Fix T75495: Blender crashes opening a VSE .blend file

During scene copy modifier mask strips are relinked to point to strips in
new scene. If strip used as mask is in different seqbase, this can fail,
if seqbase is not copied yet.

Add SEQ_DUPE_IS_RECURSIVE_CALL flag to avoid relinking modifiers during recursive call.

Reviewed By: brecht

Differential Revision: https://developer.blender.org/D7412

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/sequencer.c b/source/blender/blenkernel/intern/sequencer.c
index 93e5a3bbd74..d3d885fccd9 100644
--- a/source/blender/blenkernel/intern/sequencer.c
+++ b/source/blender/blenkernel/intern/sequencer.c
@@ -5818,7 +5818,7 @@ void BKE_sequence_base_dupli_recursive(const Scene *scene_src,
   Sequence *seqn = NULL;
   Sequence *last_seq = BKE_sequencer_active_get((Scene *)scene_src);
   /* always include meta's strips */
-  int dupe_flag_recursive = dupe_flag | SEQ_DUPE_ALL;
+  int dupe_flag_recursive = dupe_flag | SEQ_DUPE_ALL | SEQ_DUPE_IS_RECURSIVE_CALL;
 
   for (seq = seqbase->first; seq; seq = seq->next) {
     seq->tmp = NULL;
@@ -5844,6 +5844,12 @@ void BKE_sequence_base_dupli_recursive(const Scene *scene_src,
     }
   }
 
+  /* Fix modifier links recursively from the top level only, when all sequences have been
+   * copied. */
+  if (dupe_flag & SEQ_DUPE_IS_RECURSIVE_CALL) {
+    return;
+  }
+
   /* fix modifier linking */
   for (seq = nseqbase->first; seq; seq = seq->next) {
     seq_new_fix_links_recursive(seq);