Fixed a crash when deleting the last object with autocenter enabled (prusa3d/PrusaSlicer#11186).

(cherry picked from commit prusa3d/PrusaSlicer@926af1ab8d)

src/libslic3r/Model.cpp

@@ -2289,6 +2289,14 @@ int ModelObject::get_repaired_errors_count(const int vol_idx /*= -1*/) const
             stats.facets_reversed + stats.backwards_edges;
 }
 
+bool ModelObject::has_solid_mesh() const
+{
+    for (const ModelVolume* volume : volumes)
+        if (volume->is_model_part())
+            return true;
+    return false;
+}
+
 void ModelVolume::set_material_id(t_model_material_id material_id)
 {
     m_material_id = material_id;

src/libslic3r/Model.hpp

@@ -523,6 +523,8 @@ public:
     // Get count of errors in the mesh( or all object's meshes, if volume index isn't defined)
     int         get_repaired_errors_count(const int vol_idx = -1) const;
 
+    // Detect if object has at least one solid mash
+    bool has_solid_mesh() const;
     bool is_cut() const { return cut_id.id().valid(); }
     bool has_connectors() const;
 private:

src/slic3r/GUI/GUI_ObjectList.cpp

@@ -1,3 +1,9 @@
+///|/ Copyright (c) Prusa Research 2018 - 2023 Oleksandra Iushchenko @YuSanka, Enrico Turri @enricoturri1966, Lukáš Matěna @lukasmatena, Lukáš Hejl @hejllukas, Tomáš Mészáros @tamasmeszaros, Vojtěch Bubník @bubnikv, Pavel Mikuš @Godrak, David Kocík @kocikdav, Filip Sykala @Jony01, Vojtěch Král @vojtechkral
+///|/ Copyright (c) 2021 Mathias Rasmussen
+///|/ Copyright (c) 2020 rongith
+///|/
+///|/ PrusaSlicer is released under the terms of the AGPLv3 or higher
+///|/
 #include "libslic3r/libslic3r.h"
 #include "libslic3r/PresetBundle.hpp"
 #include "GUI_ObjectList.hpp"
@@ -3030,48 +3036,6 @@ bool ObjectList::can_split_instances()
     return selection.is_multiple_full_instance() || selection.is_single_full_instance();
 }
 
-bool ObjectList::can_merge_to_multipart_object() const
-{
-    if (has_selected_cut_object())
-        return false;
-
-    if (printer_technology() == ptSLA)
-        return false;
-
-    wxDataViewItemArray sels;
-    GetSelections(sels);
-    if (sels.IsEmpty())
-        return false;
-
-    // should be selected just objects
-    for (wxDataViewItem item : sels) {
-        if (!(m_objects_model->GetItemType(item) & (itObject | itInstance)))
-            return false;
-    }
-
-    return true;
-}
-
-bool ObjectList::can_merge_to_single_object() const
-{
-    int obj_idx = get_selected_obj_idx();
-    if (obj_idx < 0)
-        return false;
-
-    // selected object should be multipart
-    return (*m_objects)[obj_idx]->volumes.size() > 1;
-}
-
-bool ObjectList::can_mesh_boolean() const
-{
-    int obj_idx = get_selected_obj_idx();
-    if (obj_idx < 0)
-        return false;
-
-    // selected object should be multi mesh
-    return (*m_objects)[obj_idx]->volumes.size() > 1 || ((*m_objects)[obj_idx]->volumes.size() == 1 && (*m_objects)[obj_idx]->volumes[0]->is_splittable());
-}
-
 bool ObjectList::has_selected_cut_object() const
 {
     wxDataViewItemArray sels;
@@ -3081,7 +3045,9 @@ bool ObjectList::has_selected_cut_object() const
 
     for (wxDataViewItem item : sels) {
         const int obj_idx = m_objects_model->GetObjectIdByItem(item);
-        if (obj_idx >= 0 && object(obj_idx)->is_cut())
+        // ys_FIXME: The obj_idx<size condition is a workaround for https://github.com/prusa3d/PrusaSlicer/issues/11186,
+        // but not the correct fix. The deleted item probably should not be in sels in the first place.
+        if (obj_idx >= 0 && obj_idx < int(m_objects->size()) && object(obj_idx)->is_cut())
             return true;
     }
 
@@ -3101,9 +3067,10 @@ void ObjectList::invalidate_cut_info_for_selection()
 void ObjectList::invalidate_cut_info_for_object(int obj_idx)
 {
     ModelObject* init_obj = object(obj_idx);
-    if (!init_obj->is_cut()) return;
+    if (!init_obj->is_cut())
+        return;
 
-    take_snapshot("Invalidate cut info");
+    take_snapshot(_u8L("Invalidate cut info"));
 
     const CutObjectBase cut_id = init_obj->cut_id;
     // invalidate cut for related objects (which have the same cut_id)
@@ -3133,13 +3100,7 @@ void ObjectList::delete_all_connectors_for_object(int obj_idx)
     if (!init_obj->is_cut())
         return;
 
-    take_snapshot("Delete all connectors");
-
-    auto has_solid_mesh = [](ModelObject* obj) {
-        for (const ModelVolume *volume : obj->volumes)
-            if (volume->is_model_part()) return true;
-        return false;
-    };
+    take_snapshot(_u8L("Delete all connectors"));
 
     const CutObjectBase cut_id = init_obj->cut_id;
     // Delete all connectors for related objects (which have the same cut_id)
@@ -3148,7 +3109,7 @@ void ObjectList::delete_all_connectors_for_object(int obj_idx)
         if (ModelObject* obj = object(idx); obj->cut_id.is_equal(cut_id)) {
             obj->delete_connectors();
 
-            if (obj->volumes.empty() || !has_solid_mesh(obj)) {
+            if (obj->volumes.empty() || !obj->has_solid_mesh()) {
                 model.delete_object(idx);
                 m_objects_model->Delete(m_objects_model->GetItemById(idx));
                 continue;
@@ -3162,6 +3123,46 @@ void ObjectList::delete_all_connectors_for_object(int obj_idx)
     update_lock_icons_for_model();
 }
 
+bool ObjectList::can_merge_to_multipart_object() const
+{
+    if (has_selected_cut_object())
+        return false;
+
+    if (printer_technology() == ptSLA)
+        return false;
+
+    wxDataViewItemArray sels;
+    GetSelections(sels);
+    if (sels.IsEmpty())
+        return false;
+
+    // should be selected just objects
+    for (wxDataViewItem item : sels)
+        if (!(m_objects_model->GetItemType(item) & (itObject | itInstance)))
+            return false;
+
+    return true;
+}
+
+bool ObjectList::can_merge_to_single_object() const
+{
+    int obj_idx = get_selected_obj_idx();
+    if (obj_idx < 0)
+        return false;
+
+    // selected object should be multipart
+    return (*m_objects)[obj_idx]->volumes.size() > 1;
+}
+
+bool ObjectList::can_mesh_boolean() const
+{
+    int obj_idx = get_selected_obj_idx();
+    if (obj_idx < 0)
+        return false;
+
+    // selected object should be multi mesh
+    return (*m_objects)[obj_idx]->volumes.size() > 1 || ((*m_objects)[obj_idx]->volumes.size() == 1 && (*m_objects)[obj_idx]->volumes[0]->is_splittable());
+}
 
 // NO_PARAMETERS function call means that changed object index will be determine from Selection()
 void ObjectList::changed_object(const int obj_idx/* = -1*/) const