7z documentation says it can't archive directories, but it can

[Daniel Barrett]

"man 7z" says that 7z cannot archive directories on its own. Under "Backups and limitations," it says:

On Linux/Unix, in order to backup directories you must use tar :
  - to backup a directory : tar cf - directory | 7z a -si directory.tar.7z
  - to restore your backup : 7z x -so directory.tar.7z | tar xf -

This is false. Watch 7z archive a directory:

$ ls -R mydir
mydir:
one subdir/ three two

mydir/subdir:
four

$ 7z a archive mydir
[it works]

$ 7z l archive.7z
...
   Date Time Attr Size Compressed Name
------------------- ----- ------------ ------------ ------------------------
2023-07-05 20:06:00 D.... 0 0 mydir
2023-07-05 20:06:04 D.... 0 0 mydir/subdir
2023-07-05 20:05:56 ....A 4 17 mydir/one
2023-07-05 20:06:04 ....A 4 mydir/subdir/four
2023-07-05 20:05:59 ....A 4 mydir/three
2023-07-05 20:05:57 ....A 4 mydir/two
------------------- ----- ------------ ------------ ------------------------
2023-07-05 20:06:04 16 17 4 files, 2 folders

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: p7zip-full 16.02+dfsg-8
ProcVersionSignature: Ubuntu 5.15.0-76.83-generic 5.15.99
Uname: Linux 5.15.0-76-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Wed Jul 5 20:03:19 2023
InstallationDate: Installed on 2020-02-29 (1222 days ago)
InstallationMedia: Kubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
SourcePackage: p7zip
UpgradeStatus: Upgraded to jammy on 2022-12-03 (214 days ago)