FEATURE: rake task for merging users

plugins/poll/lib/votes_updater.rb

@@ -0,0 +1,59 @@
+module DiscoursePoll
+  class VotesUpdater
+    def self.merge_users!(source_user, target_user)
+      post_ids = PostCustomField.where(name: DiscoursePoll::VOTES_CUSTOM_FIELD)
+        .where("value :: JSON -> ? IS NOT NULL", source_user.id.to_s)
+        .pluck(:post_id)
+
+      post_ids.each do |post_id|
+        DistributedMutex.synchronize("#{DiscoursePoll::MUTEX_PREFIX}-#{post_id}") do
+          post = Post.find_by(id: post_id)
+          update_votes(post, source_user, target_user) if post
+        end
+      end
+    end
+
+    def self.update_votes(post, source_user, target_user)
+      polls = post.custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD]
+      votes = post.custom_fields[DiscoursePoll::VOTES_CUSTOM_FIELD]
+      return if polls.nil? || votes.nil? || !votes.has_key?(source_user.id.to_s)
+
+      if votes.has_key?(target_user.id.to_s)
+        remove_votes(polls, votes, source_user)
+      else
+        replace_voter_id(polls, votes, source_user, target_user)
+      end
+
+      post.save_custom_fields(true)
+    end
+
+    def self.remove_votes(polls, votes, source_user)
+      votes.delete(source_user.id.to_s).each do |poll_name, option_ids|
+        poll = polls[poll_name]
+        next unless poll && option_ids
+
+        poll["options"].each do |option|
+          if option_ids.include?(option["id"])
+            option["votes"] -= 1
+
+            voter_ids = option["voter_ids"]
+            voter_ids.delete(source_user.id) if voter_ids
+          end
+        end
+      end
+    end
+
+    def self.replace_voter_id(polls, votes, source_user, target_user)
+      votes[target_user.id.to_s] = votes.delete(source_user.id.to_s)
+
+      polls.each_value do |poll|
+        next unless poll["public"] == "true"
+
+        poll["options"].each do |option|
+          voter_ids = option["voter_ids"]
+          voter_ids << target_user.id if voter_ids&.delete(source_user.id)
+        end
+      end
+    end
+  end
+end

plugins/poll/plugin.rb

@@ -18,10 +18,12 @@ after_initialize do
     DEFAULT_POLL_NAME ||= "poll".freeze
     POLLS_CUSTOM_FIELD ||= "polls".freeze
     VOTES_CUSTOM_FIELD ||= "polls-votes".freeze
+    MUTEX_PREFIX ||= PLUGIN_NAME
 
     autoload :PostValidator, "#{Rails.root}/plugins/poll/lib/post_validator"
     autoload :PollsValidator, "#{Rails.root}/plugins/poll/lib/polls_validator"
     autoload :PollsUpdater, "#{Rails.root}/plugins/poll/lib/polls_updater"
+    autoload :VotesUpdater, "#{Rails.root}/plugins/poll/lib/votes_updater"
 
     class Engine < ::Rails::Engine
       engine_name PLUGIN_NAME
@@ -385,6 +387,10 @@ after_initialize do
                                                                            polls: post.custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD])
   end
 
+  on(:merging_users) do |source_user, target_user|
+    DiscoursePoll::VotesUpdater.merge_users!(source_user, target_user)
+  end
+
   add_to_serializer(:post, :polls, false) do
     polls = post_custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD].dup
 

