FIX: anonymous user filtering bug in PostView (#7089)

* FIX: anonymous user filtering bug in PostView

lib/topic_view.rb

@@ -603,9 +603,12 @@ class TopicView
     @filtered_posts = unfiltered_posts
 
     if SiteSetting.ignore_user_enabled
-      @filtered_posts = @filtered_posts.where.not("user_id IN (?) AND id <> ?",
-                                                  IgnoredUser.where(user_id: @user.id).select(:ignored_user_id),
-                                                  first_post_id)
+      ignored_user_ids = IgnoredUser.where(user_id: @user&.id).pluck(:ignored_user_id)
+
+      if ignored_user_ids.present?
+        @filtered_posts = @filtered_posts.where.not("user_id IN (?) AND id <> ?", ignored_user_ids, first_post_id)
+        @contains_gaps = true
+      end
     end
 
     # Filters

spec/components/topic_view_spec.rb

@@ -31,6 +31,71 @@ describe TopicView do
     expect { TopicView.new(topic.id, admin) }.not_to raise_error
   end
 
+  context "setup_filtered_posts" do
+    describe "filters posts with ignored users" do
+      let!(:user) { Fabricate(:user) }
+      let!(:ignored_user) { Fabricate(:ignored_user, user: evil_trout, ignored_user: user) }
+      let!(:post) { Fabricate(:post, topic: topic, user: first_poster) }
+      let!(:post2) { Fabricate(:post, topic: topic, user: evil_trout) }
+      let!(:post3) { Fabricate(:post, topic: topic, user: user) }
+
+      describe "when SiteSetting.ignore_user_enabled is false" do
+        it "does not filter out ignored user posts" do
+          SiteSetting.ignore_user_enabled = false
+
+          tv = TopicView.new(topic.id, evil_trout)
+          expect(tv.filtered_post_ids.size).to eq(3)
+          expect(tv.filtered_post_ids).to match_array([post.id, post2.id, post3.id])
+        end
+      end
+
+      describe "when SiteSetting.ignore_user_enabled is true" do
+
+        before do
+          SiteSetting.ignore_user_enabled = true
+        end
+
+        it "filters out ignored user posts" do
+          tv = TopicView.new(topic.id, evil_trout)
+          expect(tv.filtered_post_ids.size).to eq(2)
+          expect(tv.filtered_post_ids).to match_array([post.id, post2.id])
+        end
+
+        describe "when an ignored user made the original post" do
+          let!(:post) { Fabricate(:post, topic: topic, user: user) }
+
+          it "filters out ignored user posts only" do
+            tv = TopicView.new(topic.id, evil_trout)
+            expect(tv.filtered_post_ids.size).to eq(2)
+            expect(tv.filtered_post_ids).to match_array([post.id, post2.id])
+          end
+        end
+
+        describe "when an anonymous user made a post" do
+          let(:anonymous) { Fabricate(:anonymous) }
+          let!(:post4) { Fabricate(:post, topic: topic, user: anonymous) }
+
+          it "filters out ignored user posts only" do
+            tv = TopicView.new(topic.id, evil_trout)
+            expect(tv.filtered_post_ids.size).to eq(3)
+            expect(tv.filtered_post_ids).to match_array([post.id, post2.id, post4.id])
+          end
+        end
+
+        describe "when an anonymous (non signed-in) user is viewing a Topic" do
+          let(:anonymous) { Fabricate(:anonymous) }
+          let!(:post4) { Fabricate(:post, topic: topic, user: anonymous) }
+
+          it "filters out ignored user posts only" do
+            tv = TopicView.new(topic.id, nil)
+            expect(tv.filtered_post_ids.size).to eq(4)
+            expect(tv.filtered_post_ids).to match_array([post.id, post2.id, post3.id, post4.id])
+          end
+        end
+      end
+    end
+  end
+
   context "chunk_size" do
     it "returns `chunk_size` by default" do
       expect(TopicView.new(topic.id, evil_trout).chunk_size).to eq(TopicView.chunk_size)