Mongoize is not called on update_all, when $set operator is used

lib/mongoid/extensions/hash.rb

@@ -49,7 +49,7 @@ def __consolidate__(klass)
             consolidated[key].update(value)
           else
             consolidated["$set"] ||= {}
-            consolidated["$set"].update(key => mongoize_for(key, klass, key, value))
+            consolidated["$set"].update(key => mongoize_for("$set", klass, key, value))
           end
         end
         consolidated
@@ -199,7 +199,7 @@ def value_for(operator, klass, key, value)
         case operator
         when "$rename" then value.to_s
         when "$addToSet", "$push" then value.mongoize
-        else mongoize_for(operator, klass, operator, value)
+        else mongoize_for(operator, klass, key, value)
         end
       end
 

spec/mongoid/contextual/mongo_spec.rb

@@ -3765,15 +3765,15 @@
         context "when the attributes must be mongoized" do
 
           before do
-            context.update_all("$set" => { member_count: "1" })
+            context.update_all("$set" => { location: LatLng.new(52.30, 13.25) })
           end
 
           it "updates the first matching document" do
-            expect(depeche_mode.reload.member_count).to eq(1)
+            expect(depeche_mode.reload.location).to eq(LatLng.new(52.30, 13.25))
           end
 
           it "updates the last matching document" do
-            expect(new_order.reload.member_count).to eq(1)
+            expect(new_order.reload.location).to eq(LatLng.new(52.30, 13.25))
           end
         end
       end

spec/support/models/band.rb

@@ -23,6 +23,7 @@ class Band
   field :mojo, type: Object
   field :tags, type: Hash
   field :fans
+  field :location, type: LatLng
 
   embeds_many :records, cascade_callbacks: true
   embeds_many :notes, as: :noteable, cascade_callbacks: true, validate: false

spec/support/models/lat_lng.rb

@@ -4,6 +4,8 @@ class LatLng
   attr_accessor :lat, :lng
 
   def self.demongoize(object)
+    return if object.nil?
+
     LatLng.new(object[1], object[0])
   end
 
@@ -14,4 +16,8 @@ def initialize(lat, lng)
   def mongoize
     [ lng, lat ]
   end
+
+  def ==(other)
+    lat == other.lat && lng == other.lng
+  end
 end