Fix select with block doesn't return newly built records in has_many association

The `select` in `QueryMethods` is also an enumerable method.
Enumerable methods with block should delegate to `records` on
`CollectionProxy`, not `scope`.

Fixes #28348.

3 files changed, 14 insertions, 2 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index e00a62b8cd..9d20e59745 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Fix select with block doesn't return newly built records in has_many association.
+
+    Fixes #28348.
+
+    *Ryuta Kamizono*
+
 *   Check whether `Rails.application` defined before calling it
 
     In #27674 we changed the migration generator to generate migrations at the
diff --git a/activerecord/lib/active_record/associations/collection_proxy.rb b/activerecord/lib/active_record/associations/collection_proxy.rb
index 55bf2e0ff0..bc2f359c65 100644
--- a/activerecord/lib/active_record/associations/collection_proxy.rb
+++ b/activerecord/lib/active_record/associations/collection_proxy.rb
@@ -78,7 +78,7 @@ module ActiveRecord
       #   #      #<Pet id: nil, name: "Choo-Choo">
       #   #    ]
       #
-      #   person.pets.select(:id, :name )
+      #   person.pets.select(:id, :name)
       #   # => [
       #   #      #<Pet id: 1, name: "Fancy-Fancy">,
       #   #      #<Pet id: 2, name: "Spook">,
@@ -1121,7 +1121,7 @@ module ActiveRecord
         SpawnMethods,
       ].flat_map { |klass|
         klass.public_instance_methods(false)
-      } - self.public_instance_methods(false) + [:scoping]
+      } - self.public_instance_methods(false) - [:select] + [:scoping]
 
       delegate(*delegate_methods, to: :scope)
 
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index ede3a44090..14f515fa1c 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -783,6 +783,12 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal [1], posts(:welcome).comments.select { |c| c.id == 1 }.map(&:id)
   end
 
+  def test_select_with_block_and_dirty_target
+    assert_equal 2, posts(:welcome).comments.select { true }.size
+    posts(:welcome).comments.build
+    assert_equal 3, posts(:welcome).comments.select { true }.size
+  end
+
   def test_select_without_foreign_key
     assert_equal companies(:first_firm).accounts.first.credit_limit, companies(:first_firm).accounts.select(:credit_limit).first.credit_limit
   end