gnome-boxes reset VM network config on start

[Kirill Malgichev]

I am trying to configure bridged network (switch from default NAT to bridged conction) for one of VMs created by gnome-boxes app.

Here is my steps:
1. $ virsh -c qemu:///session edit ubuntu18.04 and change

  <interface type='user'>
        <mac address='52:54:00:41:f7:ed'/>
        <model type='virtio'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
  </interface>

  to

  <interface type='network'>
        <mac address='52:54:00:41:f7:ed'/>
        <source network='virbr1'/>
        <model type='virtio'/>
        <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
  </interface>

2. $ virsh -c qemu:///session start ubuntu18.04
Domain ubuntu18.04 started

3. $ virsh -c qemu:///session domiflist ubuntu18.04
Interface Type Source Model MAC
-------------------------------------------------------
tap0 bridge virbr1 virtio 52:54:00:41:f7:ed

So, ubuntu18.04 VM gets external IP address and can be accessed from other PCs in the network. My problem is that configuration resets back to "user" or NAT network (with new mac address) each time gnome-boxes application started. In rare cases my "bridged network" configuration can survive gnome-boxes startup but will be reset back to defaults after VM shutdown.

Same behavior when using virt-manager to configure networking.

-----
$ lsb_release -rd
Description: Ubuntu 18.04.3 LTS
Release: 18.04

$ apt-cache policy gnome-boxes
gnome-boxes:
  Installed: 3.28.1-1
  Candidate: 3.28.1-1
  Version table:
 *** 3.28.1-1 500
        500 http://us.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-boxes 3.28.1-1
ProcVersionSignature: Ubuntu 5.0.0-25.26~18.04.1-generic 5.0.18
Uname: Linux 5.0.0-25-generic x86_64
NonfreeKernelModules: nvidia_modeset nvidia
ApportVersion: 2.20.9-0ubuntu7.7
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Aug 26 19:27:28 2019
InstallationDate: Installed on 2019-07-27 (30 days ago)
InstallationMedia: Ubuntu 18.04.2 LTS "Bionic Beaver" - Release amd64 (20190210)
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gnome-boxes
UpgradeStatus: No upgrade log present (probably fresh install)