Re: [yang-doctors] XPath question

[Andy Bierman <[e-mail]>]

Hi,

This is the key line:

7.9 <https://datatracker.ietf.org/doc/html/rfc7950#section-7.9>.  The
"choice" Statement

   The "choice" statement defines a set of alternatives, only one of
   which may be present in any one data tree.  The argument is an
   identifier, followed by a block of substatements that holds detailed
   choice information.  The identifier is used to identify the choice
   node in the schema tree.  A choice node does not exist in the data
   tree.

   A choice consists of a number of branches, each defined with a "case"
   substatement.  Each branch contains a number of child nodes. * The
   nodes from at most one of the choice's branches exist at the same
   time.*


The term 'node': Does it mean 'schema node' or 'data node'?

Andy


On Mon, Jun 6, 2022 at 2:42 PM Andy Bierman <[e-mail]> wrote:

> Hi,
>
> RFC 7950 does not say whether unselected case-stmts are visible in XPath.
> The bbf-qos-enhanced-scheduling module has a default leaf in 1 case
> and a nested node with a must-stmt in a sibling case that references it.
>
> The issue is whether the XPath context includes the default leaf.
> Case 'queue' and 'child-schedular-queues' are siblings.
> I suspect our code is wrong and the defaults from all cases are visible
> to XPath evaluation.
>
>
>           case queue {
>             description
>               "The children are a list of queues.";
>             leaf contains-queues {
>               type boolean;
>               *default "true";*
>               description
>                 "Indicates the scheduler contains queues.";
>             }
>             uses bbf-qos-tm:queues;
>           }
>           case child-scheduler-queues {
>             if-feature "child-scheduler-queue-references";
>             container child-scheduler-queues {
>               description
>                 "Configuration to reference one or more queues within
>                  one or more child schedulers.";
>               list child-scheduler {
>
>                  // ....
>
>                 container queues {
>
>
> * must "../../../../bbf-qos-sched:scheduler-node"                     +
> "[bbf-qos-sched:name=current()/../name]/"                     +
> "bbf-qos-sched:contains-queues = 'true'" *{
>                     error-message
>                       "The referenced scheduler must contain queues.";
>                     description
>                       "The referenced scheduler must contain queues
>                        in order for queues to be referenced.";
>                   }
>
>
>
> Andy
>
>