[netmod] hi Martin, one issue about RFC7950 The "deviate" Statement, please help to confirm

"Zhengguangying (Walker)" <zhengguangying@huawei.com> Fri, 12 January 2018 04:00 UTC

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From: "Zhengguangying (Walker)" <zhengguangying@huawei.com>
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CC: "netmod@ietf.org" <netmod@ietf.org>, "Qudan (Beijing-NOS)" <qudan.qudan@huawei.com>
Thread-Topic: hi Martin, one issue about RFC7950 The "deviate" Statement, please help to confirm
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Date: Fri, 12 Jan 2018 04:00:35 +0000
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Subject: [netmod] hi Martin, one issue about RFC7950 The "deviate" Statement, please help to confirm
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Hi Martin,

When we