MONGOID-4532 Correctly determine module path for associations (#4536)

Author: saghm

lib/mongoid/association/relatable.rb

@@ -57,6 +57,10 @@ def initialize(_class, name, opts = {}, &block)
         @name = name
         @options = opts
         @extension = nil
+
+        @module_path = _class.name ? _class.name.split('::')[0..-2].join('::') : ''
+        @module_path << '::' unless @module_path.empty?
+
         create_extension!(&block)
         validate!
       end
@@ -147,7 +151,7 @@ def inverse_type; end
       #
       # @since 7.0
       def relation_class_name
-        @class_name ||= @options[:class_name] || ActiveSupport::Inflector.classify(name)
+        @class_name ||= @options[:class_name] || ActiveSupport::Inflector.classify(name_with_module)
       end
       alias :class_name :relation_class_name
 
@@ -321,6 +325,10 @@ def validate?
 
       private
 
+      def name_with_module
+        @module_path + name.to_s.capitalize
+      end
+
       # Gets the model classes with inverse associations of this model. This is used to determine
       # the classes on the other end of polymorphic relations with models.
       def inverse_association_classes

spec/mongoid/association/referenced/has_one_spec.rb

@@ -890,6 +890,33 @@ class BelongingObject; include Mongoid::Document; end
 
   describe '#relation_class_name' do
 
+    context 'when the classes are defined in a module' do
+
+      let(:define_classes) do
+        module HasOneAssociationClassName
+          class OwnedClass
+            include Mongoid::Document
+
+            belongs_to :owner_class
+          end
+
+          class OwnerClass
+            include Mongoid::Document
+
+            has_one :owned_class
+          end
+        end
+      end
+
+      it 'returns the proper namespaced class name' do
+        define_classes
+
+        expect(
+            HasOneAssociationClassName::OwnedClass.relations['owner_class'].relation_class_name
+        ).to eq('HasOneAssociationClassName::OwnerClass')
+      end
+    end
+
     context 'when the :class_name option is specified' do
 
       let(:options) do
@@ -1200,6 +1227,38 @@ class OtherBelongingObject; end
     end
   end
 
+  context 'when the classes are defined in a module' do
+
+    let(:define_classes) do
+      module HasOneAssociationModuleDefinitions
+        class OwnedClass
+          include Mongoid::Document
+
+          belongs_to :owner_class
+        end
+
+        class OwnerClass
+          include Mongoid::Document
+
+          has_one :owned_class
+        end
+      end
+    end
+
+    let(:owner) do
+      HasOneAssociationModuleDefinitions::OwnerClass.create!
+    end
+
+    let(:owned) do
+      define_classes
+      HasOneAssociationModuleDefinitions::OwnedClass.create!(owner_class: owner)
+    end
+
+    it 'successfully creates the owned document' do
+      expect { owned }.not_to raise_error
+    end
+  end
+
   describe '#nested_builder' do
 
     it 'returns an instance of Association::Nested::One' do