Better error messages

include/yaml-cpp/exceptions.h

@@ -114,6 +114,35 @@ inline const std::string KEY_NOT_FOUND_WITH_KEY(
   stream << KEY_NOT_FOUND << ": " << key;
   return stream.str();
 }
+
+template <typename T>
+inline const std::string BAD_SUBSCRIPT_WITH_KEY(
+    const T&, typename disable_if<is_numeric<T>>::type* = 0) {
+  return BAD_SUBSCRIPT;
+}
+
+inline const std::string BAD_SUBSCRIPT_WITH_KEY(const std::string& key) {
+  std::stringstream stream;
+  stream << BAD_SUBSCRIPT << " (key: '" << key << "')";
+  return stream.str();
+}
+
+template <typename T>
+inline const std::string BAD_SUBSCRIPT_WITH_KEY(
+    const T& key, typename enable_if<is_numeric<T>>::type* = 0) {
+  std::stringstream stream;
+  stream << BAD_SUBSCRIPT << " (key: '" << key << "')";
+  return stream.str();
+}
+
+inline const std::string INVALID_NODE_WITH_KEY(const std::string& key) {
+  std::stringstream stream;
+  if (key.empty()) {
+    return INVALID_NODE;
+  }
+  stream << "invalid node - first invalid key: '" << key << "'";
+  return stream.str();
+}
 }
 
 class YAML_CPP_API Exception : public std::runtime_error {
@@ -194,8 +223,9 @@ inline TypedKeyNotFound<T> MakeTypedKeyNotFound(const Mark& mark,
 
 class YAML_CPP_API InvalidNode : public RepresentationException {
  public:
-  InvalidNode()
+  InvalidNode(std::string key)
-      : RepresentationException(Mark::null_mark(), ErrorMsg::INVALID_NODE) {}
+      : RepresentationException(Mark::null_mark(),
+                                ErrorMsg::INVALID_NODE_WITH_KEY(key)) {}
   InvalidNode(const InvalidNode&) = default;
   virtual ~InvalidNode() YAML_CPP_NOEXCEPT;
 };
@@ -224,8 +254,10 @@ class YAML_CPP_API BadDereference : public RepresentationException {
 
 class YAML_CPP_API BadSubscript : public RepresentationException {
  public:
-  BadSubscript()
+  template <typename Key>
-      : RepresentationException(Mark::null_mark(), ErrorMsg::BAD_SUBSCRIPT) {}
+  BadSubscript(const Key& key)
+      : RepresentationException(Mark::null_mark(),
+                                ErrorMsg::BAD_SUBSCRIPT_WITH_KEY(key)) {}
   BadSubscript(const BadSubscript&) = default;
   virtual ~BadSubscript() YAML_CPP_NOEXCEPT;
 };

include/yaml-cpp/node/detail/impl.h

@@ -115,7 +115,7 @@ inline node* node_data::get(const Key& key,
         return pNode;
       return NULL;
     case NodeType::Scalar:
-      throw BadSubscript();
+      throw BadSubscript(key);
   }
 
   for (node_map::const_iterator it = m_map.begin(); it != m_map.end(); ++it) {
@@ -143,7 +143,7 @@ inline node& node_data::get(const Key& key, shared_memory_holder pMemory) {
       convert_to_map(pMemory);
       break;
     case NodeType::Scalar:
-      throw BadSubscript();
+      throw BadSubscript(key);
   }
 
   for (node_map::const_iterator it = m_map.begin(); it != m_map.end(); ++it) {

include/yaml-cpp/node/impl.h

@@ -12,6 +12,7 @@
 #include "yaml-cpp/node/detail/memory.h"
 #include "yaml-cpp/node/detail/node.h"
 #include "yaml-cpp/exceptions.h"
+#include <sstream>
 #include <string>
 
 namespace YAML {
@@ -34,16 +35,21 @@ inline Node::Node(const T& rhs)
 
 inline Node::Node(const detail::iterator_value& rhs)
     : m_isValid(rhs.m_isValid),
+      m_invalidKey(rhs.m_invalidKey),
       m_pMemory(rhs.m_pMemory),
       m_pNode(rhs.m_pNode) {}
 
 inline Node::Node(const Node& rhs)
     : m_isValid(rhs.m_isValid),
+      m_invalidKey(rhs.m_invalidKey),
       m_pMemory(rhs.m_pMemory),
       m_pNode(rhs.m_pNode) {}
 
 inline Node::Node(Zombie) : m_isValid(false), m_pNode(NULL) {}
 
+inline Node::Node(Zombie, std::string key)
+    : m_isValid(false), m_invalidKey(key), m_pNode(NULL) {}
+
 inline Node::Node(detail::node& node, detail::shared_memory_holder pMemory)
     : m_isValid(true), m_pMemory(pMemory), m_pNode(&node) {}
 
