Keep track of which nets are currently in use.

Fixes: lp:1798006
* https://bugs.launchpad.net/kicad/+bug/1798006

common/widgets/net_selector.cpp

@@ -236,14 +236,15 @@ protected:
 
         for( NETINFO_ITEM* netinfo : *m_netinfoList )
         {
-            if( netinfo->GetNet() == 0 )
-                continue;  // we'll insert NO_NET after sorting
-
-            if( filter.IsEmpty() || wxString( netinfo->GetNetname() ).MakeLower().Matches( filter ) )
-                netNames.push_back( netinfo->GetNetname() );
+            if( netinfo->GetNet() > 0 && netinfo->IsCurrent() )
+            {
+                if( filter.IsEmpty() || wxString( netinfo->GetNetname() ).MakeLower().Matches( filter ) )
+                    netNames.push_back( netinfo->GetNetname() );
+            }
         }
         std::sort( netNames.begin(), netNames.end() );
 
+        // Special handling for <no net>
         if( filter.IsEmpty() || wxString( NO_NET ).MakeLower().Matches( filter ) )
             netNames.insert( netNames.begin(), NO_NET );
 

pcbnew/board_netlist_updater.cpp

@@ -306,10 +306,14 @@ bool BOARD_NETLIST_UPDATER::updateComponentPadConnections( MODULE* aPcbComponent
         }
         else                                 // New footprint pad has a net.
         {
-            if( net.GetNetName() != pad->GetNetname() )
+            const wxString& netName = net.GetNetName();
+            NETINFO_ITEM* netinfo = m_board->FindNet( netName );
+
+            if( netinfo && !m_isDryRun )
+                netinfo->SetIsCurrent( true );
+
+            if( pad->GetNetname() != netName )
             {
-                const wxString& netName = net.GetNetName();
-                NETINFO_ITEM* netinfo = m_board->FindNet( netName );
 
                 if( netinfo == nullptr )
                 {
@@ -326,9 +330,9 @@ bool BOARD_NETLIST_UPDATER::updateComponentPadConnections( MODULE* aPcbComponent
                         changed = true;
                         netinfo = new NETINFO_ITEM( m_board, netName );
                         m_commit.Add( netinfo );
-                        m_addedNets[netName] = netinfo;
                     }
 
+                    m_addedNets[netName] = netinfo;
                     msg.Printf( _( "Add net %s." ), netName );
                     m_reporter->Report( msg, REPORTER::RPT_ACTION );
                 }
@@ -626,6 +630,11 @@ bool BOARD_NETLIST_UPDATER::UpdateNetlist( NETLIST& aNetlist )
     if( !m_isDryRun )
     {
         m_board->SetStatus( 0 );
+
+        // Mark all nets (except <no net>) as stale; we'll update those to current that
+        // we find in the netlist
+        for( NETINFO_ITEM* net : m_board->GetNetInfo() )
+            net->SetIsCurrent( net->GetNet() == 0 );
     }
 
     for( unsigned i = 0; i < aNetlist.GetCount(); i++ )

pcbnew/class_board.cpp

@@ -2484,19 +2484,23 @@ void BOARD::updateComponentPadConnections( NETLIST& aNetlist, MODULE* footprint,
         }
         else                                 // Footprint pad has a net.
         {
-            if( net.GetNetName() != pad->GetNetname() )
+            const wxString& netName = net.GetNetName();
+            NETINFO_ITEM* netinfo = FindNet( netName );
+
+            if( netinfo && !aNetlist.IsDryRun() )
+                netinfo->SetIsCurrent( true );
+
+            if( pad->GetNetname() != netName )
             {
                 msg.Printf( _( "Changing footprint %s pad %s net from %s to %s." ),
                             footprint->GetReference(),
                             pad->GetName(),
                             pad->GetNetname(),
-                            net.GetNetName() );
+                            netName );
                 aReporter.Report( msg, REPORTER::RPT_ACTION );
 
                 if( !aNetlist.IsDryRun() )
                 {
-                    NETINFO_ITEM* netinfo = FindNet( net.GetNetName() );
-
                     if( netinfo == NULL )
                     {
                         // It is a new net, we have to add it
@@ -2556,6 +2560,11 @@ void BOARD::ReplaceNetlist( NETLIST& aNetlist, bool aDeleteSinglePadNets,
 
     m_Status_Pcb = 0;
 
