Fix crash when opening a G-code file exported by OrcaSlicer (#16441)

src/libslic3r/GCode/GCodeProcessor.cpp

@@ -3752,7 +3752,8 @@ DynamicConfig GCodeProcessor::export_config_for_render() const
     config.set_key_value("filament_is_support", new ConfigOptionBools(m_parser.get_config().filament_is_support.values));
     config.set_key_value("filament_type", new ConfigOptionStrings(m_parser.get_config().filament_type.values));
     config.set_key_value("filament_map", new ConfigOptionInts(m_parser.get_config().filament_map.values));
-    config.apply(m_belt_render_config);
+    // += clones the options; apply() would need a definition this config does not have.
+    config += m_belt_render_config;
     return config;
 }
 

tests/fff_print/test_gcode_processor.cpp

@@ -2,14 +2,19 @@
 
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/GCode/GCodeProcessor.hpp"
+#include "libslic3r/Model.hpp"
+#include "libslic3r/Print.hpp"
 #include "libslic3r/PrintConfig.hpp"
 
 #include "test_utils.hpp"
 
 #include <cstddef>
 #include <fstream>
+#include <initializer_list>
 #include <string>
+#include <catch2/catch_message.hpp>
 #include <catch2/catch_test_macros.hpp>
+#include <catch2/generators/catch_generators.hpp>
 #include <catch2/matchers/catch_matchers.hpp>
 #include <catch2/matchers/catch_matchers_floating_point.hpp>
 
@@ -49,6 +54,74 @@ TEST_CASE("The belt header's angle marks G-code as belt G-code", "[GCodeProcesso
     CHECK_THAT(processed_belt_tilt(gcode), WithinAbs(45., 1e-6));
 }
 
+TEST_CASE("A loaded G-code's belt settings and bed replace the selected printer's in the preview", "[GCodeProcessor][belt][Regression]")
+{
+    // Loading a G-code applies the selected printer's config to the Print, then the file's render
+    // config on top, so the preview's belt view and back-transform follow the file. The selected
+    // printer is always the other kind, and every belt and bed key differs between the two.
+    const bool file_is_belt = GENERATE(false, true);
+    CAPTURE(file_is_belt);
+
+    DynamicPrintConfig file = DynamicPrintConfig::full_print_config();
+    file.set_deserialize_strict({
+        { "belt_printer",              file_is_belt },
+        { "belt_slice_rotation",       "y" },
+        { "belt_slice_rotation_angle", -30 },
+        { "gcode_remap_x",             "rev_x" },
+        { "gcode_remap_y",             "pos_z" },
+        { "gcode_remap_z",             "pos_y" },
+        { "belt_frame_tilt_decouple",  1 },
+        { "belt_frame_tilt_angle",     35 },
+        { "printable_area",            "0x0,300x0,300x250,0x250" },
+        { "printable_height",          123 },
+    });
+    DynamicPrintConfig selected = DynamicPrintConfig::full_print_config();
+    selected.set_deserialize_strict({
+        { "belt_printer",              !file_is_belt },
+        { "belt_slice_rotation",       "x" },
+        { "belt_slice_rotation_angle", 45 },
+        { "gcode_remap_x",             "pos_x" },
+        { "gcode_remap_y",             "pos_y" },
+        { "gcode_remap_z",             "pos_z" },
+        { "belt_frame_tilt_decouple",  0 },
+        { "belt_frame_tilt_angle",     50 },
+        { "printable_area",            "0x0,180x0,180x180,0x180" },
+        { "printable_height",          200 },
+    });
+
+    ScopedTemporaryFile temp(".gcode");
+    {
+        std::ofstream os(temp.string());
+        REQUIRE(os.is_open());
+        // A full config block, as the loader rejects one with fewer than 80 values.
+        os << "; generated by OrcaSlicer\n" << body << "; CONFIG_BLOCK_START\n";
+        for (const std::string &key : file.keys())
+            os << "; " << key << " = " << file.opt_serialize(key) << '\n';
+        os << "; CONFIG_BLOCK_END\n";
+        REQUIRE(os.good());
+    }
+    GCodeProcessor processor;
+    REQUIRE_NOTHROW(processor.process_file(temp.string()));
+
+    Model model;
+    Print print;
+    print.apply(model, selected);
+    REQUIRE_NOTHROW(print.apply_config_for_render(processor.export_config_for_render()));
+
+    // The file's belt settings win either way, so a non-belt file turns a selected belt printer's view off.
+    for (const char *key : { "belt_printer", "belt_slice_rotation", "belt_slice_rotation_angle", "gcode_remap_x",
+                             "gcode_remap_y", "gcode_remap_z", "belt_frame_tilt_decouple", "belt_frame_tilt_angle" }) {
+        CAPTURE(key);
+        CHECK(print.config().opt_serialize(key) == file.opt_serialize(key));
+    }
+    // Only a belt file brings the bed it was sliced for.
+    const DynamicPrintConfig &bed_source = file_is_belt ? file : selected;
+    for (const char *key : { "printable_area", "printable_height" }) {
+        CAPTURE(key);
+        CHECK(print.config().opt_serialize(key) == bed_source.opt_serialize(key));
+    }
+}
+
 TEST_CASE("Non-belt start G-code moves keep the first-layer Z in the processor", "[GCodeProcessor]")
 {
     // The belt path (GCodeWriter tests: "start-gcode prepare-stage moves keep their real Z")