Test That Failed Vendor Loads Are Not Kept and the Library Base Is Reused

Cover the two cache paths the first test left open: a vendor tree that fails to load is retried on the next resolution instead of being served from the cache, and a type-probed filament resolved through resolve_preset_config_type reuses the OrcaFilamentLibrary base already loaded for a sibling.

src/OrcaSlicer.cpp

@@ -53,6 +53,7 @@ using namespace nlohmann;
 
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/Config.hpp"
+#include "libslic3r/FilamentMixer.hpp"
 #include "libslic3r/Preset.hpp"
 #include "libslic3r/Geometry.hpp"
 #include "libslic3r/GCode.hpp"
@@ -162,6 +163,7 @@ std::map<int, std::string> cli_errors = {
     {CLI_FILAMENT_CAN_NOT_MAP, "Some filaments cannot be mapped to correct extruders for multi-extruder Printer."},
     {CLI_ONLY_ONE_TPU_SUPPORTED, "Not support printing 2 or more TPU filaments."},
     {CLI_FILAMENTS_NOT_SUPPORTED_BY_EXTRUDER, "Some filaments cannot be printed on the extruder mapped to."},
+    {CLI_MIXED_FILAMENT_INVALID, "A mixed filament is invalid: its components are different filament types, or it has no filament of its own."},
     {CLI_SLICING_ERROR, "Failed slicing the model. Please verify the slicing of all plates on Orca Slicer before uploading."},
     {CLI_GCODE_PATH_CONFLICTS, " G-code conflicts detected after slicing. Please make sure the 3mf file can be successfully sliced in the latest Orca Slicer. If the file slices normally in Orca Slicer, try moving the wipe tower further from other models, as we use more conservative parameters for it during upload."},
     {CLI_GCODE_PATH_IN_UNPRINTABLE_AREA, "Found G-code in unprintable area of multi-extruder printers after slicing. Please make sure the 3mf file can be successfully sliced in the latest Orca Slicer."}
@@ -2008,19 +2010,21 @@ int CLI::run(int argc, char **argv)
         }
     };
 
-    auto resolve_preset = [&ensure_cli_preset_bundle](const std::string &file, DynamicPrintConfig &config,
+    // One resolver for the whole run, so presets from the same vendor tree share its load.
+    std::unique_ptr<PresetBundle> system_preset_resolver;
+    auto resolve_preset = [&ensure_cli_preset_bundle, &system_preset_resolver](const std::string &file, DynamicPrintConfig &config,
                                                                                std::string &config_type, const std::string &config_from,
                                                                                bool probe_type, std::string &error) {
         const auto *inherits = config.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS);
         if (!probe_type && (inherits == nullptr || inherits->value.empty()))
             return true;
 
-        std::unique_ptr<PresetBundle> source_bundle;
         PresetBundle                 *bundle = nullptr;
         bool                          allow_source_manifest = false;
         if (config_from == "system") {
-            source_bundle         = std::make_unique<PresetBundle>();
-            bundle                = source_bundle.get();
+            if (!system_preset_resolver)
+                system_preset_resolver = std::make_unique<PresetBundle>();
+            bundle                = system_preset_resolver.get();
             allow_source_manifest = true;
         } else {
             bundle = ensure_cli_preset_bundle(error);
@@ -3700,6 +3704,15 @@ int CLI::run(int argc, char **argv)
                 }
             }
 
+            // A mixed slot never reaches a nozzle, so its row and column stay empty, as in the GUI.
+            // Command line options are not merged into m_print_config yet, so they win here.
+            const ConfigOptionBools *is_mixed_opt = m_extra_config.option<ConfigOptionBools>("filament_is_mixed");
+            if (!is_mixed_opt)
+                is_mixed_opt = m_print_config.option<ConfigOptionBools>("filament_is_mixed");
+            auto is_mixed_slot = [is_mixed_opt](int idx) {
+                return is_mixed_opt && idx < static_cast<int>(is_mixed_opt->values.size()) && is_mixed_opt->values[idx];
+            };
+
             for (size_t nozzle_id = 0; nozzle_id < new_extruder_count; ++nozzle_id) {
             std::vector<double> flush_vol_mtx = get_flush_volumes_matrix(flush_vol_matrix, nozzle_id, new_extruder_count);
                 for (int from_idx = 0; from_idx < project_filament_count; from_idx++) {
@@ -3709,7 +3722,7 @@ int CLI::run(int argc, char **argv)
                     bool is_from_support = filament_is_support->get_at(from_idx);
                     for (int to_idx = 0; to_idx < project_filament_count; to_idx++) {
                         bool is_to_support = filament_is_support->get_at(to_idx);
-                        if (from_idx == to_idx) {
+                        if (from_idx == to_idx || is_mixed_slot(from_idx) || is_mixed_slot(to_idx)) {
                             flush_vol_mtx[project_filament_count * from_idx + to_idx] = 0.f;
                         } else {
                             int flushing_volume = 0;
@@ -3937,6 +3950,22 @@ int CLI::run(int argc, char **argv)
     // Normalizing after importing the 3MFs / AMFs
     m_print_config.normalize_fdm();
 
