awg-quick crashes when i1–i5 parameters are empty (AmneziaWG v2 protocol) #40

Hi, I'm getting an error when trying to bring up an AmneziaWG v2 interface on Linux using a config exported from Amnezia self-hosted.

The config has Jc, Jmin, Jmax, S1, S2, H1–H4 set, but I1–I5 come out empty from the export:

[Interface]
PrivateKey = <key>
Address =
DNS = 1.1.1.1
Jc = 4
Jmin = 40
Jmax = 70
S1 = 0
S2 = 0
H1 = 1
H2 = 2
H3 = 3
H4 = 4
I1 = <b 0x084481800001000300000000077469636b...
I2 = 
I3 =
I4 =
I5 =

[Peer]
PublicKey = <key>
AllowedIPs = 0.0.0.0/0
Endpoint = <host>:<port>

Running awg-quick up awg0 fails. After some digging I found the issue in awg-quick — empty I1–I5 values are silently dropped and never passed to awg setconf:

I1|I2|I3|I4|I5) [[ -n $value ]] && WG_CONFIG+="$line"$'\n'; continue ;;

So awg setconf gets a config without those fields and chokes on it. No warning is printed, which makes it hard to debug.

This seems to affect anyone exporting configs from Amnezia self-hosted since that's where the empty I1–I5 come from.