m3u8: Ignore empty playlists in check_media_seqnums

Let these error in the immediately following check in gst_m3u8_update.

https://bugzilla.gnome.org/show_bug.cgi?id=788417

1 files changed, 9 insertions, 3 deletions

diff --git a/ext/hls/m3u8.c b/ext/hls/m3u8.c
index 07babd13b..654067cd5 100644
--- a/ext/hls/m3u8.c
+++ b/ext/hls/m3u8.c
@@ -316,6 +316,11 @@ check_media_seqnums (GstM3U8 * self, GList * previous_files)
 
   g_return_val_if_fail (previous_files, FALSE);
 
+  if (!self->files) {
+    /* Empty playlists are trivially consistent */
+    return TRUE;
+  }
+
   /* Find first case of higher/equal sequence number in new playlist or
    * same URI. From there on we can linearly step ahead */
   for (l = self->files; l; l = l->next) {
@@ -334,6 +339,10 @@ check_media_seqnums (GstM3U8 * self, GList * previous_files)
       break;
   }
 
+  /* We must have seen at least one entry on each list */
+  g_assert (f1 != NULL);
+  g_assert (f2 != NULL);
+
   if (!l) {
     /* No match, no sequence in the new playlist was higher than
      * any in the old, and no URI was found again. This is bad! */
@@ -341,9 +350,6 @@ check_media_seqnums (GstM3U8 * self, GList * previous_files)
     return FALSE;
   }
 
-  g_assert (f1 != NULL);
-  g_assert (f2 != NULL);
-
   for (; l && m; l = l->next, m = m->next) {
     f1 = l->data;
     f2 = m->data;