Fix some issues with Font property

Prevent out-of-bounds access
Make sure list is initialized in symbol editor frame
Don't re-init the list more frequently than necessary

Fixes https://gitlab.com/kicad/code/kicad/-/issues/16399

common/eda_text.cpp

@@ -857,7 +857,10 @@ void EDA_TEXT::SetFontIndex( int aIdx )
         std::vector<std::string> fontNames;
         Fontconfig()->ListFonts( fontNames, std::string( Pgm().GetLanguageTag().utf8_str() ) );
 
-        SetFont( KIFONT::FONT::GetFont( fontNames[ aIdx ], IsBold(), IsItalic() ) );
+        if( aIdx >= 0 && aIdx < static_cast<int>( fontNames.size() ) )
+            SetFont( KIFONT::FONT::GetFont( fontNames[ aIdx ], IsBold(), IsItalic() ) );
+        else
+            SetFont( nullptr );
     }
 }
 

common/widgets/properties_panel.h

@@ -49,6 +49,11 @@ public:
 
     virtual void AfterCommit() {}
 
+    /**
+     * Parents will call this when the user changes the UI language
+     */
+    virtual void LanguageChanged() {}
+
     wxPropertyGrid* GetPropertyGrid()
     {
         return m_grid;

eeschema/sch_edit_frame.cpp

@@ -1912,6 +1912,8 @@ void SCH_EDIT_FRAME::ShowChangedLanguage()
     m_auimgr.Update();
     m_hierarchy->UpdateHierarchyTree();
 
+    m_propertiesPanel->LanguageChanged();
+
     // status bar
     UpdateMsgPanel();
 

eeschema/symbol_editor/symbol_edit_frame.cpp

@@ -1250,6 +1250,8 @@ void SYMBOL_EDIT_FRAME::ShowChangedLanguage()
 
     m_treePane->GetLibTree()->ShowChangedLanguage();
 
+    m_propertiesPanel->LanguageChanged();
+
     // status bar
     UpdateMsgPanel();
 

eeschema/widgets/sch_properties_panel.cpp

@@ -87,6 +87,8 @@ SCH_PROPERTIES_PANEL::SCH_PROPERTIES_PANEL( wxWindow* aParent, SCH_BASE_FRAME* a
     {
         m_colorEditorInstance = static_cast<PG_COLOR_EDITOR*>( it->second );
     }
+
+    updateFontList();
 }
 
 
@@ -102,10 +104,6 @@ void SCH_PROPERTIES_PANEL::UpdateData()
     EE_SELECTION_TOOL* selectionTool = m_frame->GetToolManager()->GetTool<EE_SELECTION_TOOL>();
     const SELECTION& selection = selectionTool->GetSelection();
 
-    // TODO perhaps it could be called less often? use PROPERTIES_TOOL and catch MODEL_RELOAD?
-    if( SCH_EDIT_FRAME* schFrame = dynamic_cast<SCH_EDIT_FRAME*>( m_frame ) )
-        updateLists( schFrame->Schematic() );
-
     // Will actually just be updatePropertyValues() if selection hasn't changed
     rebuildProperties( selection );
 }
@@ -209,7 +207,13 @@ void SCH_PROPERTIES_PANEL::valueChanged( wxPropertyGridEvent& aEvent )
 }
 
 
-void SCH_PROPERTIES_PANEL::updateLists( const SCHEMATIC& aSchematic )
+void SCH_PROPERTIES_PANEL::LanguageChanged()
+{
+    updateFontList();
+}
+
+
+void SCH_PROPERTIES_PANEL::updateFontList()
 {
     wxPGChoices fonts;
 

eeschema/widgets/sch_properties_panel.h

@@ -43,6 +43,8 @@ public:
 
     void AfterCommit() override;
 
+    void LanguageChanged() override;
+
 protected:
     wxPGProperty* createPGProperty( const PROPERTY_BASE* aProperty ) const override;
 
@@ -51,8 +53,8 @@ protected:
     void valueChanging( wxPropertyGridEvent& aEvent ) override;
     void valueChanged( wxPropertyGridEvent& aEvent ) override;
 
-    ///< Regenerates caches of list properties
-    void updateLists( const SCHEMATIC& aSchematic );
+    ///< Regenerates caches of font list property
+    void updateFontList();
 
     SCH_BASE_FRAME* m_frame;
     PROPERTY_MANAGER& m_propMgr;