Fix T44439: outliner's treestore could keep invalid ID pointers, could crash on undo due to invalid mem access.

We cannot nuke treestore in readfile's `blo_lib_link_screen_restore()`, because this will
destroy all UI-state data (like opened/closed items, etc.).

Since we cannot know for sure whether an ID pointer from tselem->id is valid here, we
have to ensure they are never invalid, i.e. to always set them to NULL when we delete them.

To do so, this commit uses a similar approach as what already exists for ID references
in WM notifiers - it extends `free_notifier_reference_cb()` to also nullify those IDs in
all outliners.

Note that some ID types are not used(shown) by outliner currently, so `TREESTORE_ID_TYPE` macro
was added, that checks whether an ID is possibly used by outliner. Avoids a few searches
in whole tree whene deleting some IDs.

Reviewers: campbellbarton, sergey

Maniphest Tasks: T44439

Differential Revision: https://developer.blender.org/D1272

1 files changed, 5 insertions, 0 deletions

diff --git a/source/blender/editors/space_outliner/outliner_tree.c b/source/blender/editors/space_outliner/outliner_tree.c
index 17a6e952ee1..4b07c400220 100644
--- a/source/blender/editors/space_outliner/outliner_tree.c
+++ b/source/blender/editors/space_outliner/outliner_tree.c
@@ -855,6 +855,11 @@ static TreeElement *outliner_add_element(SpaceOops *soops, ListBase *lb, void *i
 		return NULL;
 	}
 
+	if (type == 0) {
+		/* Zero type means real ID, ensure we do not get non-outliner ID types here... */
+		BLI_assert(TREESTORE_ID_TYPE(id));
+	}
+
 	te = MEM_callocN(sizeof(TreeElement), "tree elem");
 	/* add to the visual tree */
 	BLI_addtail(lb, te);