Jendrik and I talked about our strategy for defining our own
exceptions more generally on bitbucket, and the pull request will go through
another iteration.
I had a quick look at the PR and it looks good to me. However, I haven't checked
if the printed error messages look good; did you? Does it change to the previous
behavior? (From the code, I think it shouldn't, but who knows.)
Quoting Malte in issue873:
"There are some small things that should eventually be
addressed, like constructors that should be explicit and exception classes that
should behave more like normal exceptions [...]"