From 26b7991defe1d84d10c1186a151676076946b26f Mon Sep 17 00:00:00 2001
From: Benjamin Neff <benjamin@coding4coffee.ch>
Date: Sun, 3 Jul 2016 22:52:12 +0200
Subject: [PATCH] handle empty xml-elements for nested entities

---
 lib/diaspora_federation/entity.rb           |  4 ++--
 spec/entities.rb                            |  2 +-
 spec/lib/diaspora_federation/entity_spec.rb | 16 ++++++++++++++++
 3 files changed, 19 insertions(+), 3 deletions(-)

diff --git a/lib/diaspora_federation/entity.rb b/lib/diaspora_federation/entity.rb
index 77a936a..8743c77 100644
--- a/lib/diaspora_federation/entity.rb
+++ b/lib/diaspora_federation/entity.rb
@@ -286,7 +286,7 @@ module DiasporaFederation
     # @return [Entity] parsed child entity
     private_class_method def self.parse_entity_from_node(type, root_node)
       node = root_node.xpath(type.entity_name)
-      type.from_xml(node.first) if node.any?
+      type.from_xml(node.first) if node.any? && node.first.children.any?
     end
 
     # Collect all nested children of that type and create an array in the data hash
@@ -296,7 +296,7 @@ module DiasporaFederation
     # @return [Array<Entity>] array with parsed child entities
     private_class_method def self.parse_array_from_node(type, root_node)
       node = root_node.xpath(type.entity_name)
-      node.map {|child| type.from_xml(child) } unless node.empty?
+      node.select {|child| child.children.any? }.map {|child| type.from_xml(child) } unless node.empty?
     end
 
     # Raised, if entity is not valid
diff --git a/spec/entities.rb b/spec/entities.rb
index 5d0aef0..5747df1 100644
--- a/spec/entities.rb
+++ b/spec/entities.rb
@@ -17,7 +17,7 @@ module DiasporaFederation
 
     class TestNestedEntity < DiasporaFederation::Entity
       property :asdf
-      entity :test, TestEntity
+      entity :test, TestEntity, default: nil
       entity :multi, [OtherEntity]
     end
 
diff --git a/spec/lib/diaspora_federation/entity_spec.rb b/spec/lib/diaspora_federation/entity_spec.rb
index 899f99d..99bb476 100644
--- a/spec/lib/diaspora_federation/entity_spec.rb
+++ b/spec/lib/diaspora_federation/entity_spec.rb
@@ -300,6 +300,22 @@ XML
         expect(entity.multi.first).to be_instance_of(Entities::OtherEntity)
         expect(entity.multi.first.asdf).to eq("asdf")
       end
+
+      it "handles empty xml-element for nested entities" do
+        xml = <<-XML
+<test_nested_entity>
+  <asdf>FDSA</asdf>
+  <test_entity/>
+  <other_entity/>
+</test_nested_entity>
+XML
+
+        entity = Entities::TestNestedEntity.from_xml(Nokogiri::XML::Document.parse(xml).root)
+
+        expect(entity.asdf).to eq("FDSA")
+        expect(entity.test).to be_nil
+        expect(entity.multi).to be_empty
+      end
     end
 
     context "xml_name" do