Remove caching in `cache_collection` (#29862)

app/controllers/concerns/cache_concern.rb

@@ -198,34 +198,19 @@ module CacheConcern
     end
   end
 
+  # TODO: Rename this method, as it does not perform any caching anymore.
   def cache_collection(raw, klass)
-    return raw unless klass.respond_to?(:with_includes)
+    return raw unless klass.respond_to?(:preload_cacheable_associations)
 
-    raw = raw.cache_ids.to_a if raw.is_a?(ActiveRecord::Relation)
-    return [] if raw.empty?
+    records = raw.to_a
 
-    cached_keys_with_value = begin
-      Rails.cache.read_multi(*raw).transform_keys(&:id).transform_values { |r| ActiveRecordCoder.load(r) }
-    rescue ActiveRecordCoder::Error
-      {} # The serialization format may have changed, let's pretend it's a cache miss.
-    end
+    klass.preload_cacheable_associations(records)
 
-    uncached_ids = raw.map(&:id) - cached_keys_with_value.keys
-
-    klass.reload_stale_associations!(cached_keys_with_value.values) if klass.respond_to?(:reload_stale_associations!)
-
-    unless uncached_ids.empty?
-      uncached = klass.where(id: uncached_ids).with_includes.index_by(&:id)
-
-      uncached.each_value do |item|
-        Rails.cache.write(item, ActiveRecordCoder.dump(item))
-      end
-    end
-
-    raw.filter_map { |item| cached_keys_with_value[item.id] || uncached[item.id] }
+    records
   end
 
+  # TODO: Rename this method, as it does not perform any caching anymore.
   def cache_collection_paginated_by_id(raw, klass, limit, options)
-    cache_collection raw.cache_ids.to_a_paginated_by_id(limit, options), klass
+    cache_collection raw.to_a_paginated_by_id(limit, options), klass
   end
 end

app/models/concerns/cacheable.rb

@@ -14,6 +14,10 @@ module Cacheable
       includes(@cache_associated)
     end
 
+    def preload_cacheable_associations(records)
+      ActiveRecord::Associations::Preloader.new(records: records, associations: @cache_associated).call
+    end
+
     def cache_ids
       select(:id, :updated_at)
     end

app/models/feed.rb

@@ -28,7 +28,7 @@ class Feed
       unhydrated = redis.zrangebyscore(key, "(#{min_id}", "(#{max_id}", limit: [0, limit], with_scores: true).map(&:first).map(&:to_i)
     end
 
-    Status.where(id: unhydrated).cache_ids
+    Status.where(id: unhydrated)
   end
 
   def key

app/models/public_feed.rb

@@ -29,7 +29,7 @@ class PublicFeed
     scope.merge!(media_only_scope) if media_only?
     scope.merge!(language_scope) if account&.chosen_languages.present?
 
-    scope.cache_ids.to_a_paginated_by_id(limit, max_id: max_id, since_id: since_id, min_id: min_id)
+    scope.to_a_paginated_by_id(limit, max_id: max_id, since_id: since_id, min_id: min_id)
   end
 
   private

app/models/status.rb

@@ -338,38 +338,6 @@ class Status < ApplicationRecord
       StatusPin.select('status_id').where(status_id: status_ids).where(account_id: account_id).each_with_object({}) { |p, h| h[p.status_id] = true }
     end
 
-    def reload_stale_associations!(cached_items)
-      account_ids = []
-
-      cached_items.each do |item|
-        account_ids << item.account_id
-        account_ids << item.reblog.account_id if item.reblog?
-      end
-
-      account_ids.uniq!
-
-      status_ids = cached_items.map { |item| item.reblog? ? item.reblog_of_id : item.id }.uniq
-
-      return if account_ids.empty?
-
-      accounts = Account.where(id: account_ids).includes(:account_stat, :user).index_by(&:id)
-
-      status_stats = StatusStat.where(status_id: status_ids).index_by(&:status_id)
-
-      cached_items.each do |item|
-        item.account = accounts[item.account_id]
-        item.reblog.account = accounts[item.reblog.account_id] if item.reblog?
-
-        if item.reblog?
-          status_stat = status_stats[item.reblog.id]
-          item.reblog.status_stat = status_stat if status_stat.present?
-        else
-          status_stat = status_stats[item.id]
-          item.status_stat = status_stat if status_stat.present?
-        end
-      end
-    end
-
     def from_text(text)
       return [] if text.blank?
 

app/models/tag_feed.rb

@@ -33,7 +33,7 @@ class TagFeed < PublicFeed
     scope.merge!(account_filters_scope) if account?
     scope.merge!(media_only_scope) if media_only?
 
-    scope.cache_ids.to_a_paginated_by_id(limit, max_id: max_id, since_id: since_id, min_id: min_id)
+    scope.to_a_paginated_by_id(limit, max_id: max_id, since_id: since_id, min_id: min_id)
   end
 
   private

spec/controllers/application_controller_spec.rb

@@ -221,39 +221,4 @@ describe ApplicationController do
 
     include_examples 'respond_with_error', 422
   end
-
-  describe 'cache_collection' do
-    subject do
-      Class.new(ApplicationController) do
-        public :cache_collection
-      end
-    end
-
-    shared_examples 'receives :with_includes' do |fabricator, klass|
-      it 'uses raw if it is not an ActiveRecord::Relation' do
-        record = Fabricate(fabricator)
-        expect(subject.new.cache_collection([record], klass)).to eq [record]
-      end
-    end
-
-    shared_examples 'cacheable' do |fabricator, klass|
-      include_examples 'receives :with_includes', fabricator, klass
-
-      it 'calls cache_ids of raw if it is an ActiveRecord::Relation' do
-        record = Fabricate(fabricator)
-        relation = klass.none
-        allow(relation).to receive(:cache_ids).and_return([record])
-        expect(subject.new.cache_collection(relation, klass)).to eq [record]
-      end
-    end
-
-    it 'returns raw unless class responds to :with_includes' do
-      raw = Object.new
-      expect(subject.new.cache_collection(raw, Object)).to eq raw
-    end
-
-    context 'with a Status' do
-      include_examples 'cacheable', :status, Status
-    end
-  end
 end

spec/models/home_feed_spec.rb

@@ -27,7 +27,6 @@ RSpec.describe HomeFeed do
         results = subject.get(3)
 
         expect(results.map(&:id)).to eq [3, 2]
-        expect(results.first.attributes.keys).to eq %w(id updated_at)
       end
     end