kea-admin lease-upload (2.2.0) invokes kea-lfc without -4 or -6 resulting in misleading error (Unknown argument) if no dhcp version was specified to kea-admin

name: Bug report
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Describe the bug After reading the (concise) documentation of kea-admin https://kea.readthedocs.io/en/kea-2.2.0/arm/admin.html and the command line output reported below, I expected to have briefly understood how to use the lease-upload command, as for example kea-admin lease-upload pgsql -u kea -n database_name -i lease4file.csv gave instead error "Unknown argument."

This is a kea-admin script that conducts administrative tasks on
the Kea installation.

Usage: /usr/local/sbin/kea-admin COMMAND BACKEND [parameters]

COMMAND: Currently supported operations are:

 - db-init: Initializes new database. Useful for first time installation.
 - db-version: Checks version of the existing database schema. Useful
 -             for checking database version when preparing for an upgrade.
 - db-upgrade: Upgrades your database schema.
 - lease-dump: Dumps current leases to a memfile-ready CSV file.
 - lease-upload: Uploads leases from a CSV file to the database.
 - stats-recount: Recounts lease statistics.

BACKEND - one of the supported backends: memfile|mysql|pgsql

PARAMETERS: Parameters are optional in general, but may be required
            for specific operations.
 -h or --host hostname - specifies a hostname of a database to connect to
 -P or --port port - specifies the TCP port to use for the database connection
 -u or --user name - specifies username when connecting to a database
 -p or --password [password] - specifies a password for the database connection;
                               if omitted from the command line,
                               then the user will be prompted for a password
 -n or --name database - specifies a database name to connect to
 -d or --directory - path to upgrade scripts (default: /usr/local/share/kea/scripts)
 -v or --version - print kea-admin version and quit.
 -x or --extra - specifies extra argument(s) to pass to the database command

 Parameters specific to lease-dump, lease-upload:
     -4 to dump IPv4 leases to file
     -6 to dump IPv6 leases to file
     -i or --input to specify the name of file from which leases will be uploaded
     -o or --output to specify the name of file to which leases will be dumped
     -y or --yes - assume yes on overwriting temporary files

To Reproduce Steps to reproduce the behavior:

1. Prepare Kea daemon dhcpv4 using pgsql as in the following config

    "Dhcp4": {
    //...
        "hosts-database": {
            "type": "postgresql",
            "name": "database_name",
            "user": "kea",
            "password": "bugreporting",
            "host": "localhost",
            "port": 5432
        }

start the previously initialized PosgreSQL database service and the kea service. (My environment was OpenBSD 7.3 where I installed PostgreSQL and kea from ports but is probably unrelated)

2. Prepare a valid lease4file.csv (as from /var/lib/kea/kea-leases4.csv)
3. Run: kea-admin lease-upload pgsql -u kea -n database_name -i lease4file.csv
4. See error, it says "Unknown argument"
5. wander what it is (kea-admin invokes kea-lfc with or without the -4 or -6 argument as kea-admin was executed by the user) kea-admin doesn't document clearly that either -4 or -6 is necessary for the lease-upload command, and when not specified it doesn't care to invoke kea-lfc which pretend such argument without saying that clearly either).

Expected behavior At least should say "missing argument" (dhcp version) and the documentation or the code should specify that the kea-admin lease-upload command needs either -4 or -6, because such information is detected by the file nor by the configuration

Environment:

• kea-dhcp4 -V:

2.2.0
tarball
linked with:
log4cplus 1.2.2
LibreSSL 3.7.2
database:
PostgreSQL backend 13.0, library 150002
Memfile backend 2.1

• OS: OpenBSD 7.3
• Which features were compiled in (in particular which backends): port package kea-2.2.0p0-postgresql
• If/which hooks where loaded in: left as default = no hooks/libraries configured yet

Additional Information

Contacting you How can ISC reach you to discuss this matter further? If you do not specify any means such as e-mail, jabber id or a telephone, we may send you a message on github with questions when we have them. I specified the email address while registering in gitlab.isc.org, this requirement of contact details seems to me obsolete, or I might say you can contact me by email. I'm able to write the code to fix the issue which affects new users, not anymore neither me because I did learn the expected (by the command) way to use the command (by debugging, not messages).