fix: handle nil network name for bridge/direct interfaces

[ajmeese7]

Problem

When a VM has a bridge or macvtap interface (e.g. from a Vagrant public_network with :dev), libvirt represents it without a source network attribute, so the nic's network name is nil. addresses() took nics.first unconditionally and passed that nil name down to lookup_network_by_name(nil), raising:

TypeError: no implicit conversion of nil into String

This crashed vagrant-libvirt state checks on any VM with a bridge NIC.

Fix

Primary fix is in addresses(): select the first nic that actually has a network instead of blindly taking the first nic. Bridge/direct interfaces have no network name and never carry a libvirt-managed lease, so skipping them both avoids the nil lookup and gives multi-nic VMs a better chance of resolving a real address.

As defense in depth, get_network_by_filter still returns nil early when the name filter is nil, and list_networks compacts the result so Fog::Collection#load never receives a nil entry. This keeps lookup_network_by_name(nil) from raising for any other caller. Happy to drop this layer if you'd rather keep the surface minimal.

Tests

Added minitest coverage for addresses():

• A bridge-only VM (single nic, nil network) returns no address and never performs a network lookup.
• A mixed VM (bridge nic first, NAT nic second) resolves the address from the networked nic.

Fixes vagrant-libvirt state checks crashing on VMs with bridge NICs.

[ekohl]

Please address the RuboCop issue too

[ajmeese7]

Feedback addressed @ekohl

[ekohl]

fog-libvirt's addresses() passes nic.network (nil) to list_networks, which calls lookup_network_by_name(nil), raising:

I'm rereading this now and this is:

fog-libvirt/lib/fog/libvirt/models/compute/server.rb

Lines 475 to 489 in eb3ca30

	# This retrieves the ip address of the mac address using dhcp_leases
	# It returns an array of public and private ip addresses
	# Currently only one ip address is returned, but in the future this could be multiple
	# if the server has multiple network interface
	def addresses(service_arg=service, options={})
	ip_address = nil
	if (nic = self.nics&.first)
	net = service.networks.all(:name => nic.network).first
	# Assume the lease expiring last is the current IP address
	ip_address = net&.dhcp_leases(nic.mac)&.max_by { |lse| lse["expirytime"] }&.dig("ipaddr")
	end
	return { :public => [ip_address], :private => [ip_address] }
	end

In particular:

fog-libvirt/lib/fog/libvirt/models/compute/server.rb

Line 482 in eb3ca30

net = service.networks.all(:name => nic.network).first

Isn't the better fix to try and find the first nic with a network? So:

if (nic = self.nics&.filter { |nic| nic.network }&.first)

That gives a better chance of finding a network that actually has an ip address.

[ajmeese7]

Good call, that's the better fix. Switched to selecting the first nic that has a network in addresses():

if (nic = self.nics&.find { |n| n.network })

Used find rather than filter { }.first to keep RuboCop happy (Style/Detect), and renamed the block var to n so it doesn't shadow the outer nic. I kept the list_networks nil-guard as defense in depth so lookup_network_by_name(nil) can't raise from any other caller, but I can to drop it if you'd rather keep the surface minimal.

[ekohl]

Since you took the effort to write commit messages I don't want to squash for you. Would you mind squashing your commits?

[ajmeese7]

Squashed, thanks for checking!

[ekohl]

Thanks!