@@ -51,7 +57,7 @@ inline Node::~Node() {}
 
 inline void Node::EnsureNodeExists() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   if (!m_pNode) {
     m_pMemory.reset(new detail::memory_holder);
     m_pNode = &m_pMemory->create_node();
@@ -68,14 +74,14 @@ inline bool Node::IsDefined() const {
 
 inline Mark Node::Mark() const {
   if (!m_isValid) {
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   }
   return m_pNode ? m_pNode->mark() : Mark::null_mark();
 }
 
 inline NodeType::value Node::Type() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return m_pNode ? m_pNode->type() : NodeType::Null;
 }
 
@@ -142,7 +148,7 @@ struct as_if<std::string, void> {
 template <typename T>
 inline T Node::as() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return as_if<T, void>(*this)();
 }
 
@@ -155,32 +161,32 @@ inline T Node::as(const S& fallback) const {
 
 inline const std::string& Node::Scalar() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return m_pNode ? m_pNode->scalar() : detail::node_data::empty_scalar();
 }
 
 inline const std::string& Node::Tag() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return m_pNode ? m_pNode->tag() : detail::node_data::empty_scalar();
 }
 
 inline void Node::SetTag(const std::string& tag) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->set_tag(tag);
 }
 
 inline EmitterStyle::value Node::Style() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return m_pNode ? m_pNode->style() : EmitterStyle::Default;
 }
 
 inline void Node::SetStyle(EmitterStyle::value style) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->set_style(style);
 }
@@ -188,7 +194,7 @@ inline void Node::SetStyle(EmitterStyle::value style) {
 // assignment
 inline bool Node::is(const Node& rhs) const {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   if (!m_pNode || !rhs.m_pNode)
     return false;
   return m_pNode->is(*rhs.m_pNode);
@@ -197,14 +203,14 @@ inline bool Node::is(const Node& rhs) const {
 template <typename T>
 inline Node& Node::operator=(const T& rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   Assign(rhs);
   return *this;
 }
 
 inline void Node::reset(const YAML::Node& rhs) {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   m_pMemory = rhs.m_pMemory;
   m_pNode = rhs.m_pNode;
 }
@@ -212,35 +218,35 @@ inline void Node::reset(const YAML::Node& rhs) {
 template <typename T>
 inline void Node::Assign(const T& rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   AssignData(convert<T>::encode(rhs));
 }
 
 template <>
 inline void Node::Assign(const std::string& rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->set_scalar(rhs);
 }
 
 inline void Node::Assign(const char* rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->set_scalar(rhs);
 }
 
 inline void Node::Assign(char* rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->set_scalar(rhs);
 }
 
 inline Node& Node::operator=(const Node& rhs) {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   if (is(rhs))
     return *this;
   AssignNode(rhs);
@@ -249,7 +255,7 @@ inline Node& Node::operator=(const Node& rhs) {
 
 inline void Node::AssignData(const Node& rhs) {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   rhs.EnsureNodeExists();
 
@@ -259,7 +265,7 @@ inline void Node::AssignData(const Node& rhs) {
 
 inline void Node::AssignNode(const Node& rhs) {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   rhs.EnsureNodeExists();
 
   if (!m_pNode) {
@@ -276,7 +282,7 @@ inline void Node::AssignNode(const Node& rhs) {
 // size/iterator
 inline std::size_t Node::size() const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   return m_pNode ? m_pNode->size() : 0;
 }
 
@@ -309,13 +315,13 @@ inline iterator Node::end() {
 template <typename T>
 inline void Node::push_back(const T& rhs) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   push_back(Node(rhs));
 }
 
 inline void Node::push_back(const Node& rhs) {
   if (!m_isValid || !rhs.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   rhs.EnsureNodeExists();
 
@@ -368,16 +374,27 @@ inline typename to_value_t<T>::return_type to_value(const T& t) {
 }
 }
 
