[Bug-tar] Unchanged directories in listed-incremental level 1

[David]

Using gnu tar 1.22 on ext3 here, every level 1 incremental archive
created contains an entry for every unchanged subdirectory. This
disagrees with the expected behaviour described in the manual. Quoting
from
http://www.gnu.org/software/tar/manual/html_section/Incremental-Dumps.html#SEC94:

"
Some time later you create another incremental backup.  You will then see:
$ tar --create --file=archive.2.tar --listed-incremental=/var/log/usr.snar /usr
tar: usr/local/db: Directory is new
usr/local/db/
usr/local/db/data
usr/local/db/index

The created archive `archive.2.tar' will contain only these three members.
"

Note it says: "only these three members".

However my test script below produces the following output:

$ ./tar_test
top/
top/clean/
top/dirty/
top/empty/
top/dirty/file1

This is inconsistent with the manual example. I expect to see only
top/dirty
top/dirty/file1
in the archive, because the directories top/clean and top/empty did
not change during the test. So why are they present in the level1.tar
file?

This issue makes it difficult to work with my level 1 archives that
contain thousands of these useless empty unchanged directory entries.

Thank you for any assistance to resolve this issue.

---------- script begin ----------
#! /bin/bash

mkdir -p top/dirty top/clean top/empty
touch top/dirty/file1 top/clean/file2
tar --create --file=level0.tar --listed-incremental=snapshot top

sleep 1
date >top/dirty/file1
tar --create --file=level1.tar --listed-incremental=snapshot top
tar --list --file=level1.tar
---------- script end ----------

tar_test
Description: Binary data