+    // A mixed slot is virtual but still needs a filament entry of its own. Without one, feature
+    // filament ids aimed at it fall outside the filament count, are reset to the first filament
+    // and the model silently prints in a single colour.
+    if (const auto *is_mixed_opt = m_print_config.option<ConfigOptionBools>("filament_is_mixed")) {
+        const auto &is_mixed = is_mixed_opt->values;
+        for (size_t slot = static_cast<size_t>(std::max(filament_count, 0)); slot < is_mixed.size(); ++slot) {
+            if (!is_mixed[slot])
+                continue;
+            BOOST_LOG_TRIVIAL(error) << boost::format("mixed filament slot %1% has no filament of its own, only %2% filaments are loaded; "
+                                                      "load one filament per slot, including each mixed one")
+                                            % (slot + 1) % filament_count;
+            record_exit_reson(outfile_dir, CLI_MIXED_FILAMENT_INVALID, 0, cli_errors[CLI_MIXED_FILAMENT_INVALID], sliced_info);
+            flush_and_exit(CLI_MIXED_FILAMENT_INVALID);
+        }
+    }
+
     m_print_config.option<ConfigOptionEnum<PrinterTechnology>>("printer_technology", true)->value = printer_technology;
 
     bool has_wipe_tower_position = m_print_config.option<ConfigOptionFloats>("wipe_tower_x") && m_print_config.option<ConfigOptionFloats>("wipe_tower_y");
@@ -3991,6 +4020,15 @@ int CLI::run(int argc, char **argv)
     bool is_smooth_timelapse = false;
     if (enable_timelapse && timelapse_type_opt && (timelapse_type_opt->getInt() == TimelapseType::tlSmooth))
         is_smooth_timelapse = true;
+    // A mixed filament swaps between its components every layer, so it needs the tower even when
+    // every loaded preset is the same.
+    if (disable_wipe_tower_after_mapping) {
+        if (const auto *is_mixed_opt = m_print_config.option<ConfigOptionBools>("filament_is_mixed");
+            is_mixed_opt && has_any_mixed_filament(is_mixed_opt->values)) {
+            disable_wipe_tower_after_mapping = false;
+            BOOST_LOG_TRIVIAL(info) << boost::format("%1%, set disable_wipe_tower_after_mapping back to false due to a mixed filament")%__LINE__;
+        }
+    }
     if (disable_wipe_tower_after_mapping) {
         if (is_smooth_timelapse)
         {
@@ -6197,6 +6235,36 @@ int CLI::run(int argc, char **argv)
                                 flush_and_exit(CLI_ONLY_ONE_TPU_SUPPORTED);
                             }
 
