Implement import recursion check

Also adds import stack reports on errors.

src/context.cpp

@@ -27,6 +27,7 @@
 #include "listize.hpp"
 #include "extend.hpp"
 #include "remove_placeholders.hpp"
+#include "sass_functions.hpp"
 #include "functions.hpp"
 #include "backtrace.hpp"
 #include "sass2scss.h"
@@ -254,7 +255,7 @@ namespace Sass {
 
  // register include with resolved path and its content
  // memory of the resources will be freed by us on exit
- void Context::register_resource(const Include& inc, const Resource& res)
+ void Context::register_resource(const Include& inc, const Resource& res, ParserState* prstate)
  {
 
  // do not parse same resource twice
@@ -297,6 +298,24 @@ namespace Sass {
  strings.push_back(sass_strdup(inc.abs_path.c_str()));
  // create the initial parser state from resource
  ParserState pstate(strings.back(), contents, idx);
+
+ // check existing import stack for possible recursion
+ for (size_t i = 0; i < import_stack.size() - 2; ++i) {
+ auto parent = import_stack[i];
+ if (std::strcmp(parent->abs_path, import->abs_path) == 0) {
+ std::string stack("An @import loop has been found:");
+ for (size_t n = 1; n < i + 2; ++n) {
+ stack += "\n " + std::string(import_stack[n]->imp_path) +
+ " imports " + std::string(import_stack[n+1]->imp_path);
+ }
+ // implement error throw directly until we
+ // decided how to handle full stack traces
+ ParserState state = prstate ? *prstate : pstate;
+ throw Exception::InvalidSyntax(state, stack, &import_stack);
+ // error(stack, prstate ? *prstate : pstate, import_stack);
+ }
+ }
+
  // create a parser instance from the given c_str buffer
  Parser p(Parser::from_c_str(contents, *this, pstate));
  // do not yet dispose these buffers
@@ -344,7 +363,7 @@ namespace Sass {
  // the memory buffer returned must be freed by us!
  if (char* contents = read_file(resolved[0].abs_path)) {
  // register the newly resolved file resource
- register_resource(resolved[0], { contents, 0 });
+ register_resource(resolved[0], { contents, 0 }, &pstate);
  // return resolved entry
  return resolved[0];
  }
@@ -433,7 +452,7 @@ namespace Sass {
  // handle error message passed back from custom importer
  // it may (or may not) override the line and column info
  if (const char* err_message = sass_import_get_error_message(include)) {
- if (source || srcmap) register_resource({ importer, uniq_path }, { source, srcmap });
+ if (source || srcmap) register_resource({ importer, uniq_path }, { source, srcmap }, &pstate);
  if (line == std::string::npos && column == std::string::npos) error(err_message, pstate);
  else error(err_message, ParserState(ctx_path, source, Position(line, column)));
  }
@@ -447,7 +466,7 @@ namespace Sass {
  // attach information to AST node
  imp->incs().push_back(include);
  // register the resource buffers
- register_resource(include, { source, srcmap });
+ register_resource(include, { source, srcmap }, &pstate);
  }
  // only a path was retuned
  // try to load it like normal
@@ -639,6 +658,7 @@ namespace Sass {
  Expand expand(*this, &global, &backtrace);
  Cssize cssize(*this, &backtrace);
  // expand and eval the tree
+ // debug_ast(root);
  root = root->perform(&expand)->block();
  // merge and bubble certain rules
  root = root->perform(&cssize)->block();

src/context.hpp

@@ -92,7 +92,7 @@ namespace Sass {
  virtual char* render(Block* root);
  virtual char* render_srcmap();
 
- void register_resource(const Include&, const Resource&);
+ void register_resource(const Include&, const Resource&, ParserState* = 0);
  std::vector<Include> find_includes(const Importer& import);
  Include load_import(const Importer&, ParserState pstate);
 

src/error_handling.cpp

@@ -10,9 +10,10 @@ namespace Sass {
 
  namespace Exception {
 
- Base::Base(ParserState pstate, std::string msg)
+ Base::Base(ParserState pstate, std::string msg, std::vector<Sass_Import_Entry>* import_stack)
  : std::runtime_error(msg),
- msg(msg), pstate(pstate)
+ msg(msg), pstate(pstate),
+ import_stack(import_stack)
  { }
 
  const char* Base::what() const throw()
@@ -44,8 +45,8 @@ namespace Sass {
  msg += " for `" + fn + "'";
  }
 
- InvalidSyntax::InvalidSyntax(ParserState pstate, std::string msg)
- : Base(pstate, msg)
+ InvalidSyntax::InvalidSyntax(ParserState pstate, std::string msg, std::vector<Sass_Import_Entry>* import_stack)
+ : Base(pstate, msg, import_stack)
  { }
 
  }

src/error_handling.hpp

@@ -19,8 +19,9 @@ namespace Sass {
  std::string msg;
  public:
  ParserState pstate;
+ std::vector<Sass_Import_Entry>* import_stack;
  public:
- Base(ParserState pstate, std::string msg = def_msg);
+ Base(ParserState pstate, std::string msg = def_msg, std::vector<Sass_Import_Entry>* import_stack = 0);
  virtual const char* what() const throw();
  virtual ~Base() throw() {};
  };
@@ -53,7 +54,7 @@ namespace Sass {
 
  class InvalidSyntax : public Base {
  public:
- InvalidSyntax(ParserState pstate, std::string msg);
+ InvalidSyntax(ParserState pstate, std::string msg, std::vector<Sass_Import_Entry>* import_stack = 0);
  virtual ~InvalidSyntax() throw() {};
  };
 

src/sass_context.cpp

@@ -10,6 +10,7 @@
 #include "util.hpp"
 #include "context.hpp"
 #include "sass_context.hpp"
+#include "sass_functions.hpp"
 #include "ast_fwd_decl.hpp"
 #include "error_handling.hpp"
 
@@ -41,7 +42,6 @@ extern "C" {
  catch (Exception::Base& e) {
  std::stringstream msg_stream;
  std::string cwd(Sass::File::get_cwd());
- std::string rel_path(Sass::File::abs2rel(e.pstate.path, cwd, cwd));
 
  std::string msg_prefix("Error: ");
  bool got_newline = false;
@@ -60,8 +60,19 @@ extern "C" {
  ++ msg;
  }
  if (!got_newline) msg_stream << "\n";
- msg_stream << std::string(msg_prefix.size(), ' ');
- msg_stream << " on line " << e.pstate.line+1 << " of " << rel_path << "\n";
+ if (e.import_stack) {
+ for (size_t i = 1; i < e.import_stack->size() - 1; ++i) {
+ std::string path((*e.import_stack)[i]->imp_path);
+ std::string rel_path(Sass::File::abs2rel(path, cwd, cwd));
+ msg_stream << std::string(msg_prefix.size(), ' ');
+ msg_stream << (i == 1 ? " on line " : " from line ");
+ msg_stream << e.pstate.line+1 << " of " << rel_path << "\n";
+ }
+ } else {
+ std::string rel_path(Sass::File::abs2rel(e.pstate.path, cwd, cwd));
+ msg_stream << std::string(msg_prefix.size(), ' ');
+ msg_stream << " on line " << e.pstate.line+1 << " of " << rel_path << "\n";
+ }
 
  // now create the code trace (ToDo: maybe have util functions?)
  if (e.pstate.line != std::string::npos && e.pstate.column != std::string::npos) {