+sub git_get_ref ($) {
+ my ($refname) = @_;
+ my $got = cmdoutput_errok @git, qw(show-ref --), $refname;
+ if (!defined $got) {
+ $?==256 or fail "git show-ref failed (status $?)";
+ printdebug "ref $refname= [show-ref exited 1]\n";
+ return '';
+ }
+ if ($got =~ m/^(\w+) \Q$refname\E$/m) {
+ printdebug "ref $refname=$1\n";
+ return $1;
+ } else {
+ printdebug "ref $refname= [no match]\n";
+ return '';
+ }
+}
+