+                            // Same type gate as the GUI's Sidebar::has_broken_mixed_filament: refuse a plate that uses a
+                            // mixed slot whose components are different filament types. Missing or out-of-range
+                            // components never get here, validate() already rejects them for the whole project.
+                            const auto *is_mixed_opt   = m_print_config.option<ConfigOptionBools>("filament_is_mixed");
+                            const auto *components_opt = m_print_config.option<ConfigOptionStrings>("filament_mixed_components");
+                            if (is_mixed_opt && components_opt && has_any_mixed_filament(is_mixed_opt->values)) {
+                                const auto &is_mixed   = is_mixed_opt->values;
+                                const auto &components = components_opt->values;
+                                const size_t num_physical = static_cast<size_t>(filament_count) - static_cast<size_t>(std::count(is_mixed.begin(), is_mixed.end(), true));
+                                std::vector<std::string> physical_types(num_physical);
+                                for (size_t f_index = 0; f_index < num_physical; ++f_index) {
+                                    std::string displayed_type;
+                                    physical_types[f_index] = m_print_config.get_filament_type(displayed_type, static_cast<int>(f_index));
+                                    if (physical_types[f_index].empty())
+                                        physical_types[f_index] = "PLA";
+                                }
+                                const std::vector<size_t> mismatched_slots = check_mixed_filament_type_consistency(is_mixed, components, physical_types);
+                                // plate_filaments has mixed slots expanded to their components; the gate needs the slots.
+                                const std::vector<int> plate_slots = mismatched_slots.empty() ? std::vector<int>() :
+                                                                     part_plate->get_extruders_under_cli(true, m_print_config, false);
+                                for (size_t slot : mismatched_slots) {
+                                    if (std::find(plate_slots.begin(), plate_slots.end(), static_cast<int>(slot) + 1) == plate_slots.end())
+                                        continue;
+                                    BOOST_LOG_TRIVIAL(error) << boost::format("plate %1%: mixed filament %2% mixes components of different filament types")
+                                                                    % (index + 1) % (slot + 1);
+                                    record_exit_reson(outfile_dir, CLI_MIXED_FILAMENT_INVALID, index + 1, cli_errors[CLI_MIXED_FILAMENT_INVALID], sliced_info);
+                                    flush_and_exit(CLI_MIXED_FILAMENT_INVALID);
+                                }
+                            }
+
                             if (new_extruder_count > 1) {
                                 std::vector<std::vector<int>> unprintable_filament_vec;
                                 for (const std::set<int>& filamnt_ids : unprintable_filament_ids) {

src/libslic3r/PresetBundle.cpp

@@ -549,30 +549,11 @@ bool PresetBundle::resolve_preset_config(DynamicPrintConfig &config, Preset::Typ
             continue;
 
         try {
-            PresetBundle library_bundle;
-            const PresetBundle *base_bundle = nullptr;
-            if (vendor_id != ORCA_FILAMENT_LIBRARY &&
-                boost::filesystem::is_regular_file(root_dir / (std::string(ORCA_FILAMENT_LIBRARY) + ".json"))) {
-                library_bundle.m_preserve_vendor_source_paths = true;
-                library_bundle.load_vendor_configs_from_json(root_dir.string(), ORCA_FILAMENT_LIBRARY, LoadSystem,
-                                                             compatibility_rule, nullptr, false);
-                if (library_bundle.error_count() != 0) {
-                    error = "OrcaFilamentLibrary contains invalid presets";
-                    return false;
-                }
-                base_bundle = &library_bundle;
-            }
-
-            PresetBundle source_bundle;
-            source_bundle.m_preserve_vendor_source_paths = true;
-            source_bundle.load_vendor_configs_from_json(root_dir.string(), vendor_id, LoadSystem,
-                                                        compatibility_rule, base_bundle, false);
-            if (source_bundle.error_count() != 0) {
-                error = "Vendor bundle contains invalid presets";
+            const SourceManifestBundles *loaded = load_source_manifest(root_dir, vendor_id, compatibility_rule, error);
+            if (loaded == nullptr)
                 return false;
-            }
 
-            const Preset *resolved = find_loaded(source_bundle);
+            const Preset *resolved = find_loaded(*loaded->vendor);
             if (resolved == nullptr) {
                 if (error.empty())
                     error = "Source file is not an instantiated preset in its vendor manifest";
@@ -591,6 +572,39 @@ bool PresetBundle::resolve_preset_config(DynamicPrintConfig &config, Preset::Typ
     return false;
 }
 
+const PresetBundle::SourceManifestBundles *PresetBundle::load_source_manifest(const boost::filesystem::path &root_dir,
+                                                                            const std::string &vendor_id,
+                                                                            ForwardCompatibilitySubstitutionRule compatibility_rule,
+                                                                            std::string &error)
+{
+    auto key = std::make_tuple(root_dir.string(), vendor_id, static_cast<int>(compatibility_rule));
+    if (auto it = m_source_manifest_bundles.find(key); it != m_source_manifest_bundles.end())
+        return &it->second;
+
+    SourceManifestBundles loaded;
+    if (vendor_id != ORCA_FILAMENT_LIBRARY &&
+        boost::filesystem::is_regular_file(root_dir / (std::string(ORCA_FILAMENT_LIBRARY) + ".json"))) {
+        loaded.library = std::make_unique<PresetBundle>();
+        loaded.library->m_preserve_vendor_source_paths = true;
+        loaded.library->load_vendor_configs_from_json(root_dir.string(), ORCA_FILAMENT_LIBRARY, LoadSystem,
+                                                      compatibility_rule, nullptr, false);
+        if (loaded.library->error_count() != 0) {
+            error = "OrcaFilamentLibrary contains invalid presets";
+            return nullptr;
+        }
+    }
+
+    loaded.vendor = std::make_unique<PresetBundle>();
+    loaded.vendor->m_preserve_vendor_source_paths = true;
+    loaded.vendor->load_vendor_configs_from_json(root_dir.string(), vendor_id, LoadSystem,
+                                                 compatibility_rule, loaded.library.get(), false);
+    if (loaded.vendor->error_count() != 0) {
+        error = "Vendor bundle contains invalid presets";
+        return nullptr;
+    }
+    return &m_source_manifest_bundles.emplace(std::move(key), std::move(loaded)).first->second;
+}
+
 bool PresetBundle::resolve_preset_config_type(DynamicPrintConfig &config, Preset::Type &type,
                                               const std::string &source_file,
                                               ForwardCompatibilitySubstitutionRule compatibility_rule,

