+sub git_check_unmodified () {
+ foreach my $cached (qw(0 1)) {
+ my @cmd = qw(git diff --quiet);
+ push @cmd, qw(--cached) if $cached;
+ push @cmd, qw(HEAD);
+ debugcmd "+",@cmd;
+ $!=0; $?=-1; system @cmd;
+ return if !$?;
+ if ($?==256) {
+ fail
+ $cached
+ ? "git index contains changes (does not match HEAD)"
+ : "working tree is dirty (does not match HEAD)";
+ } else {
+ failedcmd @cmd;
+ }
+ }
+}
+