failing unittest: multiple assignment to Node variable with references in document

include/yaml-cpp/node/impl.h

@@ -239,11 +239,12 @@ inline void Node::Assign(char* rhs) {
 }
 
 inline Node& Node::operator=(const Node& rhs) {
-  if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
-  if (is(rhs))
-    return *this;
-  AssignNode(rhs);
+  AssignData(rhs);
+  return *this;
+}
+
+inline Node& Node::operator=(const NodeAlias& rhs) {
+  AssignNode(rhs.m_node);
   return *this;
 }
 

include/yaml-cpp/node/node.h

@@ -26,6 +26,7 @@ struct iterator_value;
 }  // namespace YAML
 
 namespace YAML {
+class YAML_CPP_API NodeAlias;
 class YAML_CPP_API Node {
  public:
   friend class NodeBuilder;
@@ -81,6 +82,7 @@ class YAML_CPP_API Node {
   template <typename T>
   Node& operator=(const T& rhs);
   Node& operator=(const Node& rhs);
+  Node& operator=(const NodeAlias& rhs);
   void reset(const Node& rhs = Node());
 
   // size/iterator
@@ -134,6 +136,14 @@ class YAML_CPP_API Node {
   mutable detail::node* m_pNode;
 };
 
+class NodeAlias {
+  friend class Node;
+public:
+  NodeAlias(const Node& node) : m_node(node) {}
+private:
+  const Node& m_node;
+};
+
 YAML_CPP_API bool operator==(const Node& lhs, const Node& rhs);
 
 YAML_CPP_API Node Clone(const Node& node);

test/integration/handler_test.cpp

@@ -1,5 +1,4 @@
 #include "handler_test.h"
-#include "specexamples.h"   // IWYU pragma: keep
 #include "yaml-cpp/yaml.h"  // IWYU pragma: keep
 
 #include "gmock/gmock.h"

test/integration/load_node_test.cpp

@@ -78,6 +78,22 @@ TEST(LoadNodeTest, IterateMap) {
   EXPECT_EQ(3, i);
 }
 
+TEST(LoadNodeTest, AliasMultipleAssign) {
+  Node doc = Load("{A: &DEFAULT {str: string, int: 42, float: 3.1415}, B: *DEFAULT}");
+
+  for (YAML::const_iterator it = doc.begin(); it != doc.end(); ++it) {
+    SCOPED_TRACE("group " + it->first.as<std::string>());
+    Node value;
+
+    value = it->second["str"];
+    EXPECT_STREQ(value.as<std::string>().c_str(), "string");
+    value = it->second["float"];
+    EXPECT_EQ(value.as<float>(), 3.1415f);
+    value = it->second["int"];
+    EXPECT_EQ(value.as<int>(), 42);
+  }
+}
+
 #ifdef BOOST_FOREACH
 TEST(LoadNodeTest, ForEach) {
   Node node = Load("[1, 3, 5, 7]");

test/node/node_test.cpp

@@ -254,7 +254,7 @@ TEST(NodeTest, StdPair) {
 TEST(NodeTest, SimpleAlias) {
   Node node;
   node["foo"] = "value";
-  node["bar"] = node["foo"];
+  node["bar"] = NodeAlias(node["foo"]);
   EXPECT_EQ("value", node["foo"].as<std::string>());
   EXPECT_EQ("value", node["bar"].as<std::string>());
   EXPECT_EQ(node["bar"], node["foo"]);
@@ -274,7 +274,7 @@ TEST(NodeTest, AliasAsKey) {
 
 TEST(NodeTest, SelfReferenceSequence) {
   Node node;
-  node[0] = node;
+  node[0] = NodeAlias(node);
   EXPECT_TRUE(node.IsSequence());
   EXPECT_EQ(1, node.size());
   EXPECT_EQ(node, node[0]);
@@ -284,7 +284,7 @@ TEST(NodeTest, SelfReferenceSequence) {
 
 TEST(NodeTest, ValueSelfReferenceMap) {
   Node node;
-  node["key"] = node;
+  node["key"] = NodeAlias(node);
   EXPECT_TRUE(node.IsMap());
   EXPECT_EQ(1, node.size());
   EXPECT_EQ(node, node["key"]);
@@ -302,7 +302,7 @@ TEST(NodeTest, KeySelfReferenceMap) {
 
 TEST(NodeTest, SelfReferenceMap) {
   Node node;
-  node[node] = node;
+  node[node] = NodeAlias(node);
   EXPECT_TRUE(node.IsMap());
   EXPECT_EQ(1, node.size());
   EXPECT_EQ(node, node[node]);
@@ -322,7 +322,7 @@ TEST(NodeTest, TempMapVariable) {
 TEST(NodeTest, TempMapVariableAlias) {
   Node node;
   Node tmp = node["key"];
-  tmp = node["other"];
+  tmp = NodeAlias(node["other"]);
   node["other"] = "value";
   EXPECT_TRUE(node.IsMap());
   EXPECT_EQ(2, node.size());