Tar extract behaviour changed

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

Somewhere between Netbsd-8 and NetBSD-9 "tar" changed its behaviour
when it has to extract a directory and the path exists as a symlink.

The attached script on -8 gives:

NetBSD 8.0_STABLE

== Initial:
total 8
drwxr-xr-x  2 hannken  staff  512 Oct 21 11:47 realtarget
drwxr-xr-x  2 hannken  staff  512 Oct 21 11:47 target

== Change to symlink:
total 4
drwxr-xr-x  2 hannken  staff  512 Oct 21 11:47 realtarget
lrwxr-xr-x  1 hannken  staff   10 Oct 21 11:47 target -> realtarget

== After extract:
total 4
drwxr-xr-x  2 hannken  staff  512 Oct 21 11:47 realtarget
lrwxr-xr-x  1 hannken  staff   10 Oct 21 11:47 target -> realtarget

On -9 it gives:

NetBSD 9.0_BETA

== Initial:
total 4
drwxr-xr-x  2 root  wheel  512 Oct 21 11:48 realtarget
drwxr-xr-x  2 root  wheel  512 Oct 21 11:48 target

== Change to symlink:
total 2
drwxr-xr-x  2 root  wheel  512 Oct 21 11:48 realtarget
lrwxr-xr-x  1 root  wheel   10 Oct 21 11:48 target -> realtarget

== After extract:
total 4
drwxr-xr-x  2 root  wheel  512 Oct 21 11:48 realtarget
drwxr-xr-x  2 root  wheel  512 Oct 21 11:48 target

Here "target" was changed from symlink to directory.

On NetBSD-9 extracting the "base" set overrides the symlink "/etc/unbound"
with a directory and therefore unbound fails to start.

Is this a bug in "tar" or is there a switch to get the old behaviour back?

--
J. Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig (Germany)

#! /bin/sh

uname -sr
mkdir junk
mkdir junk/target junk/realtarget
printf "\n== Initial:\n" ; ls -l junk
tar -c -f junk.tar junk
rmdir junk/target
ln -s realtarget junk/target
printf "\n== Change to symlink:\n" ; ls -l junk
tar -x -f junk.tar
printf "\n== After extract:\n" ; ls -l junk

rm -rf junk junk.tar