Properly create through records when called with `where`

Various behaviors needed by associations (such as creating the through
record) are lost when `where` is called, since we stop having a
`CollectionProxy` and start having an `AssociationRelation` which does
not contain this behavior. I *think* we should be able to rm
`AssociationRelation`, but we have tests saying the changes required to
do that would be bad (Without saying why. Of course. >_>)

Fixes #19073.

1 files changed, 6 insertions, 0 deletions

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 6729a5a9fc..5f52c65412 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -595,6 +595,12 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
     assert posts(:thinking).reload.people(true).collect(&:first_name).include?("Jeb")
   end
 
+  def test_through_record_is_built_when_created_with_where
+    assert_difference("posts(:thinking).readers.count", 1) do
+      posts(:thinking).people.where(first_name: "Jeb").create
+    end
+  end
+
   def test_associate_with_create_and_no_options
     peeps = posts(:thinking).people.count
     posts(:thinking).people.create(:first_name => 'foo')