debugutils: Handle caps field values being NULL

GST_DEBUG_BIN_TO_DOT_FILE() would cause a segfault whenever it encountered an
element's caps that had a field value being NULL. Such fields are successfully
handled e.g. by GST_*_OBJECT(), and with this patch so does
GST_DEBUG_BIN_TO_DOT_FILE(). Even if string fields with a NULL value are
not supposed to be valid in caps, such caps can be created.

Fixes https://bugzilla.gnome.org/show_bug.cgi?id=727701

diff --git a/gst/gstdebugutils.c b/gst/gstdebugutils.c
index 0beaf99..7b3ebf9 100644 (file)
--- a/gst/gstdebugutils.c
+++ b/gst/gstdebugutils.c
@@ -273,6 +273,11 @@ string_append_field (GQuark field, const GValue * value, gpointer ptr)
   gchar *value_str = gst_value_serialize (value);
   gchar *esc_value_str;
 
+  if (value_str == NULL) {
+    g_string_append_printf (str, "  %18s: NULL\\l", g_quark_to_string (field));
+    return TRUE;
+  }
+
   /* some enums can become really long */
   if (strlen (value_str) > 25) {
     gint pos = 24;