+sub rcs_preprevert ($) {
+ my $rev=shift;
+ my ($sha1) = $rev =~ /^($sha1_pattern)$/; # untaint
+
+ # Examine changes from root of git repo, not from any subdir,
+ # in order to see all changes.
+ my ($subdir, $rootdir) = git_find_root();
+ $git_dir=$rootdir;
+ my @commits=git_commit_info($sha1, 1);
+ $git_dir=undef;
+
+ if (! @commits) {
+ error "unknown commit"; # just in case
+ }
+
+ # git revert will fail on merge commits. Add a nice message.
+ if (exists $commits[0]->{parents} &&
+ @{$commits[0]->{parents}} > 1) {
+ error gettext("you are not allowed to revert a merge");
+ }