Using subselect for `delete_all` with `limit` or `offset`

Arel doesn't support subselect generation for DELETE unlike UPDATE yet,
but we already have that generation in connection adapters. We can
simply use the subselect generated by that one.

2 files changed, 20 insertions, 2 deletions

diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 3440781fee..07c4a17fb1 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -76,6 +76,26 @@ class PersistenceTest < ActiveRecord::TestCase
       assert_equal "bulk update!", posts(:thinking).body
       assert_not_equal "bulk update!", posts(:welcome).body
     end
+
+    def test_delete_all_with_order_and_limit_deletes_subset_only
+      author = authors(:david)
+      limited_posts = Post.where(author: author).order(:id).limit(1)
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.delete_all
+      assert_raise(ActiveRecord::RecordNotFound) { posts(:welcome) }
+      assert posts(:thinking)
+    end
+
+    def test_delete_all_with_order_and_limit_and_offset_deletes_subset_only
+      author = authors(:david)
+      limited_posts = Post.where(author: author).order(:id).limit(1).offset(1)
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.delete_all
+      assert_raise(ActiveRecord::RecordNotFound) { posts(:thinking) }
+      assert posts(:welcome)
+    end
   end
 
   def test_update_many
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 675aafabda..915ff03c2c 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -896,11 +896,9 @@ class RelationTest < ActiveRecord::TestCase
   end
 
   def test_delete_all_with_unpermitted_relation_raises_error
-    assert_raises(ActiveRecord::ActiveRecordError) { Author.limit(10).delete_all }
     assert_raises(ActiveRecord::ActiveRecordError) { Author.distinct.delete_all }
     assert_raises(ActiveRecord::ActiveRecordError) { Author.group(:name).delete_all }
     assert_raises(ActiveRecord::ActiveRecordError) { Author.having("SUM(id) < 3").delete_all }
-    assert_raises(ActiveRecord::ActiveRecordError) { Author.offset(10).delete_all }
   end
 
   def test_select_with_aggregates