src/libslic3r/PresetBundle.hpp

@@ -11,6 +11,7 @@
 #include <map>
 #include <set>
 #include <shared_mutex>
+#include <tuple>
 #include <unordered_map>
 #include <optional>
 #include <array>
@@ -652,6 +653,19 @@ private:
     bool m_generate_vendor_caches { false };
     bool m_preserve_vendor_source_paths { false };
 
+    // Vendor trees loaded by resolve_preset_config's manifest path, so every preset
+    // resolved through this bundle shares one load per source root and vendor.
+    struct SourceManifestBundles {
+        std::unique_ptr<PresetBundle> library;
+        std::unique_ptr<PresetBundle> vendor;
+    };
+    std::map<std::tuple<std::string, std::string, int>, SourceManifestBundles> m_source_manifest_bundles;
+
+    const SourceManifestBundles *load_source_manifest(const boost::filesystem::path &root_dir,
+                                                      const std::string &vendor_id,
+                                                      ForwardCompatibilitySubstitutionRule compatibility_rule,
+                                                      std::string &error);
+
     // Orca: validation only - flag any printer with two or more compatible
     // filament presets sharing one filament_id (ambiguous AMS subtype match).
     bool check_duplicate_filament_subtypes() const;

src/libslic3r/PrintConfig.cpp

@@ -10936,6 +10936,28 @@ std::vector<int> DynamicPrintConfig::update_values_to_printer_extruders(DynamicP
     return variant_index;
 }
 
+// Regathers a vector option's values through per-slot source indices (one input index per
+// output slot). Out-of-range indices keep the first value, matching get_at's fallback.
+template<typename OptType, typename ValueType>
+static void gather_option_values(const char *caller, const std::string &key, OptType *opt, const std::vector<int> &slot_param_indices)
+{
+    if (!opt || opt->values.empty()) {
+        BOOST_LOG_TRIVIAL(warning) << caller << boost::format(", Line %1%: option %2% not found or empty, skipping")%__LINE__%key;
+        return;
+    }
+    std::vector<ValueType> new_values;
+    new_values.reserve(slot_param_indices.size());
+    for (int idx : slot_param_indices) {
+        if (idx < 0 || static_cast<size_t>(idx) >= opt->values.size()) {
+            BOOST_LOG_TRIVIAL(warning) << caller << boost::format(", Line %1%: option %2% slot index %3% out of range, keeping first value")%__LINE__%key%idx;
+            new_values.emplace_back(opt->values.front());
+        }
+        else
+            new_values.emplace_back(opt->values[idx]);
+    }
+    opt->values = std::move(new_values);
+}
+
 void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filaments(DynamicPrintConfig& printer_config, int extruder_count, int extruder_nozzle_volume_count, std::set<std::string>& key_set, std::string id_name, std::string variant_name)
 {
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(", Line %1%: extruder_count %2%, extruder_nozzle_volume_count %3%")%__LINE__ %extruder_count %extruder_nozzle_volume_count;
@@ -11013,155 +11035,18 @@ void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filamen
                 BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: can not find opt define for %2%")%__LINE__%key;
                 continue;
             }
+            // An empty option has no first value to fall back on; give it one registered default per filament.
+            if (auto *vec = dynamic_cast<ConfigOptionVectorBase*>(this->option(key)); vec && vec->empty() && optdef->default_value)
+                vec->resize(filament_count, optdef->default_value.get());
 
