Fix T81594: Unable to reassign effect inputs

This was caused by canceling operator if strip has more than 0 inputs.
Logic should be reversed - cancel only if strip has 0 inputs.

BKE_sequencer_render_loop_check() arguments had to be sanitized because
seq_effect_find_selected() can set seq1,2,3 to NULL

Reviewed By: sergey

Differential Revision: https://developer.blender.org/D9197

2 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/editors/space_sequencer/sequencer_edit.c b/source/blender/editors/space_sequencer/sequencer_edit.c
index e446a1a5ed7..8a705ef49dd 100644
--- a/source/blender/editors/space_sequencer/sequencer_edit.c
+++ b/source/blender/editors/space_sequencer/sequencer_edit.c
@@ -2134,7 +2134,7 @@ static int sequencer_reassign_inputs_exec(bContext *C, wmOperator *op)
   Sequence *seq1, *seq2, *seq3, *last_seq = BKE_sequencer_active_get(scene);
   const char *error_msg;
 
-  if (BKE_sequence_effect_get_num_inputs(last_seq->type) != 0) {
+  if (BKE_sequence_effect_get_num_inputs(last_seq->type) == 0) {
     BKE_report(op->reports, RPT_ERROR, "Cannot reassign inputs: strip has no inputs");
     return OPERATOR_CANCELLED;
   }
diff --git a/source/blender/sequencer/intern/sequencer.c b/source/blender/sequencer/intern/sequencer.c
index cb62ffe500b..2e38c478905 100644
--- a/source/blender/sequencer/intern/sequencer.c
+++ b/source/blender/sequencer/intern/sequencer.c
@@ -6085,6 +6085,10 @@ bool BKE_sequencer_check_scene_recursion(Scene *scene, ReportList *reports)
 /* Check if "seq_main" (indirectly) uses strip "seq". */
 bool BKE_sequencer_render_loop_check(Sequence *seq_main, Sequence *seq)
 {
+  if (seq_main == NULL || seq == NULL) {
+    return false;
+  }
+
   if (seq_main == seq) {
     return true;
   }