[libvirt] [PATCH v2 14/21] conf: Shorten names in virDomainChrSerialTarget enumeration

[Andrea Bolognani]

On Thu, 2017-11-23 at 16:54 +0100, Pavel Hrdina wrote:
> On Tue, Nov 21, 2017 at 05:42:24PM +0100, Andrea Bolognani wrote:
> > Now that the target type is no longer formatted on the QEMU command
> > line, we don't need the values to match the QEMU device names any
> > longer, so we can shorten the names and reduce redundancy by dropping
> > the -serial suffix: this also has the nice side-effect that target
> > type and address type will now match.
> > 
> > We still need to parse the old names, and format them when preparing
> > a migratable XML, to preserve backwards compatibility.
> 
> This would be probably nice to rename, but I'm afraid that we cannot
> do that.  Even though you've made the effort to translate the old
> name into new name if management application creates the XML using
> the old name, the issue here is that it will no longer understand
> what the new name means until the management application is updated.
> Therefore this change is not backward compatible.

Is that so? virt-manager at least doesn't seem to have a problem
with the change.

Any application that's been coded sensibly will deal with the new
values in a graceful manner, eg. displaying "unknown model" or
something along the line rather than failing. Moreover, any
application that can't deal nicely with the change will certainly
have a problem with the new values that we're introducing for
aarch64, ppc64 and s390, so it will have to be fixed regardless.

-- 
Andrea Bolognani / Red Hat / Virtualization