Re: [netmod] Query about usage of local-name() in YANG XPATH expressions
Hi, I added a new issue in github about open vs. closed systems https://github.com/netmod-wg/rfc6087bis/issues/32 Andy On Mon, Mar 28, 2016 at 12:59 PM, William Ivory <wiv...@brocade.com> wrote: > 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:a...@yumaworks.com] > *Sent:* 28 March 2016 20:51 > *To:* William Ivory <wiv...@brocade.com> > *Cc:* netmod@ietf.org > *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 <wiv...@brocade.com> 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 > > > > > ___ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod > <https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ietf.org_mailman_listinfo_netmod=CwMFaQ=IL_XqQWOjubgfqINi2jTzg=GByLeg9jZvOv_AlgBo9uvdDrxizlOR7l_SnTXowyJU8=VZGB2NkaE9--68moPlgZM_ag1CgKvjJqSwwZ2iw1gio=7Ju95XbNKdlg4tPZG9ahSeMHUT_lqGFPtiZxcXevTxw=> > > > ___ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod
Re: [netmod] Query about usage of local-name() in YANG XPATH expressions
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:a...@yumaworks.com] Sent: 28 March 2016 20:51 To: William Ivory <wiv...@brocade.com> Cc: netmod@ietf.org 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 <wiv...@brocade.com<mailto:wiv...@brocade.com>> 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 ___ netmod mailing list netmod@ietf.org<mailto:netmod@ietf.org> https://www.ietf.org/mailman/listinfo/netmod<https://urldefense.proofpoint.com/v2/url?u=https-3A__www.ietf.org_mailman_listinfo_netmod=CwMFaQ=IL_XqQWOjubgfqINi2jTzg=GByLeg9jZvOv_AlgBo9uvdDrxizlOR7l_SnTXowyJU8=VZGB2NkaE9--68moPlgZM_ag1CgKvjJqSwwZ2iw1gio=7Ju95XbNKdlg4tPZG9ahSeMHUT_lqGFPtiZxcXevTxw=> ___ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod
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 Ivorywrote: > 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 > > > ___ > netmod mailing list > netmod@ietf.org > https://www.ietf.org/mailman/listinfo/netmod > > ___ netmod mailing list netmod@ietf.org https://www.ietf.org/mailman/listinfo/netmod