Fix IPC API losing custom fields when updating footprints

pcbnew/api/api_pcb_utils.cpp

@@ -30,6 +30,7 @@
 #include <pcb_reference_image.h>
 #include <pcb_shape.h>
 #include <pcb_track.h>
+#include <pcb_field.h>
 #include <pcb_text.h>
 #include <pcb_textbox.h>
 #include <zone.h>
@@ -60,6 +61,16 @@ std::unique_ptr<BOARD_ITEM> CreateItemForType( KICAD_T aType, BOARD_ITEM_CONTAIN
         return std::make_unique<PAD>( footprint );
     }
 
+    case PCB_FIELD_T:
+    {
+        FOOTPRINT* footprint = dynamic_cast<FOOTPRINT*>( aContainer );
+
+        if( !footprint )
+            return nullptr;
+
+        return std::make_unique<PCB_FIELD>( footprint, FIELD_T::USER );
+    }
+
     case PCB_FOOTPRINT_T:
     {
         BOARD* board = dynamic_cast<BOARD*>( aContainer );

qa/data/pcbnew/api_kitchen_sink.kicad_pcb

@@ -536,6 +536,19 @@
 				)
 			)
 		)
+		(property "CustomField" "CustomValue"
+			(at 0 0 0)
+			(unlocked yes)
+			(layer "F.Fab")
+			(hide yes)
+			(uuid "212d694f-e13b-46df-9a52-6773137fcf6d")
+			(effects
+				(font
+					(size 1 1)
+					(thickness 0.15)
+				)
+			)
+		)
 		(attr through_hole)
 		(fp_line
 			(start -5.08 3.81)