From a80d0b49f0c0a5cebf9bcbd08d42d396e9be3cd2 Mon Sep 17 00:00:00 2001
From: Hanif Koh <hanifkoh@outlook.com>
Date: Tue, 22 Sep 2026 18:17:16 +0800
Subject: [PATCH] Report Per-Object Slicing Errors in the CLI

G-code generation collects errors raised per object, such as an empty
first layer, into one SlicingErrors exception whose own message is just
"Errors". The CLI's generic handler printed that word and recorded the
generic slicing error text, so a headless caller had nothing to act on.

Let Print render the per-object messages with each object's name, and have
the CLI catch SlicingErrors ahead of the generic handler, print that text
and record it as the result's error string. The exit code is unchanged. A
unit test lifts a cube off the bed and checks the message names the object.
---
 src/OrcaSlicer.cpp             |  6 ++++++
 src/libslic3r/Print.cpp        | 19 +++++++++++++++++++
 src/libslic3r/Print.hpp        |  4 ++++
 tests/fff_print/test_print.cpp | 26 ++++++++++++++++++++++++++
 4 files changed, 55 insertions(+)

diff --git a/src/OrcaSlicer.cpp b/src/OrcaSlicer.cpp
index 0c9bd0b1ee..7f65ba0fb9 100644
--- a/src/OrcaSlicer.cpp
+++ b/src/OrcaSlicer.cpp
@@ -7015,6 +7015,12 @@ int CLI::run(int argc, char **argv)
                                     }
                                 }
                                 sliced_info.sliced_plates.push_back(sliced_plate_info);
+                            } catch (const Slic3r::SlicingErrors &exs) {
+                                const std::string message = print_fff ? print_fff->slicing_errors_message(exs) : std::string(exs.what());
+                                BOOST_LOG_TRIVIAL(error) << "found slicing or export error for partplate " << index+1 << ": " << message;
+                                boost::nowide::cerr << message << std::endl;
+                                record_exit_reson(outfile_dir, CLI_SLICING_ERROR, index+1, message, sliced_info);
+                                flush_and_exit(CLI_SLICING_ERROR);
                             } catch (const std::exception &ex) {
                                 BOOST_LOG_TRIVIAL(error) << "found slicing or export error for partplate "<<index+1 << std::endl;
                                 boost::nowide::cerr << ex.what() << std::endl;
diff --git a/src/libslic3r/Print.cpp b/src/libslic3r/Print.cpp
index 833b811535..c3a7910a8c 100644
--- a/src/libslic3r/Print.cpp
+++ b/src/libslic3r/Print.cpp
@@ -1704,6 +1704,25 @@ StringObjectException Print::check_multi_filament_valid(const Print& print)
 
 // Precondition: Print::validate() requires the Print::apply() to be called its invocation.
 //BBS: refine seq-print validation logic
+// The exception's own message is just "Errors"; the detail is in the per-object errors,
+// whose object id is the PrintObject's.
+std::string Print::slicing_errors_message(const SlicingErrors &errors) const
+{
+    std::string message;
+    for (const SlicingError &error : errors.errors_) {
+        std::string object_name;
+        for (const PrintObject *object : m_objects)
+            if (object->id().id == error.objectId()) {
+                object_name = object->model_object()->name;
+                break;
+            }
+        if (!message.empty())
+            message += "\n";
+        message += object_name.empty() ? std::string(error.what()) : object_name + ": " + error.what();
+    }
+    return message;
+}
+
 StringObjectException Print::validate(std::vector<StringObjectException> *warnings, Polygons* collison_polygons, std::vector<std::pair<Polygon, float>>* height_polygons) const
 {
     auto add_warning = [warnings](StringObjectException w) {
diff --git a/src/libslic3r/Print.hpp b/src/libslic3r/Print.hpp
index 9c1782e047..12be35ea3c 100644
--- a/src/libslic3r/Print.hpp
+++ b/src/libslic3r/Print.hpp
@@ -30,6 +30,8 @@
 
 namespace Slic3r {
 
+class SlicingErrors;
+
 class GCode;
 class Layer;
 class ModelObject;
@@ -967,6 +969,8 @@ public:
 
     // Returns an empty string if valid, otherwise returns an error message.
     StringObjectException validate(std::vector<StringObjectException> *warnings = nullptr, Polygons* collison_polygons = nullptr, std::vector<std::pair<Polygon, float>>* height_polygons = nullptr) const override;
+    // The per-object messages of a SlicingErrors, each prefixed with its object's name.
+    std::string slicing_errors_message(const SlicingErrors &errors) const;
     double              skirt_first_layer_height() const;
     Flow                brim_flow() const;
     Flow                skirt_flow() const;
diff --git a/tests/fff_print/test_print.cpp b/tests/fff_print/test_print.cpp
index d7cd965343..383a7165d5 100644
--- a/tests/fff_print/test_print.cpp
+++ b/tests/fff_print/test_print.cpp
@@ -505,3 +505,29 @@ TEST_CASE("Sequential printing publishes the nozzle group result", "[Print][Mult
         CHECK(gcode.find("; SEQ-ND-OK") != std::string::npos);
     }
 }
+
+TEST_CASE("Slicing errors are reported per object with the object's name", "[Print]")
+{
+    Print print;
+    Model model;
+    init_print({Slic3r::Test::cube(20.)}, print, model);
+    // Lift the cube off the bed: its first layer is empty, which G-code export reports per object.
+    ModelObject *object = model.objects.front();
+    object->name = "floating cube";
+    object->instances.front()->set_offset(object->instances.front()->get_offset() + Vec3d(0., 0., 2.));
+    print.apply(model, DynamicPrintConfig::full_print_config());
+    print.set_status_silent();
+
+    ScopedTemporaryFile temp(".gcode");
+    std::string message;
+    try {
+        print.process();
+        print.export_gcode(temp.string(), nullptr, nullptr);
+        FAIL("slicing did not report the empty first layer");
+    } catch (const SlicingErrors &errors) {
+        REQUIRE(errors.errors_.size() == 1);
+        message = print.slicing_errors_message(errors);
+    }
+    CHECK(message.rfind("floating cube: ", 0) == 0);
+    CHECK(message.find("empty first layer") != std::string::npos);
+}