Issue #123 fixed (again)

issue104_test.go

@@ -1,7 +1,6 @@
 package mergo
 
 import (
-	"fmt"
 	"reflect"
 	"testing"
 )
@@ -19,8 +18,6 @@ func StructToRecord(in interface{}) *Record {
 	for i := 0; i < typ.NumField(); i++ {
 		field := typ.Field(i)
 		dbFieldName := field.Tag.Get("db")
-
-		fmt.Printf("%d %v, tags: %v\n", i, field.Name, dbFieldName)
 		if dbFieldName != "" {
 			rec.Mapping[field.Name] = dbFieldName
 		}
@@ -41,7 +38,6 @@ func TestStructToRecord(t *testing.T) {
 	}
 	a := A{Name: "David", CIDR: "10.0.0.0/8"}
 	rec := StructToRecord(a)
-	fmt.Printf("rec: %+v\n", rec)
 	if len(rec.Mapping) < 2 {
 		t.Fatalf("struct to record failed, no mapping, struct missing tags?, rec: %+v, a: %+v ", rec, a)
 	}

merge.go

@@ -119,6 +119,9 @@ func deepMerge(dst, src reflect.Value, visited map[uintptr]*visit, depth int, co
 			switch srcElement.Kind() {
 			case reflect.Chan, reflect.Func, reflect.Map, reflect.Interface, reflect.Slice:
 				if srcElement.IsNil() {
+					if overwrite {
+						dst.SetMapIndex(key, srcElement)
+					}
 					continue
 				}
 				fallthrough