From 6b70f604607caa7ef986720b795558faaba0badb Mon Sep 17 00:00:00 2001
From: bubnikv <bubnikv@gmail.com>
Date: Thu, 10 Jan 2019 18:08:38 +0100
Subject: [PATCH] Fix of SPE-753 Slicer crash when SLA printer is selected and
 printer profile is changed

First, there was a bug in the preset Tabs, where a "printer_technology"
was incorrectly queried on "print" and "filament"
(or "sla_print" and "sla_material") profiles.

Second, there was an unsafe "printer_technology" getter, which would add
the missing key to the config container when queried for.
---
 src/slic3r/GUI/Preset.hpp       | 14 +++++++++++---
 src/slic3r/GUI/PresetBundle.cpp |  2 +-
 src/slic3r/GUI/Tab.cpp          | 14 ++++++++------
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/src/slic3r/GUI/Preset.hpp b/src/slic3r/GUI/Preset.hpp
index 24112cf10..021fea22c 100644
--- a/src/slic3r/GUI/Preset.hpp
+++ b/src/slic3r/GUI/Preset.hpp
@@ -161,9 +161,17 @@ public:
     }
     const std::string&  compatible_printers_condition() const { return const_cast<Preset*>(this)->compatible_printers_condition(); }
 
-    static PrinterTechnology& printer_technology(DynamicPrintConfig &cfg) { return cfg.option<ConfigOptionEnum<PrinterTechnology>>("printer_technology", true)->value; }
-    PrinterTechnology&        printer_technology() { return Preset::printer_technology(this->config); }
-    const PrinterTechnology&  printer_technology() const { return Preset::printer_technology(const_cast<Preset*>(this)->config); }
+    // Return a printer technology, return ptFFF if the printer technology is not set.
+    static PrinterTechnology printer_technology(const DynamicPrintConfig &cfg) {
+        auto *opt = cfg.option<ConfigOptionEnum<PrinterTechnology>>("printer_technology");
+        // The following assert may trigger when importing some legacy profile, 
+        // but it is safer to keep it here to capture the cases where the "printer_technology" key is queried, where it should not.
+        assert(opt != nullptr);
+        return (opt == nullptr) ? ptFFF : opt->value;
+    }
+    PrinterTechnology   printer_technology() const { return Preset::printer_technology(this->config); }
+    // This call returns a reference, it may add a new entry into the DynamicPrintConfig.
+    PrinterTechnology&  printer_technology_ref() { return this->config.option<ConfigOptionEnum<PrinterTechnology>>("printer_technology", true)->value; }
 
     // Mark this preset as compatible if it is compatible with active_printer.
     bool                update_compatible(const Preset &active_printer, const DynamicPrintConfig *extra_config, const Preset *active_print = nullptr);
diff --git a/src/slic3r/GUI/PresetBundle.cpp b/src/slic3r/GUI/PresetBundle.cpp
index 0021ce307..4c6c52763 100644
--- a/src/slic3r/GUI/PresetBundle.cpp
+++ b/src/slic3r/GUI/PresetBundle.cpp
@@ -81,7 +81,7 @@ PresetBundle::PresetBundle() :
     this->sla_prints.default_preset().inherits();
 
     this->printers.add_default_preset(Preset::sla_printer_options(), static_cast<const SLAMaterialConfig&>(SLAFullPrintConfig::defaults()), "- default SLA -");
-    this->printers.preset(1).printer_technology() = ptSLA;
+    this->printers.preset(1).printer_technology_ref() = ptSLA;
     for (size_t i = 0; i < 2; ++ i) {
 		// The following ugly switch is to avoid printers.preset(0) to return the edited instance, as the 0th default is the current one.
 		Preset &preset = this->printers.default_preset(i);
diff --git a/src/slic3r/GUI/Tab.cpp b/src/slic3r/GUI/Tab.cpp
index 53ead470e..4daaf5d63 100644
--- a/src/slic3r/GUI/Tab.cpp
+++ b/src/slic3r/GUI/Tab.cpp
@@ -2296,11 +2296,13 @@ void Tab::load_current_preset()
 	(preset.is_default || preset.is_system) ? m_btn_delete_preset->Disable() : m_btn_delete_preset->Enable(true);
 
     update();
-    // For the printer profile, generate the extruder pages.
-    if (preset.printer_technology() == ptFFF)
-        on_preset_loaded();
-    else
-        wxGetApp().sidebar().update_objects_list_extruder_column(1);
+	if (m_name == "printer") {
+		// For the printer profile, generate the extruder pages.
+		if (preset.printer_technology() == ptFFF)
+			on_preset_loaded();
+		else
+			wxGetApp().sidebar().update_objects_list_extruder_column(1);
+	}
     // Reload preset pages with the new configuration values.
     reload_config();
 
@@ -2325,7 +2327,7 @@ void Tab::load_current_preset()
 
         // update show/hide tabs
         if (m_name == "printer") {
-            PrinterTechnology& printer_technology = m_presets->get_edited_preset().printer_technology();
+            const PrinterTechnology printer_technology = m_presets->get_edited_preset().printer_technology();
             if (printer_technology != static_cast<TabPrinter*>(this)->m_printer_technology)
             {
                 for (auto tab : wxGetApp().tabs_list) {