Re msg125818, I agree that the mixed EOLs is also a potential problem, though the proposed solution behaves better than the status quo, where the EOLs get converted without warning.

It would be desirable for the patch to be more robust in that situation (providing a useful error message about why it fails). What might even be better is to retain newlines even if they're mixed. I'll explore a cross-platform technique to consistently retain newlines as encountered.