Promote locally-labeled nets to global when tied to global buses

Fixes: lp:1822964
* https://bugs.launchpad.net/kicad/+bug/1822964

eeschema/connection_graph.cpp

@@ -538,17 +538,12 @@ void CONNECTION_GRAPH::buildConnectionGraph()
                 if( connection->IsDriver() )
                     subgraph->m_drivers.push_back( item );
 
-                if( item->Type() == SCH_NO_CONNECT_T )
+                connection->SetSubgraphCode( subgraph->m_code );
-                {
+
-                    subgraph->m_no_connect = item;
+                if( item->Type() == SCH_PIN_T )
-                }
-                else if( item->Type() == SCH_PIN_T )
                 {
                     auto pin = static_cast<SCH_PIN*>( item );
 
-                    if( pin->GetType() == PIN_NC )
-                        subgraph->m_no_connect = item;
-
                     // Invisible power pins need to be post-processed later
 
                     if( pin->IsPowerConnection() && !pin->IsVisible() )
@@ -557,8 +552,6 @@ void CONNECTION_GRAPH::buildConnectionGraph()
                     }
                 }
 
-                connection->SetSubgraphCode( subgraph->m_code );
-
                 std::list<SCH_ITEM*> members( item->ConnectedItems().begin(),
                                               item->ConnectedItems().end() );
 
@@ -633,6 +626,34 @@ void CONNECTION_GRAPH::buildConnectionGraph()
                 if( !subgraph->m_dirty )
                     continue;
 
+                // Special processing for some items
+                for( auto item : subgraph->m_items )
+                {
+                    switch( item->Type() )
+                    {
+                    case SCH_NO_CONNECT_T:
+                        subgraph->m_no_connect = item;
+                        break;
+
+                    case SCH_BUS_WIRE_ENTRY_T:
+                        subgraph->m_bus_entry = item;
+                        break;
+
+                    case SCH_PIN_T:
+                    {
+                        auto pin = static_cast<SCH_PIN*>( item );
+
+                        if( pin->GetType() == PIN_NC )
+                            subgraph->m_no_connect = item;
+
+                        break;
+                    }
+
+                    default:
+                        break;
+                    }
+                }
+
                 if( !subgraph->ResolveDrivers() )
                 {
                     subgraph->m_dirty = false;
@@ -1041,6 +1062,58 @@ void CONNECTION_GRAPH::buildConnectionGraph()
             }
         }
 
+        // Promote local nets connected to a globally-labeled bus to global
+
+        if( subgraph->m_bus_entry && connection->IsNet() )
+        {
+            auto be = static_cast<SCH_BUS_WIRE_ENTRY*>( subgraph->m_bus_entry );
+
+            if( be->m_connected_bus_item )
+            {
+                auto bus_conn = be->m_connected_bus_item->Connection( sheet );
+
+                if( bus_conn->Driver() &&
+                    bus_conn->Driver()->Type() == SCH_GLOBAL_LABEL_T )
+                {
+                    wxLogTrace( "CONN", "Net %s connected to global bus %s",
+                                connection->Name(), bus_conn->Name() );
+
+                    std::shared_ptr<SCH_CONNECTION> parent;
+
+                    for( auto member : bus_conn->Members() )
+                    {
+                        if( member->IsNet() &&
+                            member->Name( true ) == connection->Name( true ) )
+                        {
+                            if( member->NetCode() == 0 )
+                                assignNewNetCode( *member );
+
+                            parent = member;
+                        }
+                    }
+
+                    if( parent && ( parent->Name() != connection->Name() ) )
+                    {
+                        wxLogTrace( "CONN", "Promoting %s to %s", connection->Name(),
+                                    parent->Name() );
+
+                        connection->Clone( *parent );
+
+                        for( auto item : subgraph->m_items )
+                        {
+                            auto item_conn = item->Connection( sheet );
+                            item_conn->Clone( *connection );
+                        }
+                    }
+                    else
+                    {
+                        wxLogTrace( "CONN", "Could not find matching parent for %s!",
+                                    connection->Name() );
+                    }
+                }
+            }
+        }
+
         /**
          * Is this bus in the highest level of hierarchy? That is, does it
          * contain no hierarchical ports to parent sheets?  If so, we process it

eeschema/connection_graph.h

@@ -62,8 +62,8 @@ class CONNECTION_SUBGRAPH
 public:
     CONNECTION_SUBGRAPH( SCH_EDIT_FRAME* aFrame ) :
         m_dirty( false ), m_code( -1 ), m_multiple_power_ports( false ),
-        m_strong_driver( false ), m_no_connect( nullptr ), m_driver( nullptr ),
+        m_strong_driver( false ), m_no_connect( nullptr ), m_bus_entry( nullptr ),
-        m_frame( aFrame ), m_driver_connection( nullptr )
+        m_driver( nullptr ), m_frame( aFrame ), m_driver_connection( nullptr )
     {}
     /**
      * Determines which potential driver should drive the subgraph.
@@ -97,6 +97,9 @@ public:
     /// No-connect item in graph, if any
     SCH_ITEM* m_no_connect;
 
+    /// Bus entry in graph, if any
+    SCH_ITEM* m_bus_entry;
+
     std::vector<SCH_ITEM*> m_items;
 
     std::vector<SCH_ITEM*> m_drivers;