+template<typename Key>
+std::string key_to_string(const Key& key) {
+  std::stringstream ss;
+  if (is_streamable<std::stringstream, Key>::value) {
+    ss << key;
+    return ss.str();
+  } else {
+    return std::string();
+  }
+}
+
 // indexing
 template <typename Key>
 inline const Node Node::operator[](const Key& key) const {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   detail::node* value = static_cast<const detail::node&>(*m_pNode)
                             .get(detail::to_value(key), m_pMemory);
   if (!value) {
-    return Node(ZombieNode);
+    return Node(ZombieNode, key_to_string(key));
   }
   return Node(*value, m_pMemory);
 }
@@ -385,7 +402,7 @@ inline const Node Node::operator[](const Key& key) const {
 template <typename Key>
 inline Node Node::operator[](const Key& key) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   detail::node& value = m_pNode->get(detail::to_value(key), m_pMemory);
   return Node(value, m_pMemory);
@@ -394,28 +411,28 @@ inline Node Node::operator[](const Key& key) {
 template <typename Key>
 inline bool Node::remove(const Key& key) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   return m_pNode->remove(detail::to_value(key), m_pMemory);
 }
 
 inline const Node Node::operator[](const Node& key) const {
   if (!m_isValid || !key.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   key.EnsureNodeExists();
   m_pMemory->merge(*key.m_pMemory);
   detail::node* value =
       static_cast<const detail::node&>(*m_pNode).get(*key.m_pNode, m_pMemory);
   if (!value) {
-    return Node(ZombieNode);
+    return Node(ZombieNode, key_to_string(key));
   }
   return Node(*value, m_pMemory);
 }
 
 inline Node Node::operator[](const Node& key) {
   if (!m_isValid || !key.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   key.EnsureNodeExists();
   m_pMemory->merge(*key.m_pMemory);
@@ -425,7 +442,7 @@ inline Node Node::operator[](const Node& key) {
 
 inline bool Node::remove(const Node& key) {
   if (!m_isValid || !key.m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   key.EnsureNodeExists();
   return m_pNode->remove(*key.m_pNode, m_pMemory);
@@ -435,7 +452,7 @@ inline bool Node::remove(const Node& key) {
 template <typename Key, typename Value>
 inline void Node::force_insert(const Key& key, const Value& value) {
   if (!m_isValid)
-    throw InvalidNode();
+    throw InvalidNode(m_invalidKey);
   EnsureNodeExists();
   m_pNode->force_insert(detail::to_value(key), detail::to_value(value),
                         m_pMemory);

include/yaml-cpp/node/node.h

@@ -116,6 +116,7 @@ class YAML_CPP_API Node {
  private:
   enum Zombie { ZombieNode };
   explicit Node(Zombie);
+  explicit Node(Zombie, std::string);
   explicit Node(detail::node& node, detail::shared_memory_holder pMemory);
 
   void EnsureNodeExists() const;
@@ -130,6 +131,7 @@ class YAML_CPP_API Node {
 
  private:
   bool m_isValid;
+  std::string m_invalidKey;
   mutable detail::shared_memory_holder m_pMemory;
   mutable detail::node* m_pNode;
 };

include/yaml-cpp/traits.h

@@ -7,6 +7,9 @@
 #pragma once
 #endif
 
+#include <type_traits>
+#include <utility>
+
 namespace YAML {
 template <typename>
 struct is_numeric {
@@ -100,4 +103,17 @@ template <class Cond, class T = void>
 struct disable_if : public disable_if_c<Cond::value, T> {};
 }
 
+template <typename S, typename T>
+class is_streamable {
+  template <typename SS, typename TT>
+  static auto test(int)
+      -> decltype(std::declval<SS&>() << std::declval<TT>(), std::true_type());
+
+  template <typename, typename>
+  static auto test(...) -> std::false_type;
+
+ public:
+  static const bool value = decltype(test<S, T>(0))::value;
+};
+
 #endif  // TRAITS_H_62B23520_7C8E_11DE_8A39_0800200C9A66

src/node_data.cpp

@@ -191,7 +191,7 @@ void node_data::insert(node& key, node& value, shared_memory_holder pMemory) {
       convert_to_map(pMemory);
       break;
     case NodeType::Scalar:
-      throw BadSubscript();
+      throw BadSubscript(key);
   }
 
   insert_map_pair(key, value);
@@ -221,7 +221,7 @@ node& node_data::get(node& key, shared_memory_holder pMemory) {
       convert_to_map(pMemory);
       break;
     case NodeType::Scalar:
-      throw BadSubscript();
+      throw BadSubscript(key);
   }
 
   for (node_map::const_iterator it = m_map.begin(); it != m_map.end(); ++it) {