MONGOID-5624 Fix alias issue when store_as is different case (#5675)

* trying a fix for aliased field names

* add a test case for bug

* remove to_s

* Remove _ids aliases

* Revert "Remove _ids aliases"

This reverts commit 24b9e67.

* Add stored_as_associations

* Cleanup

* Fix code review remarks

---------

Co-authored-by: Dmitry Rybakov <dmitry.rybakov@mongodb.com>

lib/mongoid/association/macros.rb

@@ -35,10 +35,15 @@ module Macros
         # @api private
         class_attribute :aliased_associations
 
+        # @return [ Set<String> ] The set of associations that are configured 
+        #   with :store_as parameter.
+        class_attribute :stored_as_associations
+
         self.embedded = false
         self.embedded_relations = BSON::Document.new
         self.relations = BSON::Document.new
         self.aliased_associations = {}
+        self.stored_as_associations = Set.new
       end
 
       # This is convenience for libraries still on the old API.
@@ -219,6 +224,7 @@ def define_association!(macro_name, name, options = {}, &block)
             self.relations = self.relations.merge(name => assoc)
             if assoc.embedded? && assoc.respond_to?(:store_as) && assoc.store_as != name
               self.aliased_associations[assoc.store_as] = name
+              self.stored_as_associations << assoc.store_as
             end
           end
         end

lib/mongoid/attributes/processing.rb

@@ -43,22 +43,46 @@ def process_attributes(attrs = nil)
       # @return [ true | false ] True if pending, false if not.
       def pending_attribute?(key, value)
         name = key.to_s
-
         aliased = if aliased_associations.key?(name)
           aliased_associations[name]
         else
           name
         end
-
         if relations.has_key?(aliased)
-          pending_relations[name] = value
+          set_pending_relation(name, aliased, value)
           return true
         end
         if nested_attributes.has_key?(aliased)
-          pending_nested[name] = value
+          set_pending_nested(name, aliased, value)
           return true
         end
-        return false
+        false
+      end
+
+      # Set value of the pending relation.
+      #
+      # @param [ Symbol ] name The name of the relation.
+      # @param [ Symbol ] aliased The aliased name of the relation.
+      # @param [ Object ] value The value of the relation.
+      def set_pending_relation(name, aliased, value)
+        if stored_as_associations.include?(name)
+          pending_relations[aliased] = value
+        else
+          pending_relations[name] = value
+        end
+      end
+
+      # Set value of the pending nested attribute.
+      #
+      # @param [ Symbol ] name The name of the nested attribute.
+      # @param [ Symbol ] aliased The aliased name of the nested attribute.
+      # @param [ Object ] value The value of the nested attribute.
+      def set_pending_nested(name, aliased, value)
+        if stored_as_associations.include?(name)
+          pending_nested[aliased] = value
+        else
+          pending_nested[name] = value
+        end
       end
 
       # Get all the pending associations that need to be set.

spec/mongoid/attributes_spec.rb

@@ -2711,4 +2711,31 @@
       catalog.set_field.should == Set.new([ 1, 2 ])
     end
   end
+
+  context 'when an embedded field has a capitalized store_as name' do
+    let(:person) { Person.new(Purse: { brand: 'Gucci' }) }
+
+    it 'sets the value' do
+      expect(person.purse.brand).to eq('Gucci')
+    end
+
+    it 'saves successfully' do
+      expect(person.save!).to eq(true)
+    end
+
+    context 'when persisted' do
+      before do
+        person.save!
+        person.reload
+      end
+
+      it 'persists the value' do
+        expect(person.reload.purse.brand).to eq('Gucci')
+      end
+
+      it 'uses the correct key in the database' do
+        expect(person.collection.find(_id: person.id).first['Purse']['_id']).to eq(person.purse.id)
+      end
+    end
+  end
 end

spec/support/models/person.rb

@@ -70,6 +70,7 @@ def find_by_street(street)
   embeds_many :messages, validate: false
 
   embeds_one :passport, autobuild: true, store_as: :pass, validate: false
+  embeds_one :purse, store_as: "Purse"
   embeds_one :pet, class_name: "Animal", validate: false
   embeds_one :name, as: :namable, validate: false do
     def extension

spec/support/models/purse.rb

@@ -0,0 +1,9 @@
+# frozen_string_literal: true
+
+class Purse
+  include Mongoid::Document
+
+  field :brand, type: String
+
+  embedded_in :person
+end