sub begin_convert_from () {
my $head = get_head();
+ my ($ffqs, $ffqm, $symref, $ffq_prev, $gdrlast) = ffq_prev_branchinfo();
+
+ fail "ffq-prev exists, this is already managed by git-debrebase!"
+ if $ffq_prev && git_get_ref $ffq_prev;
return ($head, undef);
}