From 4eba781013ddc60a8b525c20a03d18aafe895a52 Mon Sep 17 00:00:00 2001
From: Jon Evans <jon@craftyjon.com>
Date: Sat, 10 Feb 2024 23:26:25 -0500
Subject: [PATCH] Try harder to remove stale pins from connectivity

Fixes https://gitlab.com/kicad/code/kicad/-/issues/16846
---
 eeschema/connection_graph.cpp | 29 +++++++++++++++++++++++++++++
 eeschema/connection_graph.h   |  2 ++
 eeschema/sch_commit.cpp       |  9 +++++++++
 3 files changed, 40 insertions(+)

diff --git a/eeschema/connection_graph.cpp b/eeschema/connection_graph.cpp
index e8c9491817..5056dcb257 100644
--- a/eeschema/connection_graph.cpp
+++ b/eeschema/connection_graph.cpp
@@ -734,6 +734,14 @@ std::set<std::pair<SCH_SHEET_PATH, SCH_ITEM*>> CONNECTION_GRAPH::ExtractAffected
         }
 
         alg::delete_matching( m_items, item );
+
+        if( item->Type() == SCH_SYMBOL_T )
+        {
+            SCH_SYMBOL* symbol = static_cast<SCH_SYMBOL*>( item );
+
+            for( SCH_PIN* pin : symbol->GetPins( &sg->m_sheet ) )
+                alg::delete_matching( m_items, pin );
+        }
     }
 
     removeSubgraphs( subgraphs );
@@ -742,6 +750,24 @@ std::set<std::pair<SCH_SHEET_PATH, SCH_ITEM*>> CONNECTION_GRAPH::ExtractAffected
 }
 
 
+void CONNECTION_GRAPH::RemoveItem( SCH_ITEM* aItem )
+{
+    auto it = m_item_to_subgraph_map.find( aItem );
+
+    if( it == m_item_to_subgraph_map.end() )
+        return;
+
+    CONNECTION_SUBGRAPH* subgraph = it->second;
+
+    while(subgraph->m_absorbed_by )
+        subgraph = subgraph->m_absorbed_by;
+
+    subgraph->RemoveItem( aItem );
+    alg::delete_matching( m_items, aItem );
+    m_item_to_subgraph_map.erase( it );
+}
+
+
 void CONNECTION_GRAPH::removeSubgraphs( std::set<CONNECTION_SUBGRAPH*>& aSubgraphs )
 {
     std::sort( m_driver_subgraphs.begin(), m_driver_subgraphs.end() );
@@ -906,6 +932,9 @@ void CONNECTION_GRAPH::updateItemConnectivity( const SCH_SHEET_PATH& aSheet,
 
     for( SCH_ITEM* item : aItemList )
     {
+        if( item->Type() == SCH_PIN_T )
+            std::cout << "conn updateItemConnectivity " << item << std::endl;
+
         std::vector<VECTOR2I> points = item->GetConnectionPoints();
         item->ConnectedItems( aSheet ).clear();
 
diff --git a/eeschema/connection_graph.h b/eeschema/connection_graph.h
index cbf0bd64c8..f0ab387f4c 100644
--- a/eeschema/connection_graph.h
+++ b/eeschema/connection_graph.h
@@ -452,6 +452,8 @@ public:
      */
     void Merge( CONNECTION_GRAPH& aGraph );
 
+    void RemoveItem( SCH_ITEM* aItem );
+
 private:
     /**
      * Update the graphical connectivity between items (i.e. where they touch)
diff --git a/eeschema/sch_commit.cpp b/eeschema/sch_commit.cpp
index b6bcd94a34..de5b823d58 100644
--- a/eeschema/sch_commit.cpp
+++ b/eeschema/sch_commit.cpp
@@ -33,6 +33,7 @@
 
 #include <view/view.h>
 #include <sch_commit.h>
+#include <connection_graph.h>
 
 #include <functional>
 
@@ -533,6 +534,14 @@ void SCH_COMMIT::Revert()
             {
                 SCH_SYMBOL* symbol = static_cast<SCH_SYMBOL*>( item );
                 symbol->UpdatePins();
+
+                CONNECTION_GRAPH* graph = schematic->ConnectionGraph();
+
+                SCH_SYMBOL* symbolCopy = static_cast<SCH_SYMBOL*>( copy );
+                graph->RemoveItem( symbolCopy );
+
+                for( SCH_PIN* pin : symbolCopy->GetPins() )
+                    graph->RemoveItem( pin );
             }
 
             item->SetConnectivityDirty();