Only preload accounts in Collections when needed (#39143)

app/models/collection.rb

@@ -64,11 +64,15 @@ class Collection < ApplicationRecord
     !local?
   end
 
-  def items_for(account = nil)
-    result = collection_items.with_accounts
-    result = account == self.account ? result.pending_or_accepted : result.accepted
-    result = result.not_blocked_by(account) unless account.nil?
-    result
+  def items_for(account = nil, include_accounts: false)
+    @items_for ||= {}
+    @items_for[account] ||= begin
+      result = collection_items
+      result = result.with_accounts if include_accounts
+      result = account == self.account ? result.pending_or_accepted : result.accepted
+      result = result.not_blocked_by(account) unless account.nil?
+      result
+    end
   end
 
   def tag_name

app/models/collection_item.rb

@@ -43,7 +43,7 @@ class CollectionItem < ApplicationRecord
 
   scope :ordered, -> { order(position: :asc) }
   scope :with_accounts, -> { includes(account: [:account_stat, :user]) }
-  scope :not_blocked_by, ->(account) { where.not(accounts: { id: account.blocking }) }
+  scope :not_blocked_by, ->(account) { joins(:account).where.not(accounts: { id: account.blocking }) }
   scope :local, -> { joins(:collection).merge(Collection.local) }
   scope :accepted_partial, ->(account) { joins(:account).merge(Account.local).accepted.where(uri: nil, account_id: account.id) }
   scope :pending_or_accepted, -> { where(state: [:pending, :accepted]) }