Re: [yang-doctors] ?= [netconf] Require-instance problem [was: RE: =?utf-8?q? WGLC: draft-ietf-netconf-notification-capabilities-11]

[Michal Vaško <[e-mail]>]

Hi Balazs,
just to explain libyang behavior, if you look at (pattern <https://tools.ietf.org/html/rfc7950#section-9.4.5> ) definition, there is explicitly mentioned that it can appear in derived types. There is no such wording for (require-instance <https://tools.ietf.org/html/rfc7950#section-9.9.3> ), it mentions only "instance-identifier" and "leafref" types.

Also, libyang does not allow loading invalid schemas so even if you only import it, it will fail.

Regards,
Michal

On Friday, March 13, 2020 09:55 CET, Balázs Lengyel <balazs.lengyel=[e-mail]> wrote: 
 
> Hello Mahesh,
> 
> Even if there is some problem with ietf-subscribed-notification how does that effect the validity of instance data for ietf-system-capabilities or ietf-notification-capabilities ? I only import a type and a feature from Yangpush (which imports subscribed notification). These seem nothing to do with require-instance.
> 
>  
> 
> Aside from my draft:
> 
> I do not understand some of libyangs statements:  
> 
> “as it turned out (ref <https://tools.ietf.org/html/rfc7950#section-9.9.3> ), you cannot put require-instance into a derived type”. 
> 
> Checking ref I did not find why you cannot put require instance into a typedef.
> 
>  
> 
> By the way I have bigger issues with YangValidator. When I load ietf-system-capabilities@2020-03-08 into it I get 
> 
>  
> 
> RecursionError at /yangvalidator/validator
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> maximum recursion depth exceeded
> 
> 
> Request Method:
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> POST
> 
> 
> Request URL:
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> http://www.yangvalidator.com/yangvalidator/validator
> 
> 
> Django Version:
> 
> 3.0.4
> 
> 
> Exception Type:
> 
> RecursionError
> 
> 
> Exception Value:
> 
> maximum recursion depth exceeded
> 
> 
> Exception Location:
> 
> /home/yang/yangvalidator/lib/python3.6/site-packages/pyang-2.1.1-py3.6.egg/pyang/statements.py in newf, line 42
> 
> 
> Python Executable:
> 
> /usr/sbin/uwsgi
> 
> 
> Python Version:
> 
> 3.6.10
> 
> 
> Python Path:
> 
> ['/home/yang/yangvalidator/lib/python3.6/site-packages/pyang-2.1.1-py3.6.egg/pyang/transforms',
> 
>  
> 
> Regards Balazs
> 
>  
> 
> From: Mahesh Jethanandani <[e-mail]> 
> Sent: 2020. március 12., csütörtök 22:28
> To: Balázs Lengyel <[e-mail]>
> Cc: Kent Watsen <[e-mail]>; [e-mail]; [e-mail]
> Subject: Re: [netconf] WGLC: draft-ietf-netconf-notification-capabilities-11
> 
>  
> 
> [Adding yang-doctors]
> 
>  
> 
> Hi Balazs,
> 
>  
> 
>  
> 
> On Mar 10, 2020, at 2:06 AM, Balázs Lengyel <[e-mail] <mailto:[e-mail]> > wrote:
> 
>  
> 
> Finally, have all the examples in the appendix been validated?
> 
> BALAZS: Yes, they have been loaded into a live Confd server.
> 
>  
> 
> I bring this up because I ran into issues when validating the https-notif model using ietf-subscribed-notification module, something that you also import. Here is what I see when I try to use yanglint to validate your example. In this case, I named your example as examples-notification-capabilities-1.xml.
> 
>  
> 
> bash-3.2$ yanglint -s -i -t auto -p /Volumes/External/git/iana/yang-parameters/ [e-mail] <mailto:[e-mail]>  [e-mail] <mailto:[e-mail]>  examples-notification-capabilities-1.xml 
> 
> err : Invalid keyword "require-instance".
> 
> err : Module "ietf-subscribed-notifications" parsing failed.
> 
> err : Importing "ietf-subscribed-notifications" module into "ietf-yang-push" failed.
> 
> err : Module "ietf-yang-push" parsing failed.
> 
> err : Importing "ietf-yang-push" module into "ietf-notification-capabilities" failed.
> 
> err : Module "ietf-notification-capabilities" parsing failed.
> 
>  
> 
> At first I thought the issue was with yanglint, because just like you I used confd and it did not complain. But folks over at libyang tell me that this was discussed as part of their issue  #881 <https://protect2.fireeye.com/v1/url?k=a6420c80-fa9605e6-a6424c1b-8610d8a762ca-d6cddc5edf1151a7&q=1&e=3cd8e8af-8aea-4f96-939b-8e1e455eac74&u=https%3A%2F%2Fgithub.com%2FCESNET%2Flibyang%2Fissues%2F881>  and the conclusion was that you cannot put require-instance in a derived type based on this <https://tools.ietf.org/html/rfc7950#section-9.9.3>  text.
> 
>  
> 
> Who is correct in their assertion, libyang or confd/RFC8639?
> 
>  
> 
> In case anyone is wondering which ietf-subsciribed-notifications module is being imported, here it is:
> 
>  
> 
> bash-3.2$ ls .../iana/yang-parameters/[e-mail] <mailto:iana/yang-parameters/[e-mail]> 
> 
>  
> 
> Cheers.
> 
>  
> 
> BTW, even if I comment out the ‘require-instance’ statement, yanglint complains about other issues with ietf-subscribed-notifications, which I will bring up in a separate thread.
> 
>  
> 
> Mahesh Jethanandani
> 
> [e-mail] <mailto:[e-mail]> 
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>  
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>