Fix: crash when evaluating geometry nodes after deleting an unlinked node

This was essentially a use-after-free issue. When a geometry nodes
group changes it has to be preprocessed again before it can be evaluated.
This part was working, the issue was that parent node groups have to be
preprocessed as well, which was missing. The lazy-function graph cached
on the parent node group was still referencing data that was freed when
the child group changed.

Now the depsgraph makes sure that all relevant geometry node groups are
preprocessed again after a change.

This issue was found by Simon Thommes.

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/depsgraph/intern/node/deg_node_operation.cc b/source/blender/depsgraph/intern/node/deg_node_operation.cc
index 016af735fcf..d5401a6b0d1 100644
--- a/source/blender/depsgraph/intern/node/deg_node_operation.cc
+++ b/source/blender/depsgraph/intern/node/deg_node_operation.cc
@@ -173,6 +173,8 @@ const char *operationCodeAsString(OperationCode opcode)
     /* Node Tree. */
     case OperationCode::NTREE_OUTPUT:
       return "NTREE_OUTPUT";
+    case OperationCode::NTREE_GEOMETRY_PREPROCESS:
+      return "NTREE_GEOMETRY_PREPROCESS";
     /* Movie clip. */
     case OperationCode::MOVIECLIP_EVAL:
       return "MOVIECLIP_EVAL";