Fix when unfollow a tag, my post also disappears from the home timeli…

…ne (mastodon#27391)

app/lib/feed_manager.rb

@@ -207,6 +207,7 @@ def unmerge_tag_from_home(from_tag, into_account)
     # also tagged with another followed hashtag or from a followed user
     scope = from_tag.statuses
                     .where(id: timeline_status_ids)
+                    .where.not(account: into_account)
                     .where.not(account: into_account.following)
                     .tagged_with_none(TagFollow.where(account: into_account).pluck(:tag_id))
 

spec/lib/feed_manager_spec.rb

@@ -562,6 +562,44 @@
     end
   end
 
+  describe '#unmerge_tag_from_home' do
+    let(:receiver) { Fabricate(:account) }
+    let(:tag) { Fabricate(:tag) }
+
+    it 'leaves a tagged status' do
+      status = Fabricate(:status)
+      status.tags << tag
+      described_class.instance.push_to_home(receiver, status)
+
+      described_class.instance.unmerge_tag_from_home(tag, receiver)
+
+      expect(redis.zrange("feed:home:#{receiver.id}", 0, -1)).to_not include(status.id.to_s)
+    end
+
+    it 'remains a tagged status written by receiver\'s followee' do
+      followee = Fabricate(:account)
+      receiver.follow!(followee)
+
+      status = Fabricate(:status, account: followee)
+      status.tags << tag
+      described_class.instance.push_to_home(receiver, status)
+
+      described_class.instance.unmerge_tag_from_home(tag, receiver)
+
+      expect(redis.zrange("feed:home:#{receiver.id}", 0, -1)).to include(status.id.to_s)
+    end
+
+    it 'remains a tagged status written by receiver' do
+      status = Fabricate(:status, account: receiver)
+      status.tags << tag
+      described_class.instance.push_to_home(receiver, status)
+
+      described_class.instance.unmerge_tag_from_home(tag, receiver)
+
+      expect(redis.zrange("feed:home:#{receiver.id}", 0, -1)).to include(status.id.to_s)
+    end
+  end
+
   describe '#clear_from_home' do
     let(:account) { Fabricate(:account) }
     let(:followed_account) { Fabricate(:account) }