             switch (optdef->type) {
-                case coStrings:
-                {
-                    ConfigOptionStrings * opt = this->option<ConfigOptionStrings>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<std::string> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coInts:
-                {
-                    ConfigOptionInts * opt = this->option<ConfigOptionInts>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<int> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coFloats:
-                {
-                    ConfigOptionFloats * opt = this->option<ConfigOptionFloats>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<double> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coPercents:
-                {
-                    ConfigOptionPercents * opt = this->option<ConfigOptionPercents>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<double> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coFloatsOrPercents:
-                {
-                    ConfigOptionFloatsOrPercents * opt = this->option<ConfigOptionFloatsOrPercents>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<FloatOrPercent> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coBools:
-                {
-                    ConfigOptionBools * opt = this->option<ConfigOptionBools>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<unsigned char> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coEnums:
-                {
-                    ConfigOptionEnumsGeneric * opt = this->option<ConfigOptionEnumsGeneric>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<int> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
+                case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(__FUNCTION__, key, this->option<ConfigOptionStrings>(key), variant_index); break;
+                case coInts:             gather_option_values<ConfigOptionInts, int>(__FUNCTION__, key, this->option<ConfigOptionInts>(key), variant_index); break;
+                case coFloats:           gather_option_values<ConfigOptionFloats, double>(__FUNCTION__, key, this->option<ConfigOptionFloats>(key), variant_index); break;
+                case coPercents:         gather_option_values<ConfigOptionPercents, double>(__FUNCTION__, key, this->option<ConfigOptionPercents>(key), variant_index); break;
+                case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(__FUNCTION__, key, this->option<ConfigOptionFloatsOrPercents>(key), variant_index); break;
+                case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(__FUNCTION__, key, this->option<ConfigOptionBools>(key), variant_index); break;
+                case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(__FUNCTION__, key, this->option<ConfigOptionEnumsGeneric>(key), variant_index); break;
                 default:
                     BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: unsupported option type for %2%")%__LINE__%key;
                     break;
@@ -11180,28 +11065,6 @@ void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filamen
     }
 }
 
-// Regathers a vector option's values through per-slot source indices (one input index per
-// output slot). Out-of-range indices keep the first value, matching get_at's fallback.
-template<typename OptType, typename ValueType>
-static void gather_option_values(const std::string &key, OptType *opt, const std::vector<int> &slot_param_indices)
-{
-    if (!opt || opt->values.empty()) {
-        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found or empty, skipping")%__LINE__%key;
-        return;
-    }
-    std::vector<ValueType> new_values;
-    new_values.reserve(slot_param_indices.size());
-    for (int idx : slot_param_indices) {
-        if (idx < 0 || static_cast<size_t>(idx) >= opt->values.size()) {
-            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% slot index %3% out of range, keeping first value")%__LINE__%key%idx;
-            new_values.emplace_back(opt->values.front());
-        }
-        else
-            new_values.emplace_back(opt->values[idx]);
-    }
-    opt->values = std::move(new_values);
-}
-
 void DynamicPrintConfig::update_filament_config_values_for_multiple_extruders(DynamicPrintConfig& printer_config,
     const std::unordered_map<int, std::vector<FilamentVariantUse>>& filament_variant_uses,
     int extruder_count, int extruder_nozzle_volume_count,
@@ -11296,13 +11159,13 @@ void DynamicPrintConfig::update_filament_config_values_for_multiple_extruders(Dy
             continue;
         }
         switch (optdef->type) {
-            case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(key, this->option<ConfigOptionStrings>(key), slot_param_indices); break;
-            case coInts:             gather_option_values<ConfigOptionInts, int>(key, this->option<ConfigOptionInts>(key), slot_param_indices); break;
-            case coFloats:           gather_option_values<ConfigOptionFloats, double>(key, this->option<ConfigOptionFloats>(key), slot_param_indices); break;
-            case coPercents:         gather_option_values<ConfigOptionPercents, double>(key, this->option<ConfigOptionPercents>(key), slot_param_indices); break;
-            case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(key, this->option<ConfigOptionFloatsOrPercents>(key), slot_param_indices); break;
-            case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(key, this->option<ConfigOptionBools>(key), slot_param_indices); break;
-            case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(key, this->option<ConfigOptionEnumsGeneric>(key), slot_param_indices); break;
+            case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(__FUNCTION__, key, this->option<ConfigOptionStrings>(key), slot_param_indices); break;
+            case coInts:             gather_option_values<ConfigOptionInts, int>(__FUNCTION__, key, this->option<ConfigOptionInts>(key), slot_param_indices); break;
+            case coFloats:           gather_option_values<ConfigOptionFloats, double>(__FUNCTION__, key, this->option<ConfigOptionFloats>(key), slot_param_indices); break;
+            case coPercents:         gather_option_values<ConfigOptionPercents, double>(__FUNCTION__, key, this->option<ConfigOptionPercents>(key), slot_param_indices); break;
+            case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(__FUNCTION__, key, this->option<ConfigOptionFloatsOrPercents>(key), slot_param_indices); break;
+            case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(__FUNCTION__, key, this->option<ConfigOptionBools>(key), slot_param_indices); break;
+            case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(__FUNCTION__, key, this->option<ConfigOptionEnumsGeneric>(key), slot_param_indices); break;
             default:
                 BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: unsupported option type for %2%")%__LINE__%key;
                 break;

