Nil dereference in CheckServers/getServerList

[dynajoe]

I was starting a consul agent for the first time minutes after being created and ran into a nil dereference here:

consul/agent/router/manager.go

Line 253 in 37cafc3

return m.listValue.Load().(serverList)

The stack trace included:

consul/agent/router/manager.go

Line 246 in 37cafc3

func (m *Manager) CheckServers(fn func(srv *metadata.Server) bool) {

==> Starting Consul agent...
           Version: 'v1.7.3'
           Node ID: 'xxxx'
         Node name: 'xxxx'
        Datacenter: 'dc1' (Segment: '')
            Server: false (Bootstrap: false)
       Client Addr: [127.0.0.1] (HTTP: 8500, HTTPS: -1, gRPC: -1, DNS: 8600)
      Cluster Addr: xxx.xxxx.xxx.xxx (LAN: 8301, WAN: 8302)
           Encrypt: Gossip: true, TLS-Outgoing: true, TLS-Incoming: false, Auto-Encrypt-TLS: true

==> Log data will now stream in as it occurs:

... missing stack trace here ...

Unfortunately, my scroll back isn’t long enough and I lost the actual stack trace.

Launching the agent again did not present the issue.

consul agent version: 1.7.3
command: ./consul agent -config-file config.json -data-dir=/tmp/consul
config:

{
    "acl": {
        "enabled": true,
        "down_policy": "async-cache",
        "default_policy": "deny"
    },
    "ca_file": "./ca.pem",
    "verify_outgoing": true,
    "datacenter": "dc1",
    "encrypt": "xxxx",
    "server": false,
    "log_level": "INFO",
    "ui": true,
    "retry_join": [
        "xxxxx"
    ],
    "auto_encrypt": {
        "tls": true
    }
}

OS: Linux 4.4.0-1105-aws #116-Ubuntu SMP Wed Mar 18 05:11:57 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux