Generate subquery for Relation passed as array condition for where

Instead of executing 2 queries for fetching records filtered by array condition with Relation,
added generation of subquery to current query.

This behaviour will be consistent when passes Relation as hash condition to where

Closes: #12415

2 files changed, 11 insertions, 0 deletions

diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index f814947ab2..0cd8595ba6 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -626,6 +626,11 @@ class RelationTest < ActiveRecord::TestCase
       relation = Author.where(:id => Author.where(:id => david.id))
       assert_equal [david], relation.to_a
     }
+
+    assert_queries(1) {
+      relation = Author.where('id in (?)', Author.where(id: david).select(:id))
+      assert_equal [david], relation.to_a
+    }
   end
 
   def test_find_all_using_where_with_relation_and_alternate_primary_key
diff --git a/activerecord/test/cases/sanitize_test.rb b/activerecord/test/cases/sanitize_test.rb
index 082570c55b..4c0762deca 100644
--- a/activerecord/test/cases/sanitize_test.rb
+++ b/activerecord/test/cases/sanitize_test.rb
@@ -31,4 +31,10 @@ class SanitizeTest < ActiveRecord::TestCase
     assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper"])
     assert_equal "name=#{quoted_bambi_and_thumper}", Binary.send(:sanitize_sql_array, ["name=?", "Bambi\nand\nThumper".mb_chars])
   end
+
+  def test_sanitize_sql_array_handles_relations
+    assert_match(/\(\bselect\b.*?\bwhere\b.*?\)/i,
+      Binary.send(:sanitize_sql_array, ["id in (?)", Binary.where(id: 1)]),
+      "should sanitize `Relation` as subquery")
+  end
 end