src/libslic3r/Utils.hpp

@@ -70,6 +70,7 @@
 #define CLI_FILAMENT_CAN_NOT_MAP      -66
 #define CLI_ONLY_ONE_TPU_SUPPORTED      -67
 #define CLI_FILAMENTS_NOT_SUPPORTED_BY_EXTRUDER  -68
+#define CLI_MIXED_FILAMENT_INVALID      -69
 
 #define CLI_SLICING_ERROR                  -100
 #define CLI_GCODE_PATH_CONFLICTS           -101

src/slic3r/GUI/PartPlate.cpp

@@ -1717,7 +1717,7 @@ std::vector<int> PartPlate::get_extruders(bool conside_custom_gcode, const Dynam
 	return plate_extruders;
 }
 
-std::vector<int> PartPlate::get_extruders_under_cli(bool conside_custom_gcode, DynamicPrintConfig& full_config) const
+std::vector<int> PartPlate::get_extruders_under_cli(bool conside_custom_gcode, DynamicPrintConfig& full_config, bool expand_mixed_slots) const
 {
     std::vector<int> plate_extruders;
 
@@ -1878,7 +1878,7 @@ std::vector<int> PartPlate::get_extruders_under_cli(bool conside_custom_gcode, D
     // Expand mixed filament slots to their physical components. A mixed slot is virtual and
     // is never loaded into a tray, so callers (AMS mapping, filament checks) must see the
     // physical filaments it resolves to instead.
-    {
+    if (expand_mixed_slots) {
         auto* is_mixed_opt = full_config.option<ConfigOptionBools>("filament_is_mixed");
         auto* comp_strs_opt = full_config.option<ConfigOptionStrings>("filament_mixed_components");
         if (is_mixed_opt && comp_strs_opt && has_any_mixed_filament(is_mixed_opt->values)) {

src/slic3r/GUI/PartPlate.hpp

@@ -350,7 +350,8 @@ public:
     // get used filaments from config, 1 based idx
     std::vector<int> get_extruders(bool conside_custom_gcode = false) const;
     std::vector<int> get_extruders(bool conside_custom_gcode, const DynamicPrintConfig& glb_config, const DynamicPrintConfig& project_config) const;
-    std::vector<int> get_extruders_under_cli(bool conside_custom_gcode, DynamicPrintConfig& full_config) const;
+    // expand_mixed_slots = false keeps mixed filament slots as slots instead of their components.
+    std::vector<int> get_extruders_under_cli(bool conside_custom_gcode, DynamicPrintConfig& full_config, bool expand_mixed_slots = true) const;
     std::vector<int> get_extruders_without_support(bool conside_custom_gcode = false) const;
     // get used filaments from gcode result, 1 based idx
     std::vector<int> get_used_filaments();

