Fix multi-level hash update w/o nested attributes. Fixes #1936.

CHANGELOG.md

@@ -7,6 +7,10 @@ For instructions on upgrading to newer versions, visit
 
 ### Resolved Issues
 
+* \#1936 Allow setting n levels deep embedded documents atomically without
+  conflicting mods when not using nested attributes or documents themselves
+  in an update call from the parent.
+
 * \#1957/\#1954 Ensure database name is set with inheritance.
   (Hans Hasselberg)
 

lib/mongoid/atomic.rb

@@ -252,6 +252,9 @@ def delayed_atomic_pulls
     # @example Get the atomic paths.
     #   document.atomic_paths
     #
+    # @todo: Durran: Should probably raise error for embedded docs w/o
+    #   metadata.
+    #
     # @return [ Object ] The associated path.
     #
     # @since 2.1.0

lib/mongoid/relations/embedded/many.rb

@@ -307,7 +307,11 @@ def substitute(replacement)
               atomically(:$set) do
                 base.delayed_atomic_sets.clear
                 if replacement.first.is_a?(Hash)
-                  replacement = Many.builder(base, metadata, replacement).build
+                  replacement = replacement.map do |doc|
+                    attributes = { metadata: metadata, _parent: base }
+                    attributes.merge!(doc)
+                    Factory.build(klass, attributes)
+                  end
                 end
                 docs = replacement.compact
                 proxy.target = docs
@@ -319,6 +323,10 @@ def substitute(replacement)
                 end
                 if _assigning?
                   name = _unscoped.first.atomic_path
+                  base._children.each do |child|
+                    child.delayed_atomic_sets.clear
+                  end
+                  base.instance_variable_set(:@_children, nil)
                   base.delayed_atomic_sets[name] = proxy.as_document
                 end
               end

spec/functional/mongoid/relations/embedded/many_spec.rb

@@ -3025,4 +3025,53 @@
       end
     end
   end
+
+  context "when adding a document" do
+
+    let(:person) do
+      Person.new
+    end
+
+    let(:address_one) do
+      Address.new(street: "hobrecht")
+    end
+
+    let(:first_add) do
+      person.addresses.push(address_one)
+    end
+  end
+
+  context "when updating multiple levels in one update" do
+
+    let!(:person) do
+      Person.create(
+        addresses: [
+          { locations: [{ name: "home" }]}
+        ]
+      )
+    end
+
+    context "when updating with hashes" do
+
+      let(:from_db) do
+        Person.find(person.id)
+      end
+
+      before do
+        from_db.update_attributes(
+          addresses: [
+            { locations: [{ name: "work" }]}
+          ]
+        )
+      end
+
+      let(:updated) do
+        person.reload.addresses.first.locations.first
+      end
+
+      it "updates the nested document" do
+        updated.name.should eq("work")
+      end
+    end
+  end
 end