Core::ResourceBase: handle polymorphic associations

releaf-core/app/lib/releaf/core/resource_base.rb

@@ -36,7 +36,11 @@ def associations_attributes
   end
 
   def association_attributes(association)
-    self.class.new(association.klass).values - [association.foreign_key]
+    self.class.new(association.klass).values - association_excluded_attributes(association)
+  end
+
+  def association_excluded_attributes(association)
+    [association.foreign_key, association.type].compact
   end
 
   def associations

releaf-core/spec/lib/releaf/core/resource_base_spec.rb

@@ -51,15 +51,26 @@
   end
 
   describe "#association_attributes" do
-    it "returns association params without `foreign_key` param" do
+    it "returns association params without association excluded attributes" do
       association = subject.resource_class.reflections[:chapters]
-      allow(association).to receive(:foreign_key).and_return("b")
       allow(described_class).to receive(:new).with(association.klass).and_call_original
       allow_any_instance_of(described_class).to receive(:values).and_return(["a", "b", "c"])
+      allow(subject).to receive(:association_excluded_attributes).and_return(["b"])
       expect(subject.association_attributes(association)).to eq(["a", "c"])
     end
   end
 
+  describe "#association_excluded_attributes" do
+    it "returns `foreign_key` and polymorphic association type key (if exists)" do
+      association = subject.resource_class.reflections[:chapters]
+      allow(association).to receive(:foreign_key).and_return("b")
+      expect(subject.association_excluded_attributes(association)).to eq(["b"])
+
+      allow(association).to receive(:type).and_return("x")
+      expect(subject.association_excluded_attributes(association)).to eq(["b", "x"])
+    end
+  end
+
   describe "#values" do
     before do
       allow(subject).to receive(:associations_attributes).and_return(["x", "y"])