Merge pull request #11945 from Mik-die/polymorphic-decorator

check class hierarchy with is_a? in PredicateBuilder.expand

3 files changed, 32 insertions, 1 deletions

diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md
index a485feaf47..a0680cd86f 100644
--- a/activerecord/CHANGELOG.md
+++ b/activerecord/CHANGELOG.md
@@ -1,3 +1,9 @@
+*   Fix PredicateBuilder so polymorhic association keys in `where` clause can
+    also accept not only `ActiveRecord::Base` direct descendances (decorated
+    models, for example).
+
+    *Mikhail Dieterle*
+
 *   PostgreSQL adapter recognizes negative money values formatted with
     parentheses (eg. `($1.25) # => -1.25`)).
     Fixes #11899.
diff --git a/activerecord/lib/active_record/relation/predicate_builder.rb b/activerecord/lib/active_record/relation/predicate_builder.rb
index 8948f2bba5..c60cd27a83 100644
--- a/activerecord/lib/active_record/relation/predicate_builder.rb
+++ b/activerecord/lib/active_record/relation/predicate_builder.rb
@@ -55,7 +55,7 @@ module ActiveRecord
       #
       # For polymorphic relationships, find the foreign key and type:
       # PriceEstimate.where(estimate_of: treasure)
-      if klass && value.class < Base && reflection = klass.reflect_on_association(column.to_sym)
+      if klass && value.is_a?(Base) && reflection = klass.reflect_on_association(column.to_sym)
         if reflection.polymorphic?
           queries << build(table[reflection.foreign_type], value.class.base_class)
         end
diff --git a/activerecord/test/cases/relation/where_test.rb b/activerecord/test/cases/relation/where_test.rb
index d333be3560..3e460fa3d6 100644
--- a/activerecord/test/cases/relation/where_test.rb
+++ b/activerecord/test/cases/relation/where_test.rb
@@ -81,6 +81,31 @@ module ActiveRecord
       assert_equal expected.to_sql, actual.to_sql
     end
 
+    def test_decorated_polymorphic_where
+      treasure_decorator = Struct.new(:model) do
+        def self.method_missing(method, *args, &block)
+          Treasure.send(method, *args, &block)
+        end
+
+        def is_a?(klass)
+          model.is_a?(klass)
+        end
+
+        def method_missing(method, *args, &block)
+          model.send(method, *args, &block)
+        end
+      end
+
+      treasure = Treasure.new
+      treasure.id = 1
+      decorated_treasure = treasure_decorator.new(treasure)
+
+      expected = PriceEstimate.where(estimate_of_type: 'Treasure', estimate_of_id: 1)
+      actual   = PriceEstimate.where(estimate_of: decorated_treasure)
+
+      assert_equal expected.to_sql, actual.to_sql
+    end
+
     def test_aliased_attribute
       expected = Topic.where(heading: 'The First Topic')
       actual   = Topic.where(title: 'The First Topic')