I came across that issue when I tried to get the "sshtunnel" package configured.
My minimal config looks as follows:
config server vpn1
option user sshtunnel
option hostname 'myhost.doman.tld'
option port 22
option IdentityFile '/root/.ssh/server.sshtunnel.id_rsa'
#config tunnelR owrt-https
# option server vpn1
# option remoteaddress '*'
# option remoteport 31443
# option localaddress '192.168.100.1'
# option localport 443
When I do a
root@wrt# validate_data "sshtunnel" "server" "vpn1" 'user:string(1)'
sshtunnel.nas2.user=sshtunnel validates as string(1) with true
user='sshtunnel';
root@wrt# echo $?
0
the validation works ok as expected.
But as soon as I uncomment the 2nd section in the config, then it raises an error:
root@wrt# validate_data "sshtunnel" "server" "vpn1" 'user:string(1)'
root@wrt# echo $?
255
The validation should stil be good as I only request to validate the section "server" for "vpn1" and nothing is changed there compated to the 1st attempt.
I tested this on 23.05 and 23.05.02, platform ath79/generic, build OpenWrt 23.05.2 r23630-842932a63d / LuCI openwrt-23.05 branch git-23.306.39416-c86c256