tests/libslic3r/test_config_variant_expansion.cpp

@@ -484,6 +484,34 @@ TEST_CASE("update_values_to_printer_extruders_for_multiple_filaments resolves pe
         REQUIRE(config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values == std::vector<double>({12., 21.}));
         REQUIRE(config.option<ConfigOptionInts>("filament_self_index")->values == std::vector<int>({1, 2}));
     }
+
+    SECTION("a variant option shorter than the filament slots keeps its first value instead of zero") {
+        DynamicPrintConfig config;
+        config.option<ConfigOptionEnumsGeneric>("extruder_type", true)->values = {etDirectDrive, etDirectDrive};
+        config.option<ConfigOptionEnumsGeneric>("nozzle_volume_type", true)->values = {nvtStandard, nvtHighFlow};
+        config.option<ConfigOptionStrings>("extruder_variant_list", true)->values = {"Direct Drive Standard,Direct Drive High Flow",
+                                                                                     "Direct Drive Standard,Direct Drive High Flow"};
+        make_filament_arrays(config);
+        config.option<ConfigOptionInts>("filament_map", true)->values = {1, 2};
+        // no loaded preset carries the key, so only its single registered default is present
+        config.option<ConfigOptionFloatsNullable>("filament_cooling_before_tower", true)->values = {10.};
+        // only the first filament's two variant columns were loaded
+        config.option<ConfigOptionFloatsNullable>("filament_ramming_volumetric_speed", true)->values = {-1., -2.};
+
+        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
+        int extruder_count = 2;
+        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
+
+        config.update_values_to_printer_extruders_for_multiple_filaments(config, extruder_count, count, filament_keys,
+            "filament_self_index", "filament_extruder_variant");
+
+        // filament 2 resolves to column 3 (its extruder's High Flow column), past the end of both vectors
+        REQUIRE_THAT(config.option<ConfigOptionFloatsNullable>("filament_cooling_before_tower")->values,
+                     Catch::Matchers::Approx(std::vector<double>({10., 10.})));
+        REQUIRE_THAT(config.option<ConfigOptionFloatsNullable>("filament_ramming_volumetric_speed")->values,
+                     Catch::Matchers::Approx(std::vector<double>({-1., -1.})));
+        REQUIRE(config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values == std::vector<double>({12., 21.}));
+    }
 }
 
 // update_values_from_multi_to_multi_2 walks the DESTINATION PRINTER's variant list while writing

tests/libslic3r/test_preset_bundle_loading.cpp

@@ -987,6 +987,137 @@ TEST_CASE("Resolution terminates when no vendor manifest exists", "[Preset][Bund
     CHECK(error == "Preset was not found in the loaded bundle");
 }
 
