printdebug " checking history vsn=$vsn tagref=$tagref\n";
$?=0; my $r = system qw(git show-ref --verify --quiet), $tagref;
return 1 if !$r;
printdebug " checking history vsn=$vsn tagref=$tagref\n";
$?=0; my $r = system qw(git show-ref --verify --quiet), $tagref;
return 1 if !$r;