pcbnew crash while opening old .brd file

Fixes: lp:1698697
https://bugs.launchpad.net/kicad/+bug/1698697

The incorrect method ZONE_CONTAINER::AppendCorner() is also fixed:
It was expecting the corner must be added to the main outline, but this is a false expectation:
it can be added to a hole inside the zone outline.

pcbnew/class_board.cpp

@@ -2348,21 +2348,24 @@ void BOARD::RemoveArea( PICKED_ITEMS_LIST* aDeletedList, ZONE_CONTAINER* area_to
 }
 
 
-ZONE_CONTAINER* BOARD::InsertArea( int netcode, int iarea, PCB_LAYER_ID layer, int x, int y, int hatch )
+ZONE_CONTAINER* BOARD::InsertArea( int aNetcode, int aAreaIdx, PCB_LAYER_ID aLayer,
+                                   int aCornerX, int aCornerY, int aHatch )
 {
     ZONE_CONTAINER* new_area = new ZONE_CONTAINER( this );
 
-    new_area->SetNetCode( netcode );
-    new_area->SetLayer( layer );
+    new_area->SetNetCode( aNetcode );
+    new_area->SetLayer( aLayer );
     new_area->SetTimeStamp( GetNewTimeStamp() );
 
-    if( iarea < (int) ( m_ZoneDescriptorList.size() - 1 ) )
-        m_ZoneDescriptorList.insert( m_ZoneDescriptorList.begin() + iarea + 1, new_area );
+    if( aAreaIdx < (int) ( m_ZoneDescriptorList.size() - 1 ) )
+        m_ZoneDescriptorList.insert( m_ZoneDescriptorList.begin() + aAreaIdx + 1, new_area );
     else
         m_ZoneDescriptorList.push_back( new_area );
 
-    new_area->SetHatchStyle( (ZONE_CONTAINER::HATCH_STYLE) hatch );
-    new_area->AppendCorner( wxPoint( x, y ) );
+    new_area->SetHatchStyle( (ZONE_CONTAINER::HATCH_STYLE) aHatch );
+
+    // Add the first corner to the new zone
+    new_area->AppendCorner( wxPoint( aCornerX, aCornerY ), -1 );
 
     return new_area;
 }

pcbnew/class_board.h

@@ -1070,11 +1070,17 @@ public:
                              PCB_LAYER_ID aLayer, wxPoint aStartPointPosition, int aHatch );
 
     /**
-     * Function InsertArea
-     * add empty copper area to net, inserting after m_ZoneDescriptorList[iarea]
+     * Add a copper area to net, inserting after m_ZoneDescriptorList[aAreaIdx]
+     * @param aNetcode is the netcode of the new copper zone
+     * @param aAreaIdx is the netcode of the new copper zone
+     * @param aLayer is the copper layer id of the new copper zone
+     * @param aCornerX,aCornerY is the coordinate of the first corner
+     * (a zone cannot have a empty outline)
+     * @param aHatch is the hatch option
      * @return pointer to the new area
      */
-    ZONE_CONTAINER* InsertArea( int netcode, int iarea, PCB_LAYER_ID layer, int x, int y, int hatch );
+    ZONE_CONTAINER* InsertArea( int aNetcode, int aAreaIdx, PCB_LAYER_ID aLayer,
+                                int aCornerX, int aCornerY, int aHatch );
 
     /**
      * Function NormalizeAreaPolygon

pcbnew/class_zone.cpp

@@ -843,6 +843,24 @@ void ZONE_CONTAINER::AddPolygon( std::vector< wxPoint >& aPolygon )
 }
 
 
+bool ZONE_CONTAINER::AppendCorner( wxPoint aPosition, int aHoleIdx, bool aAllowDuplication )
+{
+    // Ensure the main outline exists:
+    if( m_Poly->OutlineCount() == 0 )
+        m_Poly->NewOutline();
+
+    // If aHoleIdx >= 0, the corner musty be added to the hole, index aHoleIdx.
+    // (remember: the index of the first hole is 0)
+    // Return error if if does dot exist.
+    if( aHoleIdx >= m_Poly->HoleCount( 0 ) )
+        return false;
+
+    m_Poly->Append( aPosition.x, aPosition.y, -1, aHoleIdx, aAllowDuplication );
+
+    return true;
+}
+
+
 wxString ZONE_CONTAINER::GetSelectMenuText() const
 {
     wxString text;

pcbnew/class_zone.h

@@ -537,18 +537,14 @@ public:
     }
 
     /**
-     * Function AppendCorner
-     * @param position          is the position of the new corner.
+     * Add a new corner to the zone outline (to the main outline or a hole)
+     * @param aPosition         is the position of the new corner.
+     * @param aHoleIdx          is the index of the hole (-1 for the main outline, >= 0 for hole).
      * @param aAllowDuplication is a flag to indicate whether it is allowed to add this corner
      *                          even if it is duplicated.
+     * @return true if the corner was added, false if error (aHoleIdx > hole count -1)
      */
-    void AppendCorner( wxPoint position, bool aAllowDuplication = false )
-    {
-        if( m_Poly->OutlineCount() == 0 )
-            m_Poly->NewOutline();
-
-        m_Poly->Append( position.x, position.y, -1, -1, aAllowDuplication );
-    }
+    bool AppendCorner( wxPoint aPosition, int aHoleIdx, bool aAllowDuplication = false );
 
     HATCH_STYLE GetHatchStyle() const
     {

pcbnew/eagle_plugin.cpp

@@ -621,10 +621,11 @@ void EAGLE_PLUGIN::loadPlain( wxXmlNode* aGraphics )
 
