tar -U problem in 1.13.18 through present (1.13.25)

[Richard Fromm]

if i create a sample tar file as such:

11:51pm address@hidden:~/tar/test/nolink> dir
total 8
drwxr-xr-x    2 rfromm   users        4096 Jan  3 22:55 ./
drwxr-xr-x    4 rfromm   users        4096 Jan  3 23:43 ../
-rw-r--r--    1 rfromm   users           0 Jan  3 22:55 foo
11:51pm address@hidden:~/tar/test/nolink> ../../src/tar-1.13.19/src/tar cf 
../nolink.cf.tar .
11:51pm address@hidden:~/tar/test/nolink> 

and then untar it with U there is an error, but without the U it works okay:

12:01am address@hidden:~/tar/out/1.13.19> cd nolink.cf.xUf; 
../../../src/tar-1.13.19/src/tar xUf ../../../test/nolink.cf.tar; cd ..
../../../src/tar-1.13.19/src/tar: ./: Cannot unlink: Is a directory
../../../src/tar-1.13.19/src/tar: Error exit delayed from previous errors
12:01am address@hidden:~/tar/out/1.13.19> cd nolink.cf.xf; 
../../../src/tar-1.13.19/src/tar xf ../../../test/nolink.cf.tar; cd ..
12:02am address@hidden:~/tar/out/1.13.19> 

below are examples of untar'ing with the U flag on everything from 1.13.11
through 1.13.25 (the timestamps are out of order because i didn't try them all
in order).  it appears that a bug was introduced in 1.13.16, and fixed in
1.13.17, and a different bug was introduced in 1.13.18 which continues up until
1.13.25 (the present at the time i did this testing, on 4-jan-2001).

12:08am address@hidden:~/tar/out> cd 1.13.11/nolink.cf.xUf; 
../../../src/tar-1.13.11/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:22am address@hidden:~/tar/out> cd 1.13.12/nolink.cf.xUf; 
../../../src/tar-1.13.12/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:22am address@hidden:~/tar/out> cd 1.13.13/nolink.cf.xUf; 
../../../src/tar-1.13.13/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:22am address@hidden:~/tar/out> cd 1.13.14/nolink.cf.xUf; 
../../../src/tar-1.13.14/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:23am address@hidden:~/tar/out> cd 1.13.15/nolink.cf.xUf; 
../../../src/tar-1.13.15/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:23am address@hidden:~/tar/out> cd 1.13.16/nolink.cf.xUf; 
../../../src/tar-1.13.16/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.16/src/tar: Cannot unlink `.': Invalid argument
../../../src/tar-1.13.16/src/tar: Error exit delayed from previous errors
12:23am address@hidden:~/tar/out> cd 1.13.17/nolink.cf.xUf; 
../../../src/tar-1.13.17/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
12:23am address@hidden:~/tar/out> cd 1.13.18/nolink.cf.xUf; 
../../../src/tar-1.13.18/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.18/src/tar: ./: Cannot unlink: Is a directory
../../../src/tar-1.13.18/src/tar: Error exit delayed from previous errors
12:01am address@hidden:~/tar/out/1.13.19> cd nolink.cf.xUf; 
../../../src/tar-1.13.19/src/tar xUf ../../../test/nolink.cf.tar; cd ..
../../../src/tar-1.13.19/src/tar: ./: Cannot unlink: Is a directory
../../../src/tar-1.13.19/src/tar: Error exit delayed from previous errors
12:32am address@hidden:~/tar/out> cd 1.13.20/nolink.cf.xUf; 
../../../src/tar-1.13.20/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.20/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.20/src/tar: Error exit delayed from previous errors
12:32am address@hidden:~/tar/out> cd 1.13.21/nolink.cf.xUf; 
../../../src/tar-1.13.21/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.21/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.21/src/tar: Error exit delayed from previous errors
12:32am address@hidden:~/tar/out> cd 1.13.22/nolink.cf.xUf; 
../../../src/tar-1.13.22/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.22/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.22/src/tar: Error exit delayed from previous errors
12:32am address@hidden:~/tar/out> cd 1.13.23/nolink.cf.xUf; 
../../../src/tar-1.13.23/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.23/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.23/src/tar: Error exit delayed from previous errors
12:32am address@hidden:~/tar/out> cd 1.13.24/nolink.cf.xUf; 
../../../src/tar-1.13.24/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.24/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.24/src/tar: Error exit delayed from previous errors
12:09am address@hidden:~/tar/out> cd 1.13.25/nolink.cf.xUf; 
../../../src/tar-1.13.25/src/tar xUf ../../../test/nolink.cf.tar; cd ../..
../../../src/tar-1.13.25/src/tar: .: Cannot unlink: Is a directory
../../../src/tar-1.13.25/src/tar: Error exit delayed from previous errors
12:09am address@hidden:~/tar/out> 

sorry if the notation and examples are a little cumbersome looking -- i
investigated a number of different issues before narrowing down the problem to
the U flag.

i could sent the tar file i was using as a testcase, as well as a longer
version of my notes, if that would be helpful.  feel free to contact me if you
have any questions.

- richard fromm
address@hidden