Don't drop text on Edge.Cuts when plotting.

While -our- user model is that Edge.Cuts is just for edges, it's best
not to dictate a particular model to users.

ADDED a DRC error when text (or a dimension) appears on the Edge.Cuts
layer.

Fixes https://gitlab.com/kicad/code/kicad/issues/8470

pcbnew/drc/drc_item.cpp

@@ -57,6 +57,10 @@ DRC_ITEM DRC_ITEM::itemsNotAllowed( DRCE_ALLOWED_ITEMS,
         _( "Items not allowed" ),
         wxT( "items_not_allowed" ) );
 
+DRC_ITEM DRC_ITEM::textOnEdgeCuts( DRCE_TEXT_ON_EDGECUTS,
+        _( "Text (or dimension) on Edge.Cuts layer" ),
+        wxT( "text_on_edge_cuts" ) );
+
 DRC_ITEM DRC_ITEM::clearance( DRCE_CLEARANCE,
         _( "Clearance violation" ),
         wxT( "clearance" ) );
@@ -253,6 +257,7 @@ std::shared_ptr<DRC_ITEM> DRC_ITEM::Create( int aErrorCode )
     case DRCE_UNCONNECTED_ITEMS:        return std::make_shared<DRC_ITEM>( unconnectedItems );
     case DRCE_SHORTING_ITEMS:           return std::make_shared<DRC_ITEM>( shortingItems );
     case DRCE_ALLOWED_ITEMS:            return std::make_shared<DRC_ITEM>( itemsNotAllowed );
+    case DRCE_TEXT_ON_EDGECUTS:         return std::make_shared<DRC_ITEM>( textOnEdgeCuts );
     case DRCE_CLEARANCE:                return std::make_shared<DRC_ITEM>( clearance );
     case DRCE_TRACKS_CROSSING:          return std::make_shared<DRC_ITEM>( tracksCrossing );
     case DRCE_COPPER_EDGE_CLEARANCE:    return std::make_shared<DRC_ITEM>( copperEdgeClearance );

pcbnew/drc/drc_item.h

@@ -36,6 +36,7 @@ enum PCB_DRC_CODE {
     DRCE_UNCONNECTED_ITEMS = DRCE_FIRST, // items are unconnected
     DRCE_SHORTING_ITEMS,                 // items short two nets but are not a net-tie
     DRCE_ALLOWED_ITEMS,                  // a disallowed item has been used
+    DRCE_TEXT_ON_EDGECUTS,               // text or dimension on Edge.Cuts layer
     DRCE_CLEARANCE,                      // items are too close together
     DRCE_TRACKS_CROSSING,                // tracks are crossing
     DRCE_COPPER_EDGE_CLEARANCE,          // a copper item is too close to the board edge
@@ -129,6 +130,7 @@ private:
     static DRC_ITEM unconnectedItems;
     static DRC_ITEM shortingItems;
     static DRC_ITEM itemsNotAllowed;
+    static DRC_ITEM textOnEdgeCuts;
     static DRC_ITEM clearance;
     static DRC_ITEM tracksCrossing;
     static DRC_ITEM copperEdgeClearance;

pcbnew/drc/drc_test_provider_disallow.cpp

@@ -31,6 +31,7 @@
     "Disallow" test. Goes through all items, matching types/conditions drop errors.
     Errors generated:
     - DRCE_ALLOWED_ITEMS
+    - DRCE_TEXT_ON_EDGECUTS
 */
 
 class DRC_TEST_PROVIDER_DISALLOW : public DRC_TEST_PROVIDER
@@ -64,18 +65,6 @@ public:
 
 bool DRC_TEST_PROVIDER_DISALLOW::Run()
 {
-    if( m_drcEngine->IsErrorLimitExceeded( DRCE_ALLOWED_ITEMS ) )
-    {
-        reportAux( "Disallow violations ignored. Tests not run." );
-        return true;    // continue with other tests
-    }
-
-    if( !m_drcEngine->HasRulesForConstraintType( DISALLOW_CONSTRAINT ) )
-    {
-        reportAux( "No disallow constraints found. Skipping check." );
-        return true;    // continue with other tests
-    }
-
     if( !reportPhase( _( "Checking keepouts & disallow constraints..." ) ) )
         return false;   // DRC cancelled
 
@@ -103,6 +92,28 @@ bool DRC_TEST_PROVIDER_DISALLOW::Run()
     auto checkItem =
             [&]( BOARD_ITEM* item ) -> bool
             {
+                if( !m_drcEngine->IsErrorLimitExceeded( DRCE_TEXT_ON_EDGECUTS )
+                        && item->GetLayer() == Edge_Cuts )
+                {
+                    switch( item->Type() )
+                    {
+                    case PCB_TEXT_T:
+                    case PCB_DIM_ALIGNED_T:
+                    case PCB_DIM_CENTER_T:
+                    case PCB_DIM_ORTHOGONAL_T:
+                    case PCB_DIM_LEADER_T:
+                    {
+                        std::shared_ptr<DRC_ITEM> drc = DRC_ITEM::Create( DRCE_TEXT_ON_EDGECUTS );
+                        drc->SetItems( item );
+                        reportViolation( drc, item->GetPosition() );
+                    }
+                        break;
+
+                    default:
+                        break;
+                    }
+                }
+
                 if( m_drcEngine->IsErrorLimitExceeded( DRCE_ALLOWED_ITEMS ) )
                     return false;
 

pcbnew/plot_brditems_plotter.cpp

@@ -348,18 +348,14 @@ void BRDITEMS_PLOTTER::PlotBoardGraphicItems()
             break;
 
         case PCB_TEXT_T:
-            if( item->GetLayer() != Edge_Cuts )
             PlotPcbText( (PCB_TEXT*) item );
-
             break;
 
         case PCB_DIM_ALIGNED_T:
         case PCB_DIM_CENTER_T:
         case PCB_DIM_ORTHOGONAL_T:
         case PCB_DIM_LEADER_T:
-            if( item->GetLayer() != Edge_Cuts )
             PlotDimension( (DIMENSION_BASE*) item );
-
             break;
 
         case PCB_TARGET_T: