Fix connectivity to only resolve conflicts on netlist load

Fixes https://gitlab.com/kicad/code/kicad/-/issues/8007

pcbnew/board_commit.cpp

@@ -37,14 +37,16 @@
 using namespace std::placeholders;
 
 
-BOARD_COMMIT::BOARD_COMMIT( PCB_TOOL_BASE* aTool )
+BOARD_COMMIT::BOARD_COMMIT( PCB_TOOL_BASE* aTool ) :
+        m_resolveNetConflicts( false )
 {
     m_toolMgr = aTool->GetManager();
     m_isFootprintEditor = aTool->IsFootprintEditor();
 }
 
 
-BOARD_COMMIT::BOARD_COMMIT( EDA_DRAW_FRAME* aFrame )
+BOARD_COMMIT::BOARD_COMMIT( EDA_DRAW_FRAME* aFrame ) :
+        m_resolveNetConflicts( false )
 {
     m_toolMgr = aFrame->GetToolManager();
     m_isFootprintEditor = aFrame->IsType( FRAME_FOOTPRINT_EDITOR );
@@ -350,6 +352,9 @@ void BOARD_COMMIT::Push( const wxString& aMessage, bool aCreateUndoEntry, bool a
     {
         size_t num_changes = m_changes.size();
 
+        if( m_resolveNetConflicts )
+            connectivity->PropagateNets( this, PROPAGATE_MODE::RESOLVE_CONFLICTS );
+
         connectivity->RecalculateRatsnest( this );
         connectivity->ClearDynamicRatsnest();
         frame->GetCanvas()->RedrawRatsnest();

pcbnew/board_commit.h

@@ -51,12 +51,23 @@ public:
     COMMIT&      Stage(
                  const PICKED_ITEMS_LIST& aItems, UNDO_REDO aModFlag = UNDO_REDO::UNSPECIFIED ) override;
 
+    /**
+     * Sets a flag that will cause Push() to resolve net conflicts on track/via clusters instead
+     * of the default behavior which is to skip updating track/via clusters that have conflicts.
+     * This is used in the netlist updater to update any clusters that were changed due to pad nets
+     * changing, but should not be used for other changes as you typically don't want to change
+     * track/via nets due to temporary conflicts created by board editing operations.
+     * @param aResolve is true if this commit should resolve conflicting track/via net assignments
+    */
+    void SetResolveNetConflicts( bool aResolve = true ) { m_resolveNetConflicts = aResolve; }
+
 private:
     virtual EDA_ITEM* parentObject( EDA_ITEM* aItem ) const override;
 
 private:
     TOOL_MANAGER* m_toolMgr;
     bool          m_isFootprintEditor;
+    bool          m_resolveNetConflicts;
 };
 
 #endif

pcbnew/connectivity/connectivity_algo.cpp

@@ -477,11 +477,19 @@ void CN_CONNECTIVITY_ALGO::Build( const std::vector<BOARD_ITEM*>& aItems )
 }
 
 
-void CN_CONNECTIVITY_ALGO::propagateConnections( BOARD_COMMIT* aCommit )
+void CN_CONNECTIVITY_ALGO::propagateConnections( BOARD_COMMIT* aCommit, PROPAGATE_MODE aMode )
 {
+    bool skipConflicts = ( aMode == PROPAGATE_MODE::SKIP_CONFLICTS );
+
+    wxLogTrace( "CN", "propagateConnections: propagate skip conflicts? %d", skipConflicts );
+
     for( const auto& cluster : m_connClusters )
     {
-        if( cluster->IsOrphaned() )
+        if( skipConflicts && cluster->IsConflicting() )
+        {
+            wxLogTrace( "CN", "Conflicting nets in cluster %p; skipping update", cluster.get() );
+        }
+        else if( cluster->IsOrphaned() )
         {
             wxLogTrace( "CN", "Skipping orphaned cluster %p [net: %s]", cluster.get(),
                     (const char*) cluster->OriginNetName().c_str() );
@@ -531,10 +539,10 @@ void CN_CONNECTIVITY_ALGO::propagateConnections( BOARD_COMMIT* aCommit )
 }
 
 
-void CN_CONNECTIVITY_ALGO::PropagateNets( BOARD_COMMIT* aCommit )
+void CN_CONNECTIVITY_ALGO::PropagateNets( BOARD_COMMIT* aCommit, PROPAGATE_MODE aMode )
 {
     m_connClusters = SearchClusters( CSM_PROPAGATE );
-    propagateConnections( aCommit );
+    propagateConnections( aCommit, aMode );
 }
 
