From 4bb39ac3c37fc5319898300c1067bb47443d6041 Mon Sep 17 00:00:00 2001
From: Matt Jankowski <matt@jankowski.online>
Date: Mon, 27 Feb 2023 03:31:15 -0500
Subject: [PATCH] Fix single-record invalid condition on PollVote (#23810)

---
 app/models/poll_vote.rb          |  1 +
 app/validators/vote_validator.rb | 26 +++++++++++++++--
 spec/models/poll_vote_spec.rb    | 49 ++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/app/models/poll_vote.rb b/app/models/poll_vote.rb
index 00eaedd1298..92d74a6dbc7 100644
--- a/app/models/poll_vote.rb
+++ b/app/models/poll_vote.rb
@@ -23,6 +23,7 @@ class PollVote < ApplicationRecord
   after_create_commit :increment_counter_cache
 
   delegate :local?, to: :account
+  delegate :multiple?, :expired?, to: :poll, prefix: true
 
   def object_type
     :vote
diff --git a/app/validators/vote_validator.rb b/app/validators/vote_validator.rb
index b1692562d41..9c55f9ab6da 100644
--- a/app/validators/vote_validator.rb
+++ b/app/validators/vote_validator.rb
@@ -2,13 +2,13 @@
 
 class VoteValidator < ActiveModel::Validator
   def validate(vote)
-    vote.errors.add(:base, I18n.t('polls.errors.expired')) if vote.poll.expired?
+    vote.errors.add(:base, I18n.t('polls.errors.expired')) if vote.poll_expired?
 
     vote.errors.add(:base, I18n.t('polls.errors.invalid_choice')) if invalid_choice?(vote)
 
-    if vote.poll.multiple? && vote.poll.votes.where(account: vote.account, choice: vote.choice).exists?
+    if vote.poll_multiple? && already_voted_for_same_choice_on_multiple_poll?(vote)
       vote.errors.add(:base, I18n.t('polls.errors.already_voted'))
-    elsif !vote.poll.multiple? && vote.poll.votes.where(account: vote.account).exists?
+    elsif !vote.poll_multiple? && already_voted_on_non_multiple_poll?(vote)
       vote.errors.add(:base, I18n.t('polls.errors.already_voted'))
     end
   end
@@ -18,4 +18,24 @@ class VoteValidator < ActiveModel::Validator
   def invalid_choice?(vote)
     vote.choice.negative? || vote.choice >= vote.poll.options.size
   end
+
+  def already_voted_for_same_choice_on_multiple_poll?(vote)
+    if vote.persisted?
+      account_votes_on_same_poll(vote).where(choice: vote.choice).where.not(poll_votes: { id: vote }).exists?
+    else
+      account_votes_on_same_poll(vote).where(choice: vote.choice).exists?
+    end
+  end
+
+  def already_voted_on_non_multiple_poll?(vote)
+    if vote.persisted?
+      account_votes_on_same_poll(vote).where.not(poll_votes: { id: vote }).exists?
+    else
+      account_votes_on_same_poll(vote).exists?
+    end
+  end
+
+  def account_votes_on_same_poll(vote)
+    vote.poll.votes.where(account: vote.account)
+  end
 end
diff --git a/spec/models/poll_vote_spec.rb b/spec/models/poll_vote_spec.rb
index 563f346993a..6886a82aa82 100644
--- a/spec/models/poll_vote_spec.rb
+++ b/spec/models/poll_vote_spec.rb
@@ -10,4 +10,53 @@ RSpec.describe PollVote, type: :model do
       expect(poll_vote.object_type).to eq :vote
     end
   end
+
+  describe 'validations' do
+    context 'with a vote on an expired poll' do
+      it 'marks the vote invalid' do
+        poll = Fabricate.build(:poll, expires_at: 30.days.ago)
+
+        vote = Fabricate.build(:poll_vote, poll: poll)
+        expect(vote).to_not be_valid
+      end
+    end
+
+    context 'with invalid choices' do
+      it 'marks vote invalid with negative choice' do
+        poll = Fabricate.build(:poll)
+
+        vote = Fabricate.build(:poll_vote, poll: poll, choice: -100)
+        expect(vote).to_not be_valid
+      end
+
+      it 'marks vote invalid with choice in excess of options' do
+        poll = Fabricate.build(:poll, options: %w(a b c))
+
+        vote = Fabricate.build(:poll_vote, poll: poll, choice: 10)
+        expect(vote).to_not be_valid
+      end
+    end
+
+    context 'with a poll where multiple is true' do
+      it 'does not allow a second vote on same choice from same account' do
+        poll = Fabricate(:poll, multiple: true, options: %w(a b c))
+        first_vote = Fabricate(:poll_vote, poll: poll, choice: 1)
+        expect(first_vote).to be_valid
+
+        second_vote = Fabricate.build(:poll_vote, account: first_vote.account, poll: poll, choice: 1)
+        expect(second_vote).to_not be_valid
+      end
+    end
+
+    context 'with a poll where multiple is false' do
+      it 'does not allow a second vote from same account' do
+        poll = Fabricate(:poll, multiple: false, options: %w(a b c))
+        first_vote = Fabricate(:poll_vote, poll: poll)
+        expect(first_vote).to be_valid
+
+        second_vote = Fabricate.build(:poll_vote, account: first_vote.account, poll: poll)
+        expect(second_vote).to_not be_valid
+      end
+    end
+  end
 end