virt-manager keeps store-paths as part of virtual machines configuration

[bjornfor]

This leads to issues like this, where the virtual machine cannot start, after having set up a virtual machine some time ago and then garbage collecting:

Error starting domain: Cannot check QEMU binary /nix/store/z5c2xzk9x0pj6x511w0w4gy9xl5wljxy-qemu-1.5.2-x86-only/bin/qemu-kvm: No such file or directory

The store-path reference is located in here:

$ sudo grep -rn qemu-kvm /etc/libvirt/
/etc/libvirt/qemu/ubuntu.xml:28:    <emulator>/nix/store/z5c2xzk9x0pj6x511w0w4gy9xl5wljxy-qemu-1.5.2-x86-only/bin/qemu-kvm</emulator>

I can also see the store path in virt-manager in Details->Overview->Hypervisor Details, but it is just shown as read-only info, it cannot be changed from there.

It is quite user unfriendly to have virt-manager break virtual machines like this, we should fix it.

[bjornfor]

Fixed in f52f9bf.

[ZoomRmc]

Just have ran into the same problem on 18.09.2360
The machine was suspended and didn't want to wake up, on rebooting got the same error with stored qemu-kvm path, had to manually edit xml.
Have I detected a possible regression?