Sequencer: Ensure UUIDs are updated when needed

Document cases where it seems that they need to be updated, but where
the proper behavior is to not update the UUID.

1 files changed, 17 insertions, 3 deletions

diff --git a/source/blender/editors/space_sequencer/sequencer_edit.c b/source/blender/editors/space_sequencer/sequencer_edit.c
index 3fbc31d5240..fe851aa16c8 100644
--- a/source/blender/editors/space_sequencer/sequencer_edit.c
+++ b/source/blender/editors/space_sequencer/sequencer_edit.c
@@ -2543,7 +2543,8 @@ static int sequencer_add_duplicate_exec(bContext *C, wmOperator *UNUSED(op))
 
   if (nseqbase.first) {
     Sequence *seq = nseqbase.first;
-    /* Rely on the nseqbase list being added at the end. */
+    /* Rely on the nseqbase list being added at the end.
+     * Their UUIDs has been re-generated by the BKE_sequence_base_dupli_recursive(), */
     BLI_movelisttolist(ed->seqbasep, &nseqbase);
 
     for (; seq; seq = seq->next) {
@@ -2956,6 +2957,7 @@ static int sequencer_meta_make_exec(bContext *C, wmOperator *op)
     if (seq != seqm && (seq->flag & SELECT)) {
       BKE_sequence_invalidate_cache_composite(scene, seq);
       channel_max = max_ii(seq->machine, channel_max);
+      /* Sequence is moved within the same edit, no need to re-generate the UUID. */
       BLI_remlink(ed->seqbasep, seq);
       BLI_addtail(&seqm->seqbase, seq);
     }
@@ -3032,6 +3034,9 @@ static int sequencer_meta_separate_exec(bContext *C, wmOperator *UNUSED(op))
     BKE_sequence_invalidate_cache_composite(scene, seq);
   }
 
+  /* This moves strips from meta to parent, sating within same edit and no new strips are
+   * allocated. If the UUID was unique already (as it should) it will stay unique. Nn need to
+   * re-generate the UUIDs.*/
   BLI_movelisttolist(ed->seqbasep, &last_seq->seqbase);
 
   BLI_listbase_clear(&last_seq->seqbase);
@@ -3371,8 +3376,15 @@ static int sequencer_copy_exec(bContext *C, wmOperator *op)
     return OPERATOR_CANCELLED;
   }
 
-  BKE_sequence_base_dupli_recursive(
-      scene, scene, &seqbase_clipboard, ed->seqbasep, 0, LIB_ID_CREATE_NO_USER_REFCOUNT);
+  /* NOTE: The UUID is re-generated on paste, so we can keep UUID in the clipboard since
+   * nobody can reach them anyway.
+   * This reduces chance or running out of UUIDs if a cat falls asleep on Ctrl-C. */
+  BKE_sequence_base_dupli_recursive(scene,
+                                    scene,
+                                    &seqbase_clipboard,
+                                    ed->seqbasep,
+                                    0,
+                                    (LIB_ID_CREATE_NO_USER_REFCOUNT | LIB_ID_FREE_NO_MAIN));
 
   seqbase_clipboard_frame = scene->r.cfra;
 
@@ -3430,6 +3442,8 @@ static int sequencer_paste_exec(bContext *C, wmOperator *UNUSED(op))
 
   iseq_first = nseqbase.first;
 
+  /* NOTE: BKE_sequence_base_dupli_recursive() takes care of generating new UUIDs for sequences
+   * in the new list. */
   BLI_movelisttolist(ed->seqbasep, &nseqbase);
 
   for (iseq = iseq_first; iseq; iseq = iseq->next) {