Background

The LibGit2SharpException class has a constructor overload that takes two parameters and attempts to call String.Format to convert the values into a single string.

Unfortunately if the provided message contains text between curly braces then the string.format throws an exception.

Related PR OctopusDeploy#10

Result

Since this message could have any value, it seems risky to assume that the provided string will have a {0} that will accept the GitErrorCategory as a replacement value. In fact it seems rather unlikely that this would typically apply at all. As a result this handler would ignore the error category in the best case, or throw an exception in the worst case.

Alternative

I'd also be happy to ignore the category entirely since its likely that it is of type GitErrorCategory.Unknown anyway

Alternative snippet

exceptionBuilder = (m, c) => new LibGit2SharpException(m);