plugins/poll/spec/lib/votes_updater_spec.rb

@@ -0,0 +1,94 @@
+require 'rails_helper'
+
+describe DiscoursePoll::VotesUpdater do
+  let(:target_user) { Fabricate(:user_single_email, username: 'alice', email: 'alice@example.com') }
+  let(:source_user) { Fabricate(:user_single_email, username: 'alice1', email: 'alice@work.com') }
+  let(:walter) { Fabricate(:walter_white) }
+
+  let(:target_user_id) { target_user.id.to_s }
+  let(:source_user_id) { source_user.id.to_s }
+  let(:walter_id) { walter.id.to_s }
+
+  let(:post_with_two_polls) do
+    raw = <<~RAW
+      [poll type=multiple min=2 max=3 public=true]
+      - Option 1
+      - Option 2
+      - Option 3
+      [/poll]
+
+      [poll name=private_poll]
+      - Option 1
+      - Option 2
+      - Option 3
+      [/poll]
+    RAW
+
+    Fabricate(:post, raw: raw)
+  end
+
+  let(:option1_id) { "63eb791ab5d08fc4cc855a0703ac0dd1" }
+  let(:option2_id) { "773a193533027393806fff6edd6c04f7" }
+  let(:option3_id) { "f42f567ca3136ee1322d71d7745084c7" }
+
+  def vote(post, user, option_ids, poll_name = nil)
+    poll_name ||= DiscoursePoll::DEFAULT_POLL_NAME
+    DiscoursePoll::Poll.vote(post.id, poll_name, option_ids, user)
+  end
+
+  it "should move votes to the target_user when only the source_user voted" do
+    vote(post_with_two_polls, source_user, [option1_id, option3_id])
+    vote(post_with_two_polls, walter, [option1_id, option2_id])
+
+    DiscoursePoll::VotesUpdater.merge_users!(source_user, target_user)
+    post_with_two_polls.reload
+
+    polls = post_with_two_polls.custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD]
+    expect(polls["poll"]["options"][0]["votes"]).to eq(2)
+    expect(polls["poll"]["options"][1]["votes"]).to eq(1)
+    expect(polls["poll"]["options"][2]["votes"]).to eq(1)
+
+    expect(polls["poll"]["options"][0]["voter_ids"]).to contain_exactly(target_user.id, walter.id)
+    expect(polls["poll"]["options"][1]["voter_ids"]).to contain_exactly(walter.id)
+    expect(polls["poll"]["options"][2]["voter_ids"]).to contain_exactly(target_user.id)
+
+    votes = post_with_two_polls.custom_fields[DiscoursePoll::VOTES_CUSTOM_FIELD]
+    expect(votes.keys).to contain_exactly(target_user_id, walter_id)
+    expect(votes[target_user_id]["poll"]).to contain_exactly(option1_id, option3_id)
+    expect(votes[walter_id]["poll"]).to contain_exactly(option1_id, option2_id)
+  end
+
+  it "should delete votes of the source_user if the target_user voted" do
+    vote(post_with_two_polls, source_user, [option1_id, option3_id])
+    vote(post_with_two_polls, target_user, [option2_id, option3_id])
+    vote(post_with_two_polls, walter, [option1_id, option2_id])
+
+    DiscoursePoll::VotesUpdater.merge_users!(source_user, target_user)
+    post_with_two_polls.reload
+
+    polls = post_with_two_polls.custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD]
+    expect(polls["poll"]["options"][0]["votes"]).to eq(1)
+    expect(polls["poll"]["options"][1]["votes"]).to eq(2)
+    expect(polls["poll"]["options"][2]["votes"]).to eq(1)
+
+    expect(polls["poll"]["options"][0]["voter_ids"]).to contain_exactly(walter.id)
+    expect(polls["poll"]["options"][1]["voter_ids"]).to contain_exactly(target_user.id, walter.id)
+    expect(polls["poll"]["options"][2]["voter_ids"]).to contain_exactly(target_user.id)
+
+    votes = post_with_two_polls.custom_fields[DiscoursePoll::VOTES_CUSTOM_FIELD]
+    expect(votes.keys).to contain_exactly(target_user_id, walter_id)
+    expect(votes[target_user_id]["poll"]).to contain_exactly(option2_id, option3_id)
+    expect(votes[walter_id]["poll"]).to contain_exactly(option1_id, option2_id)
+  end
+
+  it "does not add voter_ids unless the poll is public" do
+    vote(post_with_two_polls, source_user, [option1_id, option3_id], "private_poll")
+    vote(post_with_two_polls, walter, [option1_id, option2_id], "private_poll")
+
+    DiscoursePoll::VotesUpdater.merge_users!(source_user, target_user)
+    post_with_two_polls.reload
+
+    polls = post_with_two_polls.custom_fields[DiscoursePoll::POLLS_CUSTOM_FIELD]
+    polls["private_poll"]["options"].each { |o| expect(o).to_not have_key("voter_ids") }
+  end
+end