don't treat all associations with extensions as instance dependent.

Closes #23934.

This is a forward port of ac832a43b4d026dbad28fed196d2de69ec9928ac

Previously the scope of all associations with extensions were wrapped in
an instance dependent proc. This made it impossible to preload such
associations.

4 files changed, 33 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index 861f2c3c36..3bb4b5236e 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,11 @@
+*   Fix an issue when preloading associations with extensions.
+    Previously every association with extension methods was transformed into an
+    instance dependent scope. This is no longer the case.
+
+    Fixes #23934.
+
+    *Yves Senn*
+
 *   Deprecate `{insert|update|delete}_sql` in `DatabaseStatements`.
     Use the `{insert|update|delete}` public methods instead.
 
diff --git a/activerecord/lib/active_record/associations/builder/collection_association.rb b/activerecord/lib/active_record/associations/builder/collection_association.rb
index 56a8dc4e18..f25bd7ca9f 100644
--- a/activerecord/lib/active_record/associations/builder/collection_association.rb
+++ b/activerecord/lib/active_record/associations/builder/collection_association.rb
@@ -70,7 +70,11 @@ module ActiveRecord::Associations::Builder # :nodoc:
 
     def self.wrap_scope(scope, mod)
       if scope
-        proc { |owner| instance_exec(owner, &scope).extending(mod) }
+        if scope.arity > 0
+          proc { |owner| instance_exec(owner, &scope).extending(mod) }
+        else
+          proc { instance_exec(&scope).extending(mod) }
+        end
       else
         proc { extending(mod) }
       end
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index 3ee84fb66c..7f2a2229ee 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -1392,6 +1392,18 @@ class EagerAssociationTest < ActiveRecord::TestCase
     assert_equal('10 was not recognized for preload', exception.message)
   end
 
+  test "associations with extensions are not instance dependent" do
+    assert_nothing_raised do
+      Author.includes(:posts_with_extension).to_a
+    end
+  end
+
+  test "including associations with extensions and an instance dependent scope is not supported" do
+    e = assert_raises(ArgumentError) do
+      Author.includes(:posts_with_extension_and_instance).to_a
+    end
+    assert_match(/Preloading instance dependent scopes is not supported/, e.message)
+  end
 
   test "preloading readonly association" do
     # has-one
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index f25e31b13d..38b983eda0 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -144,6 +144,14 @@ class Author < ActiveRecord::Base
 
   has_many :posts_with_signature, ->(record) { where("posts.title LIKE ?", "%by #{record.name.downcase}%") }, class_name: "Post"
 
+  has_many :posts_with_extension, -> { order(:title) }, class_name: "Post" do
+    def extension_method; end
+  end
+
+  has_many :posts_with_extension_and_instance, ->(record) { order(:title) }, class_name: "Post" do
+    def extension_method; end
+  end
+
   attr_accessor :post_log
   after_initialize :set_post_log