+    // Mark all nets (except <no net>) as stale; we'll update those to current that
+    // we find in the netlist
+    for( NETINFO_ITEM* net : m_NetInfo )
+        net->SetIsCurrent( net->GetNet() == 0 );
+
     for( i = 0;  i < aNetlist.GetCount();  i++ )
     {
         COMPONENT* component = aNetlist.GetComponent( i );

pcbnew/dialogs/panel_setup_netclasses.cpp

@@ -146,30 +146,16 @@ bool PANEL_SETUP_NETCLASSES::TransferDataToWindow()
     for( NETCLASSES::iterator i = netclasses.begin();  i != netclasses.end();  ++i, ++row )
         netclassToGridRow( m_Frame->GetUserUnits(), m_netclassGrid, row, i->second );
 
-    // Reassure that all nets have net classes assigned
+    // ensure that all nets have net classes assigned
     m_Pcb->BuildListOfNets();
 
     if( m_membershipGrid->GetNumberRows() )
         m_membershipGrid->DeleteRows( 0, m_membershipGrid->GetNumberRows() );
 
-    // Initialize list of nets for Default Net Class
-    for( NETCLASS::iterator name = netclass->begin();  name != netclass->end();  ++name )
+    for( NETINFO_ITEM* net : m_Pcb->GetNetInfo() )
     {
-        if( name->IsEmpty() )
-            // @TODO go fix m_Pcb->SynchronizeNetsAndNetClasses() so that the netcode==0
-            //       is not present in the BOARD::m_NetClasses
-            continue;
-        else
-            addNet( *name, netclass->GetName() );
-    }
-
-    // Initialize list of nets for others (custom) Net Classes
-    for( NETCLASSES::const_iterator nc = netclasses.begin();  nc != netclasses.end();  ++nc )
-    {
-        netclass = nc->second;
-
-        for( NETCLASS::const_iterator name = netclass->begin();  name != netclass->end();  ++name )
-            addNet( *name, netclass->GetName() );
+        if( net->GetNet() > 0 && net->IsCurrent() )
+            addNet( net->GetNetname(), net->GetNetClass()->GetName() );
     }
 
     return true;

pcbnew/netinfo.h

@@ -74,6 +74,10 @@ private:
     int m_NetCode;              ///< A number equivalent to the net name.
                                 ///< Used for fast comparisons in ratsnest and DRC computations.
 
+    bool m_isCurrent;           ///< Indicates the net is currently in use.  We still store those
+                                ///< that are not during a session for undo/redo and to keep
+                                ///< netclass membership information.
+
     wxString m_Netname;         ///< Full net name like /mysheet/mysubsheet/vout used by Eeschema
 
     wxString m_ShortNetname;    ///< short net name, like vout from /mysheet/mysubsheet/vout
@@ -240,6 +244,10 @@ public:
      */
     const wxString& GetShortNetname() const { return m_ShortNetname; }
 
+    bool IsCurrent() const { return m_isCurrent; }
+
+    void SetIsCurrent( bool isCurrent ) { m_isCurrent = isCurrent; }
+
     /**
      * Function GetMsgPanelInfo
      * returns the information about the #NETINFO_ITEM in \a aList to display in the

pcbnew/netinfo_item.cpp

@@ -50,7 +50,10 @@
 
 NETINFO_ITEM::NETINFO_ITEM( BOARD* aParent, const wxString& aNetName, int aNetCode ) :
     BOARD_ITEM( aParent, PCB_NETINFO_T ),
-    m_NetCode( aNetCode ), m_Netname( aNetName ), m_ShortNetname( m_Netname.AfterLast( '/' ) )
+    m_NetCode( aNetCode ),
+    m_isCurrent( true ),
+    m_Netname( aNetName ),
+    m_ShortNetname( m_Netname.AfterLast( '/' ) )
 {
     m_parent = aParent;