FIX: Don't notify or return flags on system users

app/models/post_action.rb

@@ -57,6 +57,7 @@ class PostAction < ActiveRecord::Base
                                     .joins(post: :topic)
                                     .where('posts.deleted_at' => nil)
                                     .where('topics.deleted_at' => nil)
+                                    .where('posts.user_id > 0')
                                     .count('DISTINCT posts.id')
 
     $redis.set('posts_flagged_count', posts_flagged_count)

lib/flag_query.rb

@@ -114,6 +114,7 @@ module FlagQuery
                              .joins("INNER JOIN posts ON posts.id = post_actions.post_id")
                              .joins("INNER JOIN topics ON topics.id = posts.topic_id")
                              .joins("LEFT JOIN users ON users.id = posts.user_id")
+                             .where("posts.user_id > 0")
 
     if filter == "old"
       post_actions.where("post_actions.disagreed_at IS NOT NULL OR

spec/components/flag_query_spec.rb

@@ -6,6 +6,17 @@ describe FlagQuery do
   let(:codinghorror) { Fabricate(:coding_horror) }
 
   describe "flagged_posts_report" do
+    it "does not return flags on system posts" do
+      admin = Fabricate(:admin)
+      post = create_post(user: Discourse.system_user)
+      PostAction.act(codinghorror, post, PostActionType.types[:spam])
+      posts, topics, users = FlagQuery.flagged_posts_report(admin, "")
+
+      expect(posts).to be_blank
+      expect(topics).to be_blank
+      expect(users).to be_blank
+    end
+
     it "operates correctly" do
       admin = Fabricate(:admin)
       moderator = Fabricate(:moderator)

spec/models/post_action_spec.rb

@@ -147,6 +147,12 @@ describe PostAction do
       expect(PostAction.flagged_posts_count).to eq(0)
     end
 
+    it "should ignore flags on non-human users" do
+      post = create_post(user: Discourse.system_user)
+      PostAction.act(codinghorror, post, PostActionType.types[:off_topic])
+      expect(PostAction.flagged_posts_count).to eq(0)
+    end
+
     it "should ignore validated flags" do
       post = create_post