Fix a few more symbol library inheritance bugs.

Replace some C casts with C++ dynamic_cast.

Fix iterator bug when deleting inherited symbols from legacy file format
symbol library cache.

Remove unnecessary const when return wxString object instead of reference.

eeschema/class_libentry.cpp

@@ -112,7 +112,7 @@ LIB_PART::LIB_PART( const wxString& aName, LIB_PART* aParent, PART_LIB* aLibrary
 }
 
 
-LIB_PART::LIB_PART( LIB_PART& aPart, PART_LIB* aLibrary ) :
+LIB_PART::LIB_PART( const LIB_PART& aPart, PART_LIB* aLibrary ) :
     EDA_ITEM( aPart ),
     m_me( this, null_deleter() )
 {
@@ -134,7 +134,7 @@ LIB_PART::LIB_PART( LIB_PART& aPart, PART_LIB* aLibrary ) :
     m_keyWords            = aPart.m_keyWords;
     m_docFileName         = aPart.m_docFileName;
 
-    for( LIB_ITEM& oldItem : aPart.m_drawings )
+    for( const LIB_ITEM& oldItem : aPart.m_drawings )
     {
         if( ( oldItem.GetFlags() & ( IS_NEW | STRUCT_DELETED ) ) != 0 )
             continue;
@@ -278,7 +278,7 @@ std::unique_ptr< LIB_PART > LIB_PART::Flatten() const
                      wxString::Format( "Parent of derived symbol '%s' undefined", m_name ) );
 
         // Copy the parent.
-        retv.reset( new LIB_PART( *const_cast< LIB_PART* >( parent.get() ) ) );
+        retv.reset( new LIB_PART( *parent.get() ) );
 
         // Now add the inherited part (this) information.
         retv->SetName( m_name );
@@ -291,7 +291,7 @@ std::unique_ptr< LIB_PART > LIB_PART::Flatten() const
     }
     else
     {
-        retv.reset( new LIB_PART( *const_cast< LIB_PART* >( this ) ) );
+        retv.reset( new LIB_PART( *this ) );
     }
 
     return retv;

eeschema/class_libentry.h

@@ -129,7 +129,7 @@ public:
     /**
      * Copy constructor.
      */
-    LIB_PART( LIB_PART& aPart, PART_LIB* aLibrary = NULL );
+    LIB_PART( const LIB_PART& aPart, PART_LIB* aLibrary = NULL );
 
     virtual ~LIB_PART();
 
@@ -144,7 +144,7 @@ public:
     }
 
     virtual void SetName( const wxString& aName );
-    const wxString GetName() const override { return m_name; }
+    wxString GetName() const override { return m_name; }
 
     LIB_ID GetLibId() const override { return m_libId; }
     void SetLibId( const LIB_ID& aLibId ) { m_libId = aLibId; }
@@ -156,21 +156,21 @@ public:
         m_description = aDescription;
     }
 
-    const wxString GetDescription() override { return m_description; }
+    wxString GetDescription() override { return m_description; }
 
     void SetKeyWords( const wxString& aKeyWords )
     {
         m_keyWords = aKeyWords;
     }
 
-    const wxString GetKeyWords() const { return m_keyWords; }
+    wxString GetKeyWords() const { return m_keyWords; }
 
     void SetDocFileName( const wxString& aDocFileName )
     {
         m_docFileName = aDocFileName;
     }
 
-    const wxString GetDocFileName() const { return m_docFileName; }
+    wxString GetDocFileName() const { return m_docFileName; }
 
     wxString GetSearchText() override;
 

eeschema/sch_legacy_plugin.cpp

@@ -4183,12 +4183,12 @@ void SCH_LEGACY_PLUGIN_CACHE::DeleteSymbol( const wxString& aSymbolName )
         {
             if( it1->second->IsAlias() && it1->second->GetParent().lock() == rootPart->SharedPtr() )
             {
-                delete it->second;
-                it = m_symbols.erase( it );
+                delete it1->second;
+                it1 = m_symbols.erase( it1 );
             }
             else
             {
-                it++;
+                it1++;
             }
         }
 

eeschema/sch_view.cpp

@@ -141,7 +141,7 @@ void SCH_VIEW::DisplayComponent( LIB_PART* aPart )
         if( item.Type() != LIB_FIELD_T )
             continue;
 
-        LIB_FIELD* field = (LIB_FIELD*) &item;
+        LIB_FIELD* field = dynamic_cast< LIB_FIELD* >( &item );
 
         if( field->GetId() < MANDATORY_FIELDS )
             Add( &item );
@@ -162,7 +162,7 @@ void SCH_VIEW::DisplayComponent( LIB_PART* aPart )
         // The mandatory fields are already in place so we only add user defined fields.
         if( item.Type() == LIB_FIELD_T )
         {
-            LIB_FIELD* field = (LIB_FIELD*) &item;
+            LIB_FIELD* field = dynamic_cast< LIB_FIELD* >( &item );
 
             if( field->GetId() < MANDATORY_FIELDS )
                 continue;

include/footprint_info.h

@@ -81,7 +81,7 @@ public:
         return m_nickname;
     }
 
-    const wxString GetName() const override
+    wxString GetName() const override
     {
         return m_fpname;
     }
@@ -91,13 +91,13 @@ public:
         return LIB_ID( m_nickname, m_fpname );
     }
 
-    const wxString GetDescription() override
+    wxString GetDescription() override
     {
         ensure_loaded();
         return m_doc;
     }
 
-    const wxString GetKeywords()
+    wxString GetKeywords()
     {
         ensure_loaded();
         return m_keywords;

include/lib_tree_item.h

@@ -41,10 +41,10 @@ class APIEXPORT LIB_TREE_ITEM
 public:
     virtual LIB_ID GetLibId() const = 0;
 
-    virtual const wxString GetName() const = 0;
+    virtual wxString GetName() const = 0;
     virtual wxString GetLibNickname() const = 0;
 
-    virtual const wxString GetDescription() = 0;
+    virtual wxString GetDescription() = 0;
 
     virtual wxString GetSearchText() { return wxEmptyString; }