+TEST_CASE("Manifest-backed resolution reuses the vendor tree it already loaded", "[Preset][Bundle][Regression]")
+{
+    ScopedTemporaryDir dir;
+    const fs::path      process_dir = dir.path() / "Acme" / "process";
+    fs::create_directories(process_dir);
+    std::ofstream((dir.path() / "Acme.json").string())
+        << R"({"version":"1.0.0","name":"Acme","process_list":[)"
+        << R"({"name":"fdm_process_common","sub_path":"process/base.json"},)"
+        << R"({"name":"Acme First","sub_path":"process/first.json"},)"
+        << R"({"name":"Acme Second","sub_path":"process/second.json"}]})";
+    auto write_base = [&](double travel_speed) {
+        std::ofstream((process_dir / "base.json").string())
+            << R"({"type":"process","name":"fdm_process_common","from":"system",)"
+            << R"("instantiation":"false","travel_speed":[")" << travel_speed << R"("]})";
+    };
+    auto write_child = [&](const std::string &file, const std::string &name) {
+        std::ofstream((process_dir / file).string())
+            << R"({"type":"process","name":")" << name << R"(","from":"system",)"
+            << R"("instantiation":"true","inherits":"fdm_process_common"})";
+    };
+    write_base(111.0);
+    write_child("first.json", "Acme First");
+    write_child("second.json", "Acme Second");
+
+    auto travel_speed = [&](PresetBundle &bundle, const std::string &file) {
+        DynamicPrintConfig raw;
+        raw.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS, true)->value = "fdm_process_common";
+        std::string error;
+        REQUIRE(bundle.resolve_preset_config(raw, Preset::TYPE_PRINT, (process_dir / file).string(),
+                                             ForwardCompatibilitySubstitutionRule::EnableSilent, error));
+        return raw.option<ConfigOptionFloats>("travel_speed")->values.front();
+    };
+
+    PresetBundle bundle;
+    CHECK_THAT(travel_speed(bundle, "first.json"), Catch::Matchers::WithinAbs(111.0, 1e-6));
+
+    // Only a reload would see this change.
+    write_base(222.0);
+    CHECK_THAT(travel_speed(bundle, "second.json"), Catch::Matchers::WithinAbs(111.0, 1e-6));
+
+    PresetBundle fresh;
+    CHECK_THAT(travel_speed(fresh, "second.json"), Catch::Matchers::WithinAbs(222.0, 1e-6));
+}
+
+TEST_CASE("Manifest-backed resolution does not keep a vendor tree that failed to load", "[Preset][Bundle][Regression]")
+{
+    ScopedTemporaryDir dir;
+    const fs::path      child_file = dir.path() / "Acme" / "process" / "child.json";
+    auto write_manifest = [&](const std::string &leading_entry) {
+        std::ofstream((dir.path() / "Acme.json").string())
+            << R"({"version":"1.0.0","name":"Acme","process_list":[)" << leading_entry
+            << R"({"name":"Acme Process","sub_path":"process/child.json"}]})";
+    };
+    write_manifest("123,");
+    fs::create_directories(child_file.parent_path());
+    std::ofstream(child_file.string())
+        << R"({"type":"process","name":"Acme Process","from":"system",)"
+        << R"("instantiation":"true","layer_height":"0.2"})";
+
+    PresetBundle bundle;
+    auto resolve = [&](std::string &error) {
+        DynamicPrintConfig raw;
+        raw.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS, true)->value = "fdm_process_common";
+        return bundle.resolve_preset_config(raw, Preset::TYPE_PRINT, child_file.string(),
+                                            ForwardCompatibilitySubstitutionRule::EnableSilent, error);
+    };
+
+    std::string error;
+    CHECK_FALSE(resolve(error));
+    CHECK_FALSE(error.empty());
+
+    write_manifest("");
+    error.clear();
+    CHECK(resolve(error));
+    CHECK(error.empty());
+}
+
+TEST_CASE("Manifest-backed resolution reuses the library base for type-probed files", "[Preset][Bundle][Regression]")
+{
+    ScopedTemporaryDir dir;
+    const fs::path      library_pet  = dir.path() / PresetBundle::ORCA_FILAMENT_LIBRARY / "filament" / "pet.json";
+    const fs::path      filament_dir = dir.path() / "Acme" / "filament";
+
+    std::ofstream((dir.path() / (std::string(PresetBundle::ORCA_FILAMENT_LIBRARY) + ".json")).string())
+        << R"({"version":"1.0.0","name":"OrcaFilamentLibrary","filament_list":[)"
+        << R"({"name":"fdm_filament_pet","sub_path":"filament/pet.json","filament_id":"GFL99"}]})";
+    fs::create_directories(library_pet.parent_path());
+    auto write_library_pet = [&](double density) {
+        std::ofstream(library_pet.string())
+            << R"({"type":"filament","name":"fdm_filament_pet","from":"system",)"
+            << R"("filament_id":"GFL99","instantiation":"false",)"
+            << R"("filament_type":["PETG"],"filament_density":[")" << density << R"("]})";
+    };
+    write_library_pet(1.27);
+
+    std::ofstream((dir.path() / "Acme.json").string())
+        << R"({"version":"1.0.0","name":"Acme","filament_list":[)"
+        << R"({"name":"Acme PETG","sub_path":"filament/petg.json","filament_id":"GFA00"},)"
+        << R"({"name":"Acme PETG Matte","sub_path":"filament/petg_matte.json","filament_id":"GFA01"}]})";
+    fs::create_directories(filament_dir);
+    auto write_child = [&](const std::string &file, const std::string &name, const std::string &filament_id) {
+        std::ofstream((filament_dir / file).string())
+            << R"({"type":"filament","name":")" << name << R"(","from":"system",)"
+            << R"("filament_id":")" << filament_id << R"(","instantiation":"true","inherits":"fdm_filament_pet"})";
+    };
+    write_child("petg.json", "Acme PETG", "GFA00");
+    write_child("petg_matte.json", "Acme PETG Matte", "GFA01");
+
+    auto density = [](const DynamicPrintConfig &config) {
+        return config.option<ConfigOptionFloats>("filament_density")->values.front();
+    };
+
+    PresetBundle       bundle;
+    DynamicPrintConfig first;
+    first.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS, true)->value = "fdm_filament_pet";
+    std::string error;
+    REQUIRE(bundle.resolve_preset_config(first, Preset::TYPE_FILAMENT, (filament_dir / "petg.json").string(),
+                                         ForwardCompatibilitySubstitutionRule::EnableSilent, error));
+    CHECK_THAT(density(first), Catch::Matchers::WithinAbs(1.27, 1e-6));
+
+    // Only a reload would see this change.
+    write_library_pet(1.5);
+
+    DynamicPrintConfig second;
+    Preset::Type       type = Preset::TYPE_INVALID;
+    REQUIRE(bundle.resolve_preset_config_type(second, type, (filament_dir / "petg_matte.json").string(),
+                                              ForwardCompatibilitySubstitutionRule::EnableSilent, error));
+    CHECK(type == Preset::TYPE_FILAMENT);
+    CHECK_THAT(density(second), Catch::Matchers::WithinAbs(1.27, 1e-6));
+}
+
 // Orca: a filament in the Orca Filament Library that names its compatible printers has to hide the generic
 // library filament sharing its alias, the same way a vendor owned filament does. Otherwise both are compatible
 // with that printer and the plater combo box lists the shared alias twice.