 

pcbnew/connectivity/connectivity_algo.h

@@ -168,7 +168,8 @@ private:
 
     void    searchConnections();
 
-    void    propagateConnections( BOARD_COMMIT* aCommit = nullptr );
+    void    propagateConnections( BOARD_COMMIT* aCommit = nullptr,
+                                  PROPAGATE_MODE aMode = PROPAGATE_MODE::SKIP_CONFLICTS );
 
     template <class Container, class BItem>
     void add( Container& c, BItem brditem )
@@ -239,8 +240,10 @@ public:
     /**
      * Propagates nets from pads to other items in clusters
      * @param aCommit is used to store undo information for items modified by the call
+     * @param aMode controls how clusters with conflicting nets are resolved
      */
-    void PropagateNets( BOARD_COMMIT* aCommit = nullptr );
+    void PropagateNets( BOARD_COMMIT* aCommit = nullptr,
+                        PROPAGATE_MODE aMode = PROPAGATE_MODE::SKIP_CONFLICTS );
 
     void FindIsolatedCopperIslands( ZONE* aZone, PCB_LAYER_ID aLayer, std::vector<int>& aIslands );
 

pcbnew/connectivity/connectivity_data.cpp

@@ -339,11 +339,12 @@ void CONNECTIVITY_DATA::HideDynamicRatsnest()
 }
 
 
-void CONNECTIVITY_DATA::PropagateNets()
+void CONNECTIVITY_DATA::PropagateNets( BOARD_COMMIT* aCommit, PROPAGATE_MODE aMode )
 {
-    m_connAlgo->PropagateNets();
+    m_connAlgo->PropagateNets( aCommit, aMode );
 }
 
+
 bool CONNECTIVITY_DATA::IsConnectedOnLayer( const BOARD_CONNECTED_ITEM *aItem, int aLayer,
                                             std::vector<KICAD_T> aTypes ) const
 {

pcbnew/connectivity/connectivity_data.h

@@ -82,6 +82,15 @@ struct RN_DYNAMIC_LINE
     VECTOR2I a, b;
 };
 
+/**
+ * Controls how nets are propagated through clusters
+ */
+enum class PROPAGATE_MODE
+{
+    SKIP_CONFLICTS,     /// Clusters with conflicting drivers are not updated (default)
+    RESOLVE_CONFLICTS   /// Clusters with conflicting drivers are updated to the most popular net
+};
+
 // a wrapper class encompassing the connectivity computation algorithm and the
 class CONNECTIVITY_DATA
 {
@@ -155,10 +164,12 @@ public:
     RN_NET* GetRatsnestForNet( int aNet );
 
     /**
-     * Function PropagateNets()
      * Propagates the net codes from the source pads to the tracks/vias.
+     * @param aCommit is used to save the undo state of items modified by this call
+     * @param aMode controls how conflicts between pads are resolved
      */
-    void PropagateNets();
+    void PropagateNets( BOARD_COMMIT* aCommit = nullptr,
+                        PROPAGATE_MODE aMode = PROPAGATE_MODE::SKIP_CONFLICTS );
 
     bool CheckConnectivity( std::vector<CN_DISJOINT_NET_ENTRY>& aReport );
 
@@ -202,10 +213,10 @@ public:
      * @param aItem is the reference item to find other connected items.
      * @param aAnchor is the position to find connected items on.
      * @param aTypes allows one to filter by item types.
-     * @return 
+     * @return
      */
     const std::vector<BOARD_CONNECTED_ITEM*> GetConnectedItemsAtAnchor( const BOARD_CONNECTED_ITEM* aItem,
-                                                                        const VECTOR2I& aAnchor, 
+                                                                        const VECTOR2I& aAnchor,
                                                                         const KICAD_T aTypes[] ) const;
 
     void GetUnconnectedEdges( std::vector<CN_EDGE>& aEdges ) const;

pcbnew/netlist_reader/board_netlist_updater.cpp

@@ -1095,6 +1095,7 @@ bool BOARD_NETLIST_UPDATER::UpdateNetlist( NETLIST& aNetlist )
         }
 
         m_board->GetNetInfo().RemoveUnusedNets();
+        m_commit.SetResolveNetConflicts();
         m_commit.Push( _( "Update netlist" ) );
 
         m_board->SynchronizeNetsAndNetClasses();