Keep a Project's Changed Values on Extruder Variants It Doesn't List

A project's listed settings are carried onto its base preset by update_non_diff_values_to_base_config, which matched variants by exact name and id. A variant the base gained after the project was saved got the base's value, while the same value in a user preset now falls back to the preset's first variant of that extruder. So an old project opened with its printer preset already modified, and saving it wrote the base's values into the 3MF.

The function now maps variants with map_variant_indices, as update_diff_values_to_child_config does: a base variant the project does not list takes the project's first variant of the same extruder. The variant lists themselves stay the base's, so a fallback never writes one variant's name over another's.

src/libslic3r/PrintConfig.cpp

@@ -11513,12 +11513,18 @@ void DynamicPrintConfig::update_non_diff_values_to_base_config(DynamicPrintConfi
     int cur_variant_count = cur_extruder_variants.size();
     int target_variant_count = target_extruder_variants.size();
 
+    // A base variant this config does not list (the base gained it after the config was saved, or the
+    // config lists none) takes this config's first variant of the same extruder, as a user preset's
+    // values do in update_diff_values_to_child_config. Left unmatched, the base's value would silently
+    // replace the user's.
     variant_index.resize(target_variant_count, -1);
     if (cur_variant_count == 0) {
         // Defensive: target_variant_count may be 0 if the preset doesn't carry extruder_variant_name.
         // In that case keep variant_index empty and let the downstream size checks produce a useful error.
         if (!variant_index.empty())
-            variant_index[0] = 0;
+            // This config's one value belongs to the extruder of the base's first variant.
+            variant_index = map_variant_indices(target_extruder_variants, target_extruder_ids, {},
+                                                target_extruder_ids.empty() ? std::vector<int>() : std::vector<int>{target_extruder_ids[0]});
     }
     else if ((cur_extruder_ids.size() > 0) && cur_variant_count != cur_extruder_ids.size()){
         //should not happen
@@ -11531,18 +11537,7 @@ void DynamicPrintConfig::update_non_diff_values_to_base_config(DynamicPrintConfi
              %extruder_variant_name %target_variant_count %extruder_id_name %target_extruder_ids.size();
     }
     else {
-        for (int i = 0; i < target_variant_count; i++)
-        {
-            for (int j = 0; j < cur_variant_count; j++)
-            {
-                if ((target_extruder_variants[i] == cur_extruder_variants[j])
-                    &&(target_extruder_ids.empty() || (target_extruder_ids[i] == cur_extruder_ids[j])))
-                {
-                    variant_index[i] = j;
-                    break;
-                }
-            }
-        }
+        variant_index = map_variant_indices(target_extruder_variants, target_extruder_ids, cur_extruder_variants, cur_extruder_ids);
     }
 
     for (auto& opt : keys) {
@@ -11567,6 +11562,13 @@ void DynamicPrintConfig::update_non_diff_values_to_base_config(DynamicPrintConfi
                     if (cur_variant_count > target_variant_count)
                         continue;
 
+                    // The variant lists are the base's layout itself, which every other value is
+                    // carried onto: a variant this config lacks keeps its own name and id.
+                    if (opt == extruder_id_name || opt == extruder_variant_name) {
+                        opt_src->set(opt_target);
+                        continue;
+                    }
+
                     int stride = 1;
                     if (key_set2.find(opt) != key_set2.end())
                         stride = 2;

tests/libslic3r/test_config.cpp

@@ -536,6 +536,110 @@ SCENARIO("update_diff_values_to_child_config keeps a child's values on variants
     }
 }
 
