Ensure AR #second, #third, etc. finders work through associations

This commit fixes two regressions introduced in cafe31a078 where
newly created finder methods #second, #third, #forth, and #fifth
caused a NoMethodError error on reload associations and where we
were pulling the wrong element out of cached associations.

Examples:

  some_book.authors.reload.second

  # Before
  # => NoMethodError: undefined method 'first' for nil:NilClass

  # After
  # => #<Author id: 2, name: "Sally Second", ...>

  some_book.first.authors.first
  some_book.first.authors.second

  # Before
  # => #<Author id: 1, name: "Freddy First", ...>
  # => #<Author id: 1, name: "Freddy First", ...>

  # After
  # => #<Author id: 1, name: "Freddy First", ...>
  # => #<Author id: 2, name: "Sally Second", ...>

Fixes #13783.

1 files changed, 5 insertions, 5 deletions

diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index fe5de44409..703f805188 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -401,7 +401,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
     assert_equal new_client, companies(:first_firm).clients_of_firm.last
     assert !companies(:first_firm).save
     assert !new_client.persisted?
-    assert_equal 1, companies(:first_firm).clients_of_firm(true).size
+    assert_equal 2, companies(:first_firm).clients_of_firm(true).size
   end
 
   def test_adding_before_save
@@ -455,7 +455,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
     company.name += '-changed'
     assert_queries(2) { assert company.save }
     assert new_client.persisted?
-    assert_equal 2, company.clients_of_firm(true).size
+    assert_equal 3, company.clients_of_firm(true).size
   end
 
   def test_build_many_before_save
@@ -464,7 +464,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
 
     company.name += '-changed'
     assert_queries(3) { assert company.save }
-    assert_equal 3, company.clients_of_firm(true).size
+    assert_equal 4, company.clients_of_firm(true).size
   end
 
   def test_build_via_block_before_save
@@ -475,7 +475,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
     company.name += '-changed'
     assert_queries(2) { assert company.save }
     assert new_client.persisted?
-    assert_equal 2, company.clients_of_firm(true).size
+    assert_equal 3, company.clients_of_firm(true).size
   end
 
   def test_build_many_via_block_before_save
@@ -488,7 +488,7 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
 
     company.name += '-changed'
     assert_queries(3) { assert company.save }
-    assert_equal 3, company.clients_of_firm(true).size
+    assert_equal 4, company.clients_of_firm(true).size
   end
 
   def test_replace_on_new_object