switch aptitude to apt-get, since aptitude will sometimes automatically do things that are unrelated to the task at hand, such as deinstalling automatically installed packages, which can be undesirable behavior

manifests/upgrade_package.pp

@@ -22,7 +22,7 @@ define apt::upgrade_package ($version = "") {
     }
   }
 
-  exec { "aptitude -y install ${name}${version_suffix}":
+  exec { "apt-get --force-yes -o DPkg::Options::=--force-confold install ${name}${version_suffix}":
     onlyif => [ "grep-status -F Status installed -a -P $name -q", "apt-show-versions -u $name | grep -q upgradeable" ],
     require => [
       Exec['apt_updated'],