[libvirt] [PATCH] Clarify behavior or virDomainDetachDevice

[Daniel P. Berrange]

On Fri, Feb 20, 2015 at 01:16:24PM +0100, Michal Privoznik wrote:
> On 20.02.2015 12:39, Ján Tomko wrote:
> > Doucment that not all attributes are used for matching.
> > 
> > https://bugzilla.redhat.com/show_bug.cgi?id=872028
> > ---
> >  src/libvirt-domain.c | 5 +++++
> >  tools/virsh.pod      | 4 +++-
> >  2 files changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
> > index 492e90a..a95c096 100644
> > --- a/src/libvirt-domain.c
> > +++ b/src/libvirt-domain.c
> > @@ -8341,6 +8341,11 @@ virDomainDetachDevice(virDomainPtr domain, const char *xml)
> >   * into S4 state (also known as hibernation) unless you also modify the
> >   * persistent domain definition.
> >   *
> > + * Note that not all attributes from the XML definition are checked.
> > + * For example, if the mac address and the pci address specified in the XML
> > + * match an existing interface, but source and interface type do not,
> > + * the existing interface will be detached.
> > + *
> 
> I don't think we want to advertise this. Users are required to pass full
> device XML. If we use only a part of that information to find the
> device, it's our internal implementation. Not a green light for users to
> pass minimized XMLs.
> Same applies for (partly) inconsistent XMLs (inconsistent to domain
> XML). If we now teach users it's okay to pass XML that differs to its
> domain counterpart, we are stuck with it forever. I'd await plenty of
> bug reports that we broke somebody's flow just because he was passing
> altered XML and we suddenly needed to change the set of attributes that
> are checked.
> 
> NACK, sorry.

Agreed, this docs change will limit our ability to change our impl
later if we need to.

Regards,
Daniel
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