Merge pull request #14124 from arthurnn/fix_14116

Fix collection proxy exists? regression

2 files changed, 8 insertions, 5 deletions

diff --git a/activerecord/lib/active_record/associations/collection_association.rb b/activerecord/lib/active_record/associations/collection_association.rb
index 03ca00fa70..89b7945c78 100644
--- a/activerecord/lib/active_record/associations/collection_association.rb
+++ b/activerecord/lib/active_record/associations/collection_association.rb
@@ -24,10 +24,6 @@ module ActiveRecord
     # If you need to work on all current children, new and existing records,
     # +load_target+ and the +loaded+ flag are your friends.
     class CollectionAssociation < Association #:nodoc:
-      def initialize(owner, reflection)
-        super
-        @proxy = CollectionProxy.create(klass, self)
-      end
 
       # Implements the reader method, e.g. foo.items for Foo.has_many :items
       def reader(force_reload = false)
@@ -37,7 +33,7 @@ module ActiveRecord
           reload
         end
 
-        @proxy
+        @proxy ||= CollectionProxy.create(klass, self)
       end
 
       # Implements the writer method, e.g. foo.items= for Foo.has_many :items
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index 47592f312e..026a7fe635 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -817,6 +817,13 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert author.named_categories(true).include?(category)
   end
 
+  def test_collection_exists
+    author   = authors(:mary)
+    category = Category.create!(author_ids: [author.id], name: "Primary")
+    assert category.authors.exists?(id: author.id)
+    assert category.reload.authors.exists?(id: author.id)
+  end
+
   def test_collection_delete_with_nonstandard_primary_key_on_belongs_to
     author   = authors(:mary)
     category = author.named_categories.create(:name => "Primary")