Update Users::Sidebar not to cache AR object (#8394)

app/services/suggester/users/sidebar.rb

@@ -4,33 +4,39 @@ module Suggester
       def initialize(user, given_tag)
         @user = user
         @given_tag = given_tag
+        @minimum_reaction_count = Rails.env.production? ? 25 : 0
       end
 
       def suggest
-        Rails.cache.fetch(generate_cache_name, expires_in: 120.hours) do
-          reaction_count = Rails.env.production? ? 25 : 0
-          user_ids = Article.published.tagged_with([given_tag], any: true).
-            where("public_reactions_count > ?", reaction_count).
-            where("published_at > ?", 4.months.ago).
-            where("user_id != ?", user.id).
-            where.not(user_id: user.following_by_type("User")).
-            pluck(:user_id)
-          group_one = User.select(:id, :name, :username, :profile_image, :summary).
-            where(id: user_ids).
-            order("reputation_modifier DESC").limit(20).to_a
-          group_two = User.select(:id, :name, :username, :profile_image, :summary).
-            where(id: user_ids).
-            order(Arel.sql("RANDOM()")).limit(20).to_a
-          (group_one + group_two).uniq
+        suggested_user_ids = Rails.cache.fetch(generate_cache_name, expires_in: 120.hours) do
+          (reputable_user_ids + random_user_ids).uniq
         end
+        User.select(:id, :name, :username, :profile_image, :summary).where(id: suggested_user_ids)
       end
 
       private
 
-      attr_reader :user, :given_tag
+      attr_reader :user, :given_tag, :minimum_reaction_count
 
       def generate_cache_name
-        "tag-#{given_tag}_user-#{user.id}-#{user.last_followed_at}/tag-follow-sugggestions"
+        "tag-#{given_tag}-user-#{user.id}-#{user.last_followed_at}/tag-follow-suggestions"
+      end
+
+      def active_authors_for_given_tags
+        @active_authors_for_given_tags ||= Article.published.tagged_with([given_tag], any: true).
+          where("public_reactions_count >= ?", minimum_reaction_count).
+          where("published_at > ?", 4.months.ago).
+          where("user_id != ?", user.id).
+          where.not(user_id: user.following_by_type("User")).
+          pluck(:user_id)
+      end
+
+      def reputable_user_ids
+        User.where(id: active_authors_for_given_tags).order("reputation_modifier DESC").limit(20).pluck(:id)
+      end
+
+      def random_user_ids
+        User.where(id: active_authors_for_given_tags).order(Arel.sql("RANDOM()")).limit(20).pluck(:id)
       end
     end
   end

spec/services/suggester/users/sidebar_spec.rb

@@ -3,17 +3,16 @@ require "rails_helper"
 RSpec.describe Suggester::Users::Sidebar, type: :service do
   let(:user) { create(:user) }
 
-  it "does not include calling user" do
-    create_list(:user, 3)
-    tags = []
-    3.times { tags << create(:tag) }
-    expect(described_class.new(user, tags).suggest).not_to include(user)
+  it "returns user suggestions" do
+    tags = "html"
+    article1 = create(:article, tags: tags)
+    article2 = create(:article, tags: tags)
+    expect(described_class.new(user, tags).suggest.to_a).to eq([article1.user, article2.user])
   end
 
-  it "returns the same number created" do
+  it "returns no user if there's not enough sample" do
     create_list(:user, 3)
-    tags = []
-    3.times { tags << create(:tag) }
-    expect(described_class.new(user, tags).suggest.size).to eq(0)
+    tags = create_list(:tag, 3)
+    expect(described_class.new(user, tags).suggest).to be_empty
   end
 end