Auto-fill new net global / local label names from connectivity

Currently, new global or local net labels are auto-filled with the
net name if the wire is driven by a global or local label. This
currently happens recursively within SCH_LINE. This fix moves this
to determining the driver from the connectivity graph, and removes
the determination from the SCH_LINE code where it does not belong.

(cherry picked from commit b01796cb84)

eeschema/sch_line.cpp

@@ -101,47 +101,6 @@ wxString SCH_LINE::GetFriendlyName() const
 }
 
 
-wxString SCH_LINE::GetNetname( const SCH_SHEET_PATH& aSheet )
-{
-    std::list<const SCH_LINE *> checkedLines;
-    checkedLines.push_back(this);
-    return FindWireSegmentNetNameRecursive( this, checkedLines, aSheet );
-}
-
-
-wxString SCH_LINE::FindWireSegmentNetNameRecursive( SCH_LINE *line,
-                                                    std::list<const SCH_LINE *> &checkedLines,
-                                                    const SCH_SHEET_PATH& aSheet ) const
-{
-    for ( auto connected : line->ConnectedItems( aSheet ) )
-    {
-        if( connected->Type() == SCH_LINE_T )
-        {
-            if( std::find(checkedLines.begin(), checkedLines.end(),
-                          connected ) == checkedLines.end() )
-            {
-                SCH_LINE* connectedLine = static_cast<SCH_LINE*>( connected );
-                checkedLines.push_back( connectedLine );
-
-                wxString netName = FindWireSegmentNetNameRecursive( connectedLine, checkedLines,
-                                                                    aSheet );
-
-                if( !netName.IsEmpty() )
-                    return netName;
-            }
-        }
-        else if( connected->Type() == SCH_LABEL_T
-                 || connected->Type() == SCH_GLOBAL_LABEL_T
-                 || connected->Type() == SCH_DIRECTIVE_LABEL_T)
-        {
-            return static_cast<SCH_TEXT*>( connected )->GetText();
-        }
-
-    }
-    return "";
-}
-
-
 EDA_ITEM* SCH_LINE::Clone() const
 {
     return new SCH_LINE( *this );

eeschema/sch_line.h

@@ -63,14 +63,6 @@ public:
 
     wxString GetFriendlyName() const override;
 
-    /**
-     * @brief This function travel though all the connected wire segments
-     * to look for connected labels.
-     * @param aSheet - the sheet where the current wire segment is located
-     * @return returns the name of the wire if connected labels found, otherwise empty string
-     */
-    wxString GetNetname(const SCH_SHEET_PATH &aSheet);
-
     bool IsType( const std::vector<KICAD_T>& aScanTypes ) const override
     {
         if( SCH_ITEM::IsType( aScanTypes ) )

eeschema/tools/sch_drawing_tools.cpp

@@ -1184,6 +1184,24 @@ SCH_LINE* SCH_DRAWING_TOOLS::findWire( const VECTOR2I& aPosition )
 }
 
 
+wxString SCH_DRAWING_TOOLS::findWireLabelDriverName( SCH_LINE* aWire )
+{
+    wxASSERT( aWire->IsWire() );
+
+    SCH_SHEET_PATH sheetPath = m_frame->GetCurrentSheet();
+
+    if( SCH_CONNECTION* wireConnection = aWire->Connection( &sheetPath ) )
+    {
+        SCH_ITEM* wireDriver = wireConnection->Driver();
+
+        if( wireDriver && wireDriver->IsType( { SCH_LABEL_T, SCH_GLOBAL_LABEL_T } ) )
+            return wireConnection->LocalName();
+    }
+
+    return wxEmptyString;
+}
+
+
 SCH_TEXT* SCH_DRAWING_TOOLS::createNewText( const VECTOR2I& aPosition, int aType )
 {
     SCHEMATIC*          schematic = getModel<SCHEMATIC>();
@@ -1203,7 +1221,7 @@ SCH_TEXT* SCH_DRAWING_TOOLS::createNewText( const VECTOR2I& aPosition, int aType
         textItem = labelItem;
 
         if( SCH_LINE* wire = findWire( aPosition ) )
-            netName = wire->GetNetname( m_frame->GetCurrentSheet() );
+            netName = findWireLabelDriverName( wire );
 
         break;
 
@@ -1231,7 +1249,7 @@ SCH_TEXT* SCH_DRAWING_TOOLS::createNewText( const VECTOR2I& aPosition, int aType
         textItem = labelItem;
 
         if( SCH_LINE* wire = findWire( aPosition ) )
-            netName = wire->GetNetname( m_frame->GetCurrentSheet() );
+            netName = findWireLabelDriverName( wire );
 
         break;
 

eeschema/tools/sch_drawing_tools.h

@@ -60,6 +60,9 @@ public:
 private:
     SCH_LINE* findWire( const VECTOR2I& aPosition );
 
+    ///< Gets the (global) label name driving this wire, if it is driven by a label
+    wxString findWireLabelDriverName( SCH_LINE* aWire );
+
     SCH_TEXT* createNewText( const VECTOR2I& aPosition, int aType );
 
     SCH_HIERLABEL* importHierLabel( SCH_SHEET* aSheet );