Dissallow people from changing their votes in the Vote ApprovalAction

application/models/rows/ApprovalActionQueue.php

@@ -110,7 +110,7 @@ class ApprovalActionQueue extends ApprovalAction
      */
     public function userMadeDecision(Request $request, User $user, $decision)
     {
-        $vote = ApproverVotes::getInstance()->fetchByRequestUserAndAction($request, $user, $this);
+        $vote = $this->getUserDecision($request, $user);
         if ($vote) {
             $vote->vote = $decision;
         } else {

application/models/rows/ApprovalActionVote.php

@@ -69,6 +69,12 @@ class ApprovalActionVote extends ApprovalActionQueue
      */
     public function userMadeDecision(Request $request, User $user, $decision)
     {
+        $vote = $this->getUserDecision($request, $user);
+        if ($vote) {
+            // TODO: don't fail silently when someone tries to vote again.
+            return;
+        }
+
         parent::userMadeDecision($request, $user, $decision);
     }