3 files changed, 49 insertions, 0 deletions
diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 0f544d1b5d..7db99d4aeb 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,21 @@
+*   Reset the collection association when calling `reset` on it.
+
+    Before:
+
+        post.comments.loaded? # => true
+        post.comments.reset
+        post.comments.loaded? # => true
+
+    After:
+
+        post.comments.loaded? # => true
+        post.comments.reset
+        post.comments.loaded? # => false
+
+    Fixes #13777.
+
+    *Kelsey Schlarman*
+
 *   Make enum fields work as expected with the `ActiveModel::Dirty` API.
 
     Before this change, using the dirty API would have surprising results:
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index a67b834a80..eba688866c 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -1004,6 +1004,28 @@ module ActiveRecord
         proxy_association.reload
         self
       end
+
+      # Unloads the association. Returns +self+.
+      #
+      #   class Person < ActiveRecord::Base
+      #     has_many :pets
+      #   end
+      #
+      #   person.pets # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets # uses the pets cache
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      #
+      #   person.pets.reset # clears the pets cache
+      #
+      #   person.pets  # fetches pets from the database
+      #   # => [#<Pet id: 1, name: "Snoop", group: "dogs", person_id: 1>]
+      def reset
+        proxy_association.reset
+        proxy_association.reset_scope
+        self
+      end
     end
   end
 end
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index 48e6fc5cd4..f663b5490c 100644
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -255,6 +255,15 @@ class AssociationProxyTest < ActiveRecord::TestCase
       assert_equal man, man.interests.where("1=1").first.man
     end
   end
+
+  def test_reset_unloads_target
+    david = authors(:david)
+    david.posts.reload
+
+    assert david.posts.loaded?
+    david.posts.reset
+    assert !david.posts.loaded?
+  end
 end
 
 class OverridingAssociationsTest < ActiveRecord::TestCase