Fix T46626: Crash generating previews

Brush.toggle_brush was allowed to be an invalid pointer,
it worked for the one operator that used it - but in general bad practice,
requiring a lookup on every access.

Ensure the pointer is kept valid now.

1 files changed, 16 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/brush.c b/source/blender/blenkernel/intern/brush.c
index c2a66adbf92..95b65f52bd0 100644
--- a/source/blender/blenkernel/intern/brush.c
+++ b/source/blender/blenkernel/intern/brush.c
@@ -223,11 +223,27 @@ void BKE_brush_free(Brush *brush)
 		MEM_freeN(brush->gradient);
 }
 
+/**
+ * \note Currently users don't remove brushes from the UI (as is done for scene, text... etc)
+ * This is only used by RNA, which can remove brushes.
+ */
+void BKE_brush_unlink(Main *bmain, Brush *brush)
+{
+	Brush *brush_iter;
+
+	for (brush_iter = bmain->brush.first; brush_iter; brush_iter = brush_iter->id.next) {
+		if (brush_iter->toggle_brush == brush) {
+			brush_iter->toggle_brush = NULL;
+		}
+	}
+}
+
 static void extern_local_brush(Brush *brush)
 {
 	id_lib_extern((ID *)brush->mtex.tex);
 	id_lib_extern((ID *)brush->mask_mtex.tex);
 	id_lib_extern((ID *)brush->clone.image);
+	id_lib_extern((ID *)brush->toggle_brush);
 	id_lib_extern((ID *)brush->paint_curve);
 }