diff --git a/gio/gvdb/gvdb-reader.c b/gio/gvdb/gvdb-reader.c
index aa3154feb..95093885f 100644
--- a/gio/gvdb/gvdb-reader.c
+++ b/gio/gvdb/gvdb-reader.c
@@ -332,7 +332,7 @@ gvdb_table_list_from_item (GvdbTable                    *table,
 /**
  * gvdb_table_get_names:
  * @table: a #GvdbTable
- * @length: the number of items returned, or %NULL
+ * @length: (optional): the number of items returned, or %NULL
  *
  * Gets a list of all names contained in @table.
  *
@@ -344,11 +344,11 @@ gvdb_table_list_from_item (GvdbTable                    *table,
  * above calls in the case of the corrupted file.  Note also that the
  * returned strings may not be utf8.
  *
- * Returns: a %NULL-terminated list of strings, of length @length
+ * Returns: (array length=length): a %NULL-terminated list of strings, of length @length
  **/
 gchar **
 gvdb_table_get_names (GvdbTable *table,
-                      gint      *length)
+                      gsize     *length)
 {
   gchar **names;
   gint n_names;
@@ -462,7 +462,7 @@ gvdb_table_get_names (GvdbTable *table,
     {
       GPtrArray *fixed_names;
 
-      fixed_names = g_ptr_array_new ();
+      fixed_names = g_ptr_array_sized_new (n_names);
       for (i = 0; i < n_names; i++)
         if (names[i] != NULL)
           g_ptr_array_add (fixed_names, names[i]);
@@ -474,7 +474,10 @@ gvdb_table_get_names (GvdbTable *table,
     }
 
   if (length)
-    *length = n_names;
+    {
+      G_STATIC_ASSERT (sizeof (*length) >= sizeof (n_names));
+      *length = n_names;
+    }
 
   return names;
 }
diff --git a/gio/gvdb/gvdb-reader.h b/gio/gvdb/gvdb-reader.h
index 39827737d..79a97d358 100644
--- a/gio/gvdb/gvdb-reader.h
+++ b/gio/gvdb/gvdb-reader.h
@@ -22,40 +22,55 @@
 
 #include <glib.h>
 
+/* We cannot enable the weak attribute unconditionally here because both
+ * gvdb/gvdb-reader.c and tests/dconf-mock-gvdb.c include this file. The
+ * intention of using weak symbols here is to allow the latter to override
+ * functions defined in the former, so functions in tests/dconf-mock-gvdb.c
+ * must have strong bindings. */
+#ifdef GVDB_USE_WEAK_SYMBOLS
+# ifdef __GNUC__
+#  define GVDB_GNUC_WEAK __attribute__((weak))
+# else
+#  define GVDB_GNUC_WEAK
+# endif
+#else
+# define GVDB_GNUC_WEAK
+#endif
+
 typedef struct _GvdbTable GvdbTable;
 
 G_BEGIN_DECLS
 
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_new_from_bytes                       (GBytes       *bytes,
                                                                          gboolean      trusted,
                                                                          GError      **error);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_new                                  (const gchar  *filename,
                                                                          gboolean      trusted,
                                                                          GError      **error);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 void                    gvdb_table_free                                 (GvdbTable    *table);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gchar **                gvdb_table_get_names                            (GvdbTable    *table,
-                                                                         gint         *length);
-G_GNUC_INTERNAL
+                                                                         gsize        *length);
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gchar **                gvdb_table_list                                 (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GvdbTable *             gvdb_table_get_table                            (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GVariant *              gvdb_table_get_raw_value                        (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 GVariant *              gvdb_table_get_value                            (GvdbTable    *table,
                                                                          const gchar  *key);
 
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gboolean                gvdb_table_has_value                            (GvdbTable    *table,
                                                                          const gchar  *key);
-G_GNUC_INTERNAL
+G_GNUC_INTERNAL GVDB_GNUC_WEAK
 gboolean                gvdb_table_is_valid                             (GvdbTable    *table);
 
 G_END_DECLS