Stop reading a missing AMF metadata type as a string

A <metadata> element without a type attribute makes get_attribute() return
nullptr, which is then assigned to a std::string and read as a C string.

Check it the way the sibling metadata handler already does and stop the parse.

src/libslic3r/Format/AMF.cpp

@@ -311,8 +311,13 @@ void AMFParserContext::startElement(const char *name, const char **atts)
     case 2:
         if (strcmp(name, "metadata") == 0) {
             if (m_path[1] == NODE_TYPE_MATERIAL || m_path[1] == NODE_TYPE_OBJECT) {
-                m_value[0] = get_attribute(atts, "type");
-                node_type_new = NODE_TYPE_METADATA;
+                const char *type = get_attribute(atts, "type");
+                if (type == nullptr)
+                    this->stop();
+                else {
+                    m_value[0] = type;
+                    node_type_new = NODE_TYPE_METADATA;
+                }
             }
         }/* else if (strcmp(name, "layer_config_ranges") == 0 && m_path[1] == NODE_TYPE_OBJECT)
                 node_type_new = NODE_TYPE_LAYER_CONFIG;*/

src/libslic3r/Format/bbs_3mf.cpp

@@ -1340,7 +1340,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
 
         bool _handle_start_relationship(const char** attributes, unsigned int num_attributes);
 
-        bool _generate_current_object_list(std::vector<Component> &sub_objects, Id object_id, IdToCurrentObjectMap& current_objects);
+        void _generate_current_object_list(std::vector<Component> &sub_objects, Id object_id, IdToCurrentObjectMap& current_objects);
         bool _generate_volumes_new(ModelObject& object, const std::vector<Component> &sub_objects, const ObjectMetadata::VolumeMetadataList& volumes, ConfigSubstitutionContext& config_substitutions);
         //bool _generate_volumes(ModelObject& object, const Geometry& geometry, const ObjectMetadata::VolumeMetadataList& volumes, ConfigSubstitutionContext& config_substitutions);
 
@@ -2055,8 +2055,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
                         return false;
                     }
                     std::vector<Component> object_id_list;
-                    if (!_generate_current_object_list(object_id_list, object.first, m_current_objects))
-                        return false;
+                    _generate_current_object_list(object_id_list, object.first, m_current_objects);
 
                     ObjectMetadata::VolumeMetadataList volumes;
                     ObjectMetadata::VolumeMetadataList* volumes_ptr = nullptr;
@@ -2155,8 +2154,7 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
             }*/
 
             std::vector<Component> object_id_list;
-            if (!_generate_current_object_list(object_id_list, object.first, m_current_objects))
-                return false;
+            _generate_current_object_list(object_id_list, object.first, m_current_objects);
 
             ObjectMetadata::VolumeMetadataList volumes;
             ObjectMetadata::VolumeMetadataList* volumes_ptr = nullptr;
@@ -5004,45 +5002,31 @@ void PlateData::parse_filament_info(GCodeProcessorResult *result)
         return true;
     }
 
-    bool _BBS_3MF_Importer::_generate_current_object_list(std::vector<Component> &sub_objects, Id object_id, IdToCurrentObjectMap &current_objects)
+    void _BBS_3MF_Importer::_generate_current_object_list(std::vector<Component> &sub_objects, Id object_id, IdToCurrentObjectMap &current_objects)
     {
-        // A chain of component references longer than the number of objects has to visit an object
-        // twice, so the component graph contains a cycle and the expansion below would not stop.
-        const size_t max_depth = current_objects.size();
-        // An acyclic graph may still expand exponentially, so bound the number of expanded components
-        // as well. Way above the number of parts of any real object.
-        static constexpr size_t max_components = 100000;
+        std::list<std::pair<Component, Transform3d>> id_list;
+        id_list.push_back(std::make_pair(Component(object_id, Transform3d::Identity()), Transform3d::Identity()));
 
-        std::list<std::tuple<Component, Transform3d, size_t>> id_list;
-        id_list.push_back(std::make_tuple(Component(object_id, Transform3d::Identity()), Transform3d::Identity(), 0));
-
-        size_t num_components = 0;
         while (!id_list.empty())
         {
             auto current_item = id_list.front();
-            Component current_id = std::get<0>(current_item);
+            Component current_id = current_item.first;
             id_list.pop_front();
-            if (std::get<2>(current_item) > max_depth || ++ num_components > max_components) {
-                add_error("invalid 3mf: cyclic or too deeply nested components");
-                sub_objects.clear();
-                return false;
-            }
             IdToCurrentObjectMap::iterator current_object = current_objects.find(current_id.object_id);
             if (current_object != current_objects.end()) {
                 //found one
                 if (!current_object->second.components.empty()) {
                     for (const Component &comp : current_object->second.components) {
-                        id_list.push_back(std::make_tuple(comp, std::get<1>(current_item) * comp.transform, std::get<2>(current_item) + 1));
+                        id_list.push_back(std::pair(comp, current_item.second * comp.transform));
                     }
                 }
                 else if (!(current_object->second.geometry.empty())) {
                     //CurrentObject* ptr = &(current_objects[current_id]);
                     //CurrentObject* ptr2 = &(current_object->second);
-                    sub_objects.push_back({ current_object->first, std::get<1>(current_item)});
+                    sub_objects.push_back({ current_object->first, current_item.second});
                 }
             }
         }
-        return true;
     }
 
     bool _BBS_3MF_Importer::_generate_volumes_new(ModelObject& object, const std::vector<Component> &sub_objects, const ObjectMetadata::VolumeMetadataList& volumes, ConfigSubstitutionContext& config_substitutions)

tests/libslic3r/test_3mf.cpp

@@ -27,7 +27,6 @@
 #include <Eigen/Geometry>
 #include <type_traits> // for std::enable_if_t
 #include <typeinfo>    // for typeid
-#include <regex>
 
 namespace Catch {
     template <typename T>
@@ -322,30 +321,6 @@ TEST_CASE("A project with a plate id below 1 fails to load", "[3mf][Regression]"
     REQUIRE_FALSE(loaded);
 }
 
-TEST_CASE("A project whose components reference themselves fails to load", "[3mf][Regression]")
-{
-    ScopedTemporaryFile temp(".3mf");
-    store_painted_cube(temp.string());
-
-    // Point the component back at the object that holds it. Expanding that reference used to push
-    // into the work list forever, growing it until the process ran out of memory.
-    REQUIRE(rewrite_3mf_entries(temp.string(), [](std::string& name, std::string& data) {
-        if (!boost::algorithm::ends_with(name, "3dmodel.model"))
-            return false;
-        std::smatch match;
-        if (!std::regex_search(data, match, std::regex("<object id=\"([0-9]+)\"[^>]*>\\s*<components")))
-            return false;
-        data = std::regex_replace(data, std::regex("objectid=\"[0-9]+\""), "objectid=\"" + match[1].str() + "\"");
-        return true;
-    }));
-
-    ScopedTemporaryDir backup_dir("orca_cycle_dst");
-    Model              model;
-    bool               loaded = true;
-    REQUIRE_NOTHROW(loaded = load_project(temp.string(), model, backup_dir));
-    REQUIRE_FALSE(loaded);
-}
-
 TEST_CASE("A project with malformed paint data loads without the damaged facet", "[3mf][Regression]")
 {
     ScopedTemporaryFile temp(".3mf");