Cloning values fetched from variables in order to set their paths and line-numbers to the point of reference. (Using the original values would result in paths and line-numbers being reported as the point of assignment, which is not helpful for debugging.)

Author: Aaron Leung

eval_apply.cpp

@@ -286,7 +286,7 @@ namespace Sass {
 
       case Node::variable: {
         if (!env.query(expr.token())) throw_eval_error("reference to unbound variable " + expr.token().to_string(), expr.path(), expr.line());
-        return env[expr.token()];
+        return new_Node(expr.path(), expr.line(), env[expr.token()]);
       } break;
 
       case Node::image_url: {

node_factory.cpp

@@ -27,13 +27,37 @@ namespace Sass {
     return ip_cpy;
   }
 
+  // returns a deep-copy of its argument, but uses the path and line that are passed in
+  Node_Impl* Node_Factory::alloc_Node_Impl(string& path, size_t line, Node_Impl* ip)
+  {
+    Node_Impl* ip_cpy = new Node_Impl(*ip);
+    pool_.push_back(ip_cpy);
+    if (ip_cpy->has_children) {
+      for (size_t i = 0, S = ip_cpy->size(); i < S; ++i) {
+        Node n(ip_cpy->at(i));
+        ip_cpy->at(i) = (*this)(path, line, n);
+      }
+    }
+    return ip_cpy;
+  }
+
+
   // for cloning nodes
   Node Node_Factory::operator()(const Node& n1)
   {
     Node_Impl* ip_cpy = alloc_Node_Impl(n1.ip_); // deep-copy the implementation object
     return Node(ip_cpy);
   }
 
+  // for cloning nodes and resetting their path and line-number fields
+  Node Node_Factory::operator()(string& path, size_t line, const Node& n1)
+  {
+    Node_Impl* ip_cpy = alloc_Node_Impl(path, line, n1.ip_); // deep-copy the implementation object
+    ip_cpy->path = path;
+    ip_cpy->line = line;
+    return Node(ip_cpy);
+  }
+
   // for making leaf nodes out of terminals/tokens
   Node Node_Factory::operator()(Node::Type type, string path, size_t line, Token t)
   {

node_factory.hpp

@@ -17,9 +17,11 @@ namespace Sass {
     Node_Impl* alloc_Node_Impl(Node::Type type, string file, size_t line);
     // returns a deep-copy of its argument
     Node_Impl* alloc_Node_Impl(Node_Impl* ip);
+    Node_Impl* alloc_Node_Impl(string& path, size_t line, Node_Impl* ip);
   public:
     // for cloning nodes
     Node operator()(const Node& n1);
+    Node operator()(string& path, size_t line, const Node& n1);
     // for making leaf nodes out of terminals/tokens
     Node operator()(Node::Type type, string file, size_t line, Token t);
     // for making boolean values or interior nodes that have children