+SCENARIO("update_non_diff_values_to_base_config keeps a project's changed values on variants it does not list",
+         "[Config][Variant]") {
+    std::set<std::string> no_keys;
+    auto variants = [](std::initializer_list<std::string> names) { return new Slic3r::ConfigOptionStrings(names); };
+
+    GIVEN("A filament base with three variants") {
+        Slic3r::DynamicPrintConfig base;
+        base.set_key_value("filament_extruder_variant",
+            variants({"Direct Drive Standard", "Bowden Standard", "Direct Drive High Flow"}));
+        base.set_deserialize_strict("nozzle_temperature", "220,220,220");
+
+        WHEN("the project was saved when the base had only its first variant") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_key_value("filament_extruder_variant", variants({"Direct Drive Standard"}));
+            project.set_deserialize_strict("nozzle_temperature", "199");
+
+            AND_WHEN("the project lists the value as changed") {
+                project.update_non_diff_values_to_base_config(base, project.keys(), {"nozzle_temperature"}, "", "filament_extruder_variant",
+                                                              Slic3r::filament_options_with_variant, no_keys);
+                THEN("the project's value applies to every variant") {
+                    REQUIRE(project.opt_serialize("nozzle_temperature") == "199,199,199");
+                }
+            }
+            AND_WHEN("the project does not list the value as changed") {
+                project.update_non_diff_values_to_base_config(base, project.keys(), {}, "", "filament_extruder_variant",
+                                                              Slic3r::filament_options_with_variant, no_keys);
+                THEN("the base's values replace it") {
+                    REQUIRE(project.opt_serialize("nozzle_temperature") == "220,220,220");
+                }
+            }
+        }
+        WHEN("the project lists every variant, in another order") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_key_value("filament_extruder_variant",
+                variants({"Bowden Standard", "Direct Drive High Flow", "Direct Drive Standard"}));
+            project.set_deserialize_strict("nozzle_temperature", "190,205,199");
+            project.update_non_diff_values_to_base_config(base, project.keys(), {"nozzle_temperature"}, "", "filament_extruder_variant",
+                                                          Slic3r::filament_options_with_variant, no_keys);
+            THEN("each variant keeps its own value") {
+                REQUIRE(project.opt_serialize("nozzle_temperature") == "199,190,205");
+            }
+        }
+        WHEN("the project lists no variants") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_deserialize_strict("nozzle_temperature", "199");
+            project.update_non_diff_values_to_base_config(base, project.keys(), {"nozzle_temperature"}, "", "filament_extruder_variant",
+                                                          Slic3r::filament_options_with_variant, no_keys);
+            THEN("the project's value applies to every variant") {
+                REQUIRE(project.opt_serialize("nozzle_temperature") == "199,199,199");
+            }
+        }
+    }
+
+    GIVEN("A two-extruder printer base with two variants per extruder") {
+        Slic3r::DynamicPrintConfig base;
+        base.set_key_value("printer_extruder_variant",
+            variants({"Direct Drive Standard", "Direct Drive High Flow", "Direct Drive Standard", "Direct Drive High Flow"}));
+        base.set_key_value("printer_extruder_id", new Slic3r::ConfigOptionInts({1, 1, 2, 2}));
+        base.set_deserialize_strict("retraction_length", "0.8,0.8,0.8,0.8");
+
+        WHEN("the project lists only the Standard variant of each extruder") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_key_value("printer_extruder_variant", variants({"Direct Drive Standard", "Direct Drive Standard"}));
+            project.set_key_value("printer_extruder_id", new Slic3r::ConfigOptionInts({1, 2}));
+            project.set_deserialize_strict("retraction_length", "1.1,2.2");
+            project.update_non_diff_values_to_base_config(base, project.keys(), {"retraction_length"}, "printer_extruder_id", "printer_extruder_variant",
+                                                          Slic3r::printer_options_with_variant_1,
+                                                          Slic3r::printer_options_with_variant_2);
+            THEN("each extruder's High Flow variant takes that extruder's value") {
+                REQUIRE(project.opt_serialize("retraction_length") == "1.1,1.1,2.2,2.2");
+            }
+        }
+        WHEN("the project lists only the Standard variant of each extruder, and the variant lists as changed") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_key_value("printer_extruder_variant", variants({"Direct Drive Standard", "Direct Drive Standard"}));
+            project.set_key_value("printer_extruder_id", new Slic3r::ConfigOptionInts({1, 2}));
+            project.set_deserialize_strict("machine_max_speed_x", "300,100,400,150");
+            base.set_deserialize_strict("machine_max_speed_x", "500,200,500,200,500,200,500,200");
+            project.update_non_diff_values_to_base_config(base, project.keys(),
+                                                          {"machine_max_speed_x", "printer_extruder_id", "printer_extruder_variant"},
+                                                          "printer_extruder_id", "printer_extruder_variant",
+                                                          Slic3r::printer_options_with_variant_1,
+                                                          Slic3r::printer_options_with_variant_2);
+            THEN("the variant lists are the base's") {
+                REQUIRE(project.opt_serialize("printer_extruder_variant") == base.opt_serialize("printer_extruder_variant"));
+                REQUIRE(project.opt_serialize("printer_extruder_id") == "1,1,2,2");
+            }
+            THEN("each extruder's High Flow variant takes that extruder's pair of limits") {
+                REQUIRE(project.opt_serialize("machine_max_speed_x") == "300,100,300,100,400,150,400,150");
+            }
+        }
+        WHEN("the project lists no variants") {
+            Slic3r::DynamicPrintConfig project;
+            project.set_deserialize_strict("retraction_length", "1.1");
+            project.update_non_diff_values_to_base_config(base, project.keys(), {"retraction_length"}, "printer_extruder_id", "printer_extruder_variant",
+                                                          Slic3r::printer_options_with_variant_1,
+                                                          Slic3r::printer_options_with_variant_2);
+            THEN("only the first extruder's variants take the project's value") {
+                REQUIRE(project.opt_serialize("retraction_length") == "1.1,1.1,0.8,0.8");
+            }
+        }
+    }
+}
+
 // SCENARIO("DynamicPrintConfig JSON serialization", "[Config]") {
 //     WHEN("DynamicPrintConfig is serialized and deserialized") {
 // 	auto now = std::chrono::high_resolution_clock::now();

tests/libslic3r/test_preset_bundle_loading.cpp

@@ -6081,8 +6081,9 @@ TEST_CASE("A per-variant project value maps onto its base preset's variant layou
                                                                    base_finder(&base, calls));
     CHECK(config.option<ConfigOptionStrings>("print_extruder_variant")->values ==
           std::vector<std::string>{"Direct Drive Standard", "Direct Drive High Flow"});
-    // The listed key keeps the project's Standard value and takes High Flow from the base.
-    check_double_vector(config.option<ConfigOptionFloats>("outer_wall_speed")->values, {100., 300.});
+    // The listed key keeps the project's Standard value, and High Flow, which the project does not
+    // list, takes it too, as a user preset's value does.
+    check_double_vector(config.option<ConfigOptionFloats>("outer_wall_speed")->values, {100., 100.});
     check_double_vector(config.option<ConfigOptionFloats>("inner_wall_speed")->values, {250., 350.});
 }