[libvirt] [PATCH v2 3/5] conf: Make virNetworkIPDefParseXML a little bit saner

[Jiri Denemark]

On Wed, Dec 14, 2016 at 10:46:20 -0500, Laine Stump wrote:
> On 12/13/2016 08:52 AM, Jiri Denemark wrote:
> > Iterating over all child nodes when we only support one instance of each
> > child is pretty weired. And it would even cause memory leaks if more
> > than one <tftp> element was specified.
> 
> ACK, but could you also look for dhcp[2]/tftp[2] and log an error if found?
> I know there are *lots* of places we ignore extra elements in the XML, but
> in this case there would be a silent behavior change if someone had
> (erroneous) multiple tftp or dhcp elements - previously we would have
> honored the final occurence of each element, but now we honor the first. So
> even though it's their own fault, it would be nice to

Well, if a user provided such a wrong XML, libvirt didn't do what the
user asked for anyway. I don't think implementing a different way of not
doing what they asked for is something we should worry about :-)

That said, adding the check there is trivial, but I'm not sure it's a
good idea since we do not check for extra elements anywhere else.

> (BTW, I've always disliked that some of our XML parsing code iterates
> through the raw nodes like this used to, and some uses XPath to get specific
> nodes. It would be so much easier for newcomers to understand if we picked
> on method and used it consistently...)

Yes, I think we'll eventually rewrite all parsing to use XPath, but it
will take some time.

Jirka