Permissions from deb archive are not preserved with non-zero umask

[woky]

The permissions of /tmp directory in base-files packages are 01777:

$ apt-get download base-files
$ ar p base-files_12ubuntu4.1_amd64.deb data.tar.zst | tar --zstd -tvf - ./tmp
drwxrwxrwt root/root         0 2022-04-22 16:34 ./tmp/

However, chisel doesn't preserve it. Specifically, with default umask in Ubuntu, it removes write bit from others:

$ umask
0002
$ chisel cut --release $PWD --root $PWD/output  base-files_base
...
2022/06/17 12:41:53 Fetching pool/main/b/base-files/base-files_12ubuntu4_amd64.deb...
2022/06/17 12:41:53 Extracting files from package "base-files"...
$ ls -ld output/tmp
drwxrwxr-t 2 woky woky 4096 čen 17 12:41 output/tmp

As suggested in canonical/chisel-releases#3 (comment) this is probably an issue with umask. The following works:

$ umask 0
$ chisel cut --release $PWD --root $PWD/output  base-files_base
...
2022/06/17 12:45:30 Fetching pool/main/b/base-files/base-files_12ubuntu4_amd64.deb...
2022/06/17 12:45:30 Extracting files from package "base-files"...
$ ls -ld output/tmp
drwxrwxrwt 2 woky woky 4096 čen 17 12:45 output/tmp