                 ZONE_CONTAINER::HATCH_STYLE outline_hatch = ZONE_CONTAINER::DIAGONAL_EDGE;
 
-                zone->AppendCorner( wxPoint( kicad_x( r.x1 ), kicad_y( r.y1 ) ) );
-                zone->AppendCorner( wxPoint( kicad_x( r.x2 ), kicad_y( r.y1 ) ) );
-                zone->AppendCorner( wxPoint( kicad_x( r.x2 ), kicad_y( r.y2 ) ) );
-                zone->AppendCorner( wxPoint( kicad_x( r.x1 ), kicad_y( r.y2 ) ) );
+                const int outlineIdx = -1;      // this is the id of the copper zone main outline
+                zone->AppendCorner( wxPoint( kicad_x( r.x1 ), kicad_y( r.y1 ) ), outlineIdx );
+                zone->AppendCorner( wxPoint( kicad_x( r.x2 ), kicad_y( r.y1 ) ), outlineIdx );
+                zone->AppendCorner( wxPoint( kicad_x( r.x2 ), kicad_y( r.y2 ) ), outlineIdx );
+                zone->AppendCorner( wxPoint( kicad_x( r.x1 ), kicad_y( r.y2 ) ), outlineIdx );
 
                 // this is not my fault:
                 zone->SetHatch( outline_hatch, Mils2iu( zone->GetDefaultHatchPitchMils() ), true );
@@ -1812,7 +1813,7 @@ void EAGLE_PLUGIN::loadSignals( wxXmlNode* aSignals )
                         EVERTEX v( vertex );
 
                         // Append the corner
-                        zone->AppendCorner( wxPoint( kicad_x( v.x ), kicad_y( v.y ) ) );
+                        zone->AppendCorner( wxPoint( kicad_x( v.x ), kicad_y( v.y ) ), -1 );
 
                         vertex = vertex->GetNext();
                     }

pcbnew/legacy_plugin.cpp

@@ -2475,7 +2475,8 @@ void LEGACY_PLUGIN::loadZONE_CONTAINER()
     unique_ptr<ZONE_CONTAINER> zc( new ZONE_CONTAINER( m_board ) );
 
     ZONE_CONTAINER::HATCH_STYLE outline_hatch = ZONE_CONTAINER::NO_HATCH;
-    bool    sawCorner = false;
+    bool    endContour = false;
+    int     holeIndex = -1;     // -1 is the main outline; holeIndex >= 0 = hole index
     char    buf[1024];
     char*   line;
     char*   saveptr;
@@ -2484,18 +2485,27 @@ void LEGACY_PLUGIN::loadZONE_CONTAINER()
     {
         const char* data;
 
-        if( TESTLINE( "ZCorner" ) )         // new corner found
+        if( TESTLINE( "ZCorner" ) ) // new corner of the zone outlines found
         {
             // e.g. "ZCorner 25650 49500 0"
             BIU x    = biuParse( line + SZ( "ZCorner" ), &data );
             BIU y    = biuParse( data, &data );
 
-            if( !sawCorner )
+            if( endContour )
+            {
+                // the previous corner was the last corner of a contour.
+                // so this corner is the first of a new hole
+                endContour = false;
                 zc->NewHole();
-            else
-                zc->AppendCorner( wxPoint( x, y ) );
+                holeIndex++;
+            }
+
+            zc->AppendCorner( wxPoint( x, y ), holeIndex );
 
-            sawCorner = true;
+            // Is this corner the end of current contour?
+            // the next corner (if any) will be stored in a new contour (a hole)
+            // intParse( data )returns 0 = usual corner, 1 = last corner of the current contour:
+            endContour = intParse( data );
         }
 
         else if( TESTLINE( "ZInfo" ) )      // general info found
@@ -2655,7 +2665,7 @@ void LEGACY_PLUGIN::loadZONE_CONTAINER()
 
         else if( TESTLINE( "$POLYSCORNERS" ) )
         {
-            // Read the PolysList (polygons used for fill areas in the zone)
+            // Read the PolysList (polygons that are the solid areas in the filled zone)
             SHAPE_POLY_SET polysList;
 
             bool makeNewOutline = true;

pcbnew/pcad2kicadpcb_plugin/pcb_polygon.cpp

@@ -182,7 +182,7 @@ void PCB_POLYGON::AddToBoard()
         for( i = 0; i < (int) m_outline.GetCount(); i++ )
         {
             zone->AppendCorner( wxPoint( KiROUND( m_outline[i]->x ),
-                                         KiROUND( m_outline[i]->y ) ) );
+                                         KiROUND( m_outline[i]->y ) ), -1 );
         }
 
         zone->SetZoneClearance( m_width );
@@ -206,7 +206,6 @@ void PCB_POLYGON::AddToBoard()
         }
 
         //if( m_filled )
-        //    cvpcb is not linked
         //    zone->BuildFilledPolysListData( m_board );
     }
 }

pcbnew/zones_by_polygon.cpp

@@ -669,8 +669,9 @@ int PCB_EDIT_FRAME::Begin_Zone( wxDC* DC )
         zone->SetLayer( zoneInfo.m_CurrentZone_Layer );
 
         // A duplicated corner is needed; null segments are removed when the zone is finished.
-        zone->AppendCorner( GetCrossHairPosition() );
-        zone->AppendCorner( GetCrossHairPosition(), true );
+        zone->AppendCorner( GetCrossHairPosition(), -1 );
+        // Add the duplicate corner:
+        zone->AppendCorner( GetCrossHairPosition(), -1, true );
 
         if( g_Drc_On && (m_drc->Drc( zone, 0 ) == BAD_DRC) && zone->IsOnCopperLayer() )
         {