Hi Andy,

Thanks.  So if we have a tightly controlled set of YANG files, and restrict 
usage to a specific use case where we have a set of nodes across multiple 
modules with the same name, we should be fine.

William

From: Andy Bierman [mailto:[email protected]]
Sent: 28 March 2016 20:51
To: William Ivory <[email protected]>
Cc: [email protected]
Subject: Re: [netmod] Query about usage of local-name() in YANG XPATH 
expressions

Hi,

This was raised as a concern by Lada (see netmod WG email arourd July 2014)

The issue is that the expression breaks module containment and will match
depending on what other YANG modules are known to the YANG compiler.


Andy



On Sat, Mar 26, 2016 at 3:08 AM, William Ivory 
<[email protected]<mailto:[email protected]>> wrote:
Hi,

From RFC 6087 (YANG Usage Guidelines), section 5.6.2, the following is noted 
about the use of the XPATH local-name() function:

   The 'local-name' function SHOULD NOT be used to reference local names
   outside of the YANG module defining the must or when expression
   containing the 'local-name' function.  Example of a local-name
   function that should not be used:

      /*[local-name()='foo']

However, no explanation is given as to why this is a bad idea.  We have a 
specific use case where local-name() would appear to allow us to massively 
simplify some rather cumbersome must expressions, but I wanted to check I’m not 
missing some ‘gotcha’ here.  Is it simply that relying on a common node name 
across multiple modules is generally a bad design as it ties the modules 
together, or is there more to it?  If so, then in our case this is a reasonable 
restriction.

Thanks,

William


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