Fix #29384: Mesh without polygons + Modifier crashes when switching to sculpt mode

There were some issues with PBVH which prevented working it for meshes without faces.

Discussed with Brecht, for benefits of dynamic-topology-sculpting and so better to
make PBVH survive such things.

Added some extra NULL-pointer checks for this.

1 files changed, 11 insertions, 3 deletions

diff --git a/source/blender/blenlib/intern/pbvh.c b/source/blender/blenlib/intern/pbvh.c
index 0ac6e0ba4df..5c7a29c6277 100644
--- a/source/blender/blenlib/intern/pbvh.c
+++ b/source/blender/blenlib/intern/pbvh.c
@@ -656,12 +656,17 @@ void BLI_pbvh_free(PBVH *bvh)
 			/* if pbvh was deformed, new memory was allocated for verts/faces -- free it */
 
 			MEM_freeN(bvh->verts);
-			MEM_freeN(bvh->faces);
+			if(bvh->faces)
+				MEM_freeN(bvh->faces);
 		}
 	}
 
-	MEM_freeN(bvh->nodes);
-	MEM_freeN(bvh->prim_indices);
+	if(bvh->nodes)
+		MEM_freeN(bvh->nodes);
+
+	if(bvh->prim_indices)
+		MEM_freeN(bvh->prim_indices);
+
 	MEM_freeN(bvh);
 }
 
@@ -1127,6 +1132,9 @@ void BLI_pbvh_update(PBVH *bvh, int flag, float (*face_nors)[3])
 	PBVHNode **nodes;
 	int totnode;
 
+	if(!bvh->nodes)
+		return;
+
 	BLI_pbvh_search_gather(bvh, update_search_cb, SET_INT_IN_POINTER(flag),
 		&nodes, &totnode);