#!/usr/bin/env perl

use strict;
use warnings;

my $log_cmd = "git log -z --pretty=format:'%H\n%b'";

local $/ = "\0";

open(my $log_fh, '-|', $log_cmd) or die "Can't start git log: $!";

while (<$log_fh>) {
  chomp;
  my ($hash, $body) = split(/\n/, $_, 2);
  print($hash, "\n") if ($body =~ /\A\s*(?:[^:\n]+: +[^\n]+\n?)*\s*\Z/);
}