Fix CopyExact to work on a source string

util/copy.go

@@ -15,7 +15,7 @@ func CopyExact(dest interface{}, src interface{}) {
 		panic(fmt.Sprintf("dest not addressable: %T", dest))
 	}
 	if sV.Kind() == reflect.String {
-		sV = sV.Convert(dV.Type())
+		sV = sV.Convert(reflect.SliceOf(dV.Type().Elem()))
 	}
 	if dV.Len() != sV.Len() {
 		panic(fmt.Sprintf("dest len (%d) != src len (%d)", dV.Len(), sV.Len()))

util/copy_test.go

@@ -44,3 +44,18 @@ func TestCopyLenMismatch(t *testing.T) {
 	}()
 	CopyExact(make([]byte, 2), "abc")
 }
+
+func TestCopySrcString(t *testing.T) {
+	dest := make([]byte, 3)
+	CopyExact(dest, "lol")
+	if string(dest) != "lol" {
+		t.FailNow()
+	}
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.FailNow()
+		}
+	}()
+	CopyExact(dest, "rofl")
+}