symbol editor: Improve pin duplication

When duplicating pins in the symbol editor the duplicated pins will have
unique pin numbers assigned if the duplication target had the pin number
specified

eeschema/lib_symbol.cpp

@@ -1153,6 +1153,27 @@ bool LIB_SYMBOL::HasConversion() const
     return false;
 }
 
+int LIB_SYMBOL::GetMaxPinNumber() const
+{
+    int                        maxPinNumber = 0;
+    LIB_SYMBOL_SPTR            parent = m_parent.lock();
+    const LIB_ITEMS_CONTAINER& drawItems = parent ? parent->m_drawings : m_drawings;
+
+    for( const LIB_ITEM& item : drawItems[LIB_PIN_T] )
+    {
+        const LIB_PIN* pin = static_cast<const LIB_PIN*>( &item );
+        long           currentPinNumber = 0;
+        bool           isNum = pin->GetNumber().ToLong( &currentPinNumber );
+
+        if( isNum && currentPinNumber > maxPinNumber )
+        {
+            maxPinNumber = currentPinNumber;
+        }
+    }
+
+    return maxPinNumber;
+}
+
 
 void LIB_SYMBOL::ClearTempFlags()
 {

eeschema/lib_symbol.h

@@ -453,6 +453,12 @@ public:
      */
     bool HasConversion() const;
 
+    /**
+     * @return the highest pin number of the symbol's pins.
+     * If none of the pins has pin number assigned it returns 0.
+     */
+    int GetMaxPinNumber() const;
+
     /**
      * Clears the status flag all draw objects in this symbol.
      */

eeschema/tools/symbol_editor_edit_tool.cpp

@@ -605,6 +605,17 @@ void SYMBOL_EDITOR_EDIT_TOOL::editSymbolProperties()
     }
 }
 
+void SYMBOL_EDITOR_EDIT_TOOL::handlePinDuplication( LIB_PIN* aOldPin, LIB_PIN* aNewPin,
+                                                    int& aSymbolLastPinNumber )
+{
+    if( !aNewPin->GetNumber().IsEmpty() )
+    {
+        // when duplicating a pin in symbol editor, assigning identical pin number
+        // to the old one does not makes any sense, so assign the next unassigned number to it
+        aSymbolLastPinNumber++;
+        aNewPin->SetNumber( wxString::Format( wxT( "%i" ), aSymbolLastPinNumber ) );
+    }
+}
 
 int SYMBOL_EDITOR_EDIT_TOOL::PinTable( const TOOL_EVENT& aEvent )
 {
@@ -803,11 +814,24 @@ int SYMBOL_EDITOR_EDIT_TOOL::Duplicate( const TOOL_EVENT& aEvent )
         saveCopyInUndoList( m_frame->GetCurSymbol(), UNDO_REDO::LIBEDIT );
 
     EDA_ITEMS newItems;
+    int       symbolLastPinNumber = -1;
 
     for( unsigned ii = 0; ii < selection.GetSize(); ++ii )
     {
         LIB_ITEM* oldItem = static_cast<LIB_ITEM*>( selection.GetItem( ii ) );
         LIB_ITEM* newItem = (LIB_ITEM*) oldItem->Clone();
+
+        if( oldItem->Type() == LIB_PIN_T )
+        {
+            if( symbolLastPinNumber == -1 )
+            {
+                symbolLastPinNumber = symbol->GetMaxPinNumber();
+            }
+
+            handlePinDuplication( static_cast<LIB_PIN*>( oldItem ),
+                                  static_cast<LIB_PIN*>( newItem ), symbolLastPinNumber );
+        }
+
         oldItem->ClearFlags( IS_NEW | IS_PASTED | SELECTED );
         newItem->SetFlags( IS_NEW | IS_PASTED | SELECTED );
         newItem->SetParent( symbol );

eeschema/tools/symbol_editor_edit_tool.h

@@ -69,6 +69,7 @@ private:
     void editTextBoxProperties( LIB_ITEM* aItem );
     void editFieldProperties( LIB_FIELD* aField );
     void editSymbolProperties();
+    void handlePinDuplication(LIB_PIN* aOldPin, LIB_PIN* aNewPin, int &aSymbolLastPinNumber );
 
     ///< Set up handlers for various events.
     void setTransitions() override;