Preserve node marks when cloning a node

src/nodeevents.cpp

@@ -69,19 +69,19 @@ void NodeEvents::Emit(const detail::node& node, EventHandler& handler,
     case NodeType::Undefined:
       break;
     case NodeType::Null:
-      handler.OnNull(Mark(), anchor);
+      handler.OnNull(node.mark(), anchor);
       break;
     case NodeType::Scalar:
-      handler.OnScalar(Mark(), node.tag(), anchor, node.scalar());
+      handler.OnScalar(node.mark(), node.tag(), anchor, node.scalar());
       break;
     case NodeType::Sequence:
-      handler.OnSequenceStart(Mark(), node.tag(), anchor, node.style());
+      handler.OnSequenceStart(node.mark(), node.tag(), anchor, node.style());
       for (auto element : node)
         Emit(*element, handler, am);
       handler.OnSequenceEnd();
       break;
     case NodeType::Map:
-      handler.OnMapStart(Mark(), node.tag(), anchor, node.style());
+      handler.OnMapStart(node.mark(), node.tag(), anchor, node.style());
       for (auto element : node) {
         Emit(*element.first, handler, am);
         Emit(*element.second, handler, am);

test/integration/clone_node_test.cpp

@@ -0,0 +1,84 @@
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include <yaml-cpp/yaml.h>
+
+struct ComparableMark {
+  int pos;
+  int line, column;
+
+  ComparableMark(int pos, int line, int column)
+      : pos(pos), line(line), column(column) {}
+};
+
+bool operator==(const YAML::Mark& a, const ComparableMark& b) {
+  return a.pos == b.pos && a.line == b.line && a.column == b.column;
+}
+
+template <typename Mark>
+void PrintMark(const Mark& mark, std::ostream* os) {
+  *os << mark.line << ':' << mark.column << " (pos " << mark.pos << ')';
+}
+
+void PrintTo(const ComparableMark& mark, std::ostream* os) {
+  PrintMark(mark, os);
+}
+
+namespace YAML {
+void PrintTo(const Mark& mark, std::ostream* os) { PrintMark(mark, os); }
+}  // namespace YAML
+
+TEST(CloneNodeTest, PreserveMark) {
+  std::string yaml_str = R"(
+scalar: value
+sequence: [1, 2, 3]
+"null": null
+[1, 2, 3]: value  # check non-scalar keys
+)";
+
+  auto checkMarks = [](const YAML::Node& root_node) {
+    EXPECT_EQ(root_node.Mark(), ComparableMark(1, 1, 0));
+
+    const YAML::Node& scalar = root_node["scalar"];
+    EXPECT_EQ(scalar.Mark(), ComparableMark(9, 1, 8));
+
+    const YAML::Node& sequence = root_node["sequence"];
+    EXPECT_EQ(sequence.Mark(), ComparableMark(25, 2, 10));
+    EXPECT_EQ(sequence[0].Mark(), ComparableMark(26, 2, 11));
+    EXPECT_EQ(sequence[1].Mark(), ComparableMark(29, 2, 14));
+    EXPECT_EQ(sequence[2].Mark(), ComparableMark(32, 2, 17));
+
+    const YAML::Node& null = root_node["null"];
+    EXPECT_EQ(null.Mark(), ComparableMark(43, 3, 8));
+
+    YAML::Node sequence_key;
+    std::vector<YAML::Mark> key_marks;
+    for (auto it = root_node.begin(); it != root_node.end(); ++it) {
+      // Not assuming any key order
+      key_marks.emplace_back(it->first.Mark());
+      if (it->first.IsSequence()) {
+        sequence_key.reset(it->first);
+      }
+    }
+
+    EXPECT_THAT(key_marks,
+                testing::UnorderedElementsAre(
+                    ComparableMark(1, 1, 0), ComparableMark(15, 2, 0),
+                    ComparableMark(35, 3, 0), ComparableMark(48, 4, 0)));
+
+    ASSERT_TRUE(sequence_key);
+    EXPECT_EQ(sequence_key[0].Mark(), ComparableMark(49, 4, 1));
+    EXPECT_EQ(sequence_key[1].Mark(), ComparableMark(52, 4, 4));
+    EXPECT_EQ(sequence_key[2].Mark(), ComparableMark(55, 4, 7));
+  };
+
+  YAML::Node root_node = YAML::Load(yaml_str);
+  {
+    SCOPED_TRACE("original node");
+    checkMarks(root_node);
+  }
+  YAML::Node cloned_node = YAML::Clone(root_node);
+  {
+    SCOPED_TRACE("cloned node");
+    checkMarks(cloned_node);
+  }
+}