We have a committer who set his email address to empty for some reason, and now all our builds fail on the project. The stack trace suggests that a patch prior to line 365 of GitChangeSet might fix the problem.

 
public User findOrCreateUser(String csAuthor, String csAuthorEmail, boolean createAccountBasedOnEmail) {

User user;

if (csAuthor == null) {
return User.getUnknown();
}

if (createAccountBasedOnEmail) {
if (csAuthorEmail == null || "".equals(csAuthorEmail)) { // new code block
return User.getUnknown();
}
user = User.get(csAuthorEmail, false); // line 365