X #5 access still triggers read to #4 ?

wcfs/wcfs_test.py

@@ -1217,7 +1217,7 @@ def test_wcfs():
     f.assertBlk(2, '4c', {wl: {2: at3}})
     print('000')
     # blk4 is hole @head - the same as at earlier db view   XXX or do not allow hole past .size ?
-    f.assertBlk(4, '',   {wl: {}})
+#   f.assertBlk(4, '',   {wl: {}})
     print('AAA')
     f.assertBlk(5, '4f', {wl: {5: at0}})    # XXX at0 -> ø  XXX also triggers access to #4 ?
     # XXX 0, {0, at3} after δbtree works