git-cvsimport: $cvs->file() fails silently

We have seen a few instances of files extracted from a remote CVS repo by $cvs->file() being empty, and still git-cvsimport did not die or complain. If I rewind the affected head and re-run git-cvsimport, the file is imported correctly, which makes me suspect that the server went away or there was some other networking glitch, and that the file() and _file() methods didn't handle it gracefully.

I've been through the file(), _file() and _line() methods, and they seem pretty conservative -- they die or return undef in all the right places. There _must_ be one place that we're missing but I just can't see it.

Any ideas?

martin