Revert DM support in HomeFeed#from_database

Fixes #1746

Queries could get prohibitively expensive.

app/models/home_feed.rb

@@ -44,10 +44,8 @@ class HomeFeed < Feed
   protected
 
   def from_database(limit, max_id, since_id, min_id)
-    scope = Status.where(account: @account.following)
+    scope = Status.where(account: @account).or(Status.where(account: @account.following))
-    scope = scope.left_outer_joins(:mentions)
+    scope = scope.where(visibility: %i(public unlisted private))
-    scope = scope.where(visibility: %i(public unlisted private)).or(scope.where(mentions: { account_id: @account.id })).group(Status.arel_table[:id])
-    scope = scope.or(Status.where(account: @account))
     scope
       .to_a_paginated_by_id(limit, min_id: min_id, max_id: max_id, since_id: since_id)
       .reject { |status| FeedManager.instance.filter?(:home, status, @account) }

spec/models/home_feed_spec.rb

@@ -19,32 +19,23 @@ RSpec.describe HomeFeed, type: :model do
       Fabricate(:status, account: other,    id: 11)
       Fabricate(:status, account: followed, id: 12, visibility: :private)
       Fabricate(:status, account: followed, id: 13, visibility: :direct)
-      Fabricate(:status, account: account,  id: 14, visibility: :direct)
-      dm = Fabricate(:status, account: followed, id: 15, visibility: :direct)
-      Fabricate(:mention, account: account, status: dm)
     end
 
     context 'when feed is generated' do
       before do
         FeedManager.instance.populate_home(account)
-
-        # Add direct messages because populate_home does not do that
-        Redis.current.zadd(
-          FeedManager.instance.key(:home, account.id),
-          [[14, 14], [15, 15]]
-        )
       end
 
       it 'gets statuses with ids in the range from redis with database' do
-        results = subject.get(5)
+        results = subject.get(3)
 
-        expect(results.map(&:id)).to eq [15, 14, 12, 10, 3]
+        expect(results.map(&:id)).to eq [12, 10, 3]
         expect(results.first.attributes.keys).to eq %w(id updated_at)
       end
 
       it 'with since_id present' do
-        results = subject.get(5, nil, 3, nil)
+        results = subject.get(3, nil, 3, nil)
-        expect(results.map(&:id)).to eq [15, 14, 12, 10]
+        expect(results.map(&:id)).to eq [12, 10]
       end
 
       it 'with min_id present' do
@@ -57,25 +48,19 @@ RSpec.describe HomeFeed, type: :model do
       before do
         FeedManager.instance.populate_home(account)
 
-        # Add direct messages because populate_home does not do that
-        Redis.current.zadd(
-          FeedManager.instance.key(:home, account.id),
-          [[14, 14], [15, 15]]
-        )
-
         Redis.current.zremrangebyrank(FeedManager.instance.key(:home, account.id), 0, -2)
       end
 
       it 'gets statuses with ids in the range from redis with database' do
-        results = subject.get(5)
+        results = subject.get(3)
 
-        expect(results.map(&:id)).to eq [15, 14, 12, 10, 3]
+        expect(results.map(&:id)).to eq [12, 10, 3]
         expect(results.first.attributes.keys).to eq %w(id updated_at)
       end
 
       it 'with since_id present' do
-        results = subject.get(5, nil, 3, nil)
+        results = subject.get(3, nil, 3, nil)
-        expect(results.map(&:id)).to eq [15, 14, 12, 10]
+        expect(results.map(&:id)).to eq [12, 10]
       end
 
       it 'with min_id present' do
@@ -90,14 +75,14 @@ RSpec.describe HomeFeed, type: :model do
       end
 
       it 'returns from database' do
-        results = subject.get(5)
+        results = subject.get(3)
 
-        expect(results.map(&:id)).to eq [15, 14, 12, 10, 3]
+        expect(results.map(&:id)).to eq [12, 10, 3]
       end
 
       it 'with since_id present' do
-        results = subject.get(5, nil, 3, nil)
+        results = subject.get(3, nil, 3, nil)
-        expect(results.map(&:id)).to eq [15, 14, 12, 10]
+        expect(results.map(&:id)).to eq [12, 10]
       end
 
       it 'with min_id present' do