diff --git a/src/nm-core-utils.c b/src/nm-core-utils.c
index 7c36596d0a..2a50f8f816 100644
--- a/src/nm-core-utils.c
+++ b/src/nm-core-utils.c
@@ -3650,7 +3650,8 @@ nm_utils_setpgid (gpointer unused G_GNUC_UNUSED)
 /**
  * nm_utils_g_value_set_strv:
  * @value: a #GValue, initialized to store a #G_TYPE_STRV
- * @strings: a #GPtrArray of strings
+ * @strings: a #GPtrArray of strings. %NULL values are not
+ *   allowed.
  *
  * Converts @strings to a #GStrv and stores it in @value.
  */
@@ -3658,11 +3659,13 @@ void
 nm_utils_g_value_set_strv (GValue *value, GPtrArray *strings)
 {
 	char **strv;
-	int i;
+	guint i;
 
 	strv = g_new (char *, strings->len + 1);
-	for (i = 0; i < strings->len; i++)
+	for (i = 0; i < strings->len; i++) {
+		nm_assert (strings->pdata[i]);
 		strv[i] = g_strdup (strings->pdata[i]);
+	}
 	strv[i] = NULL;
 
 	g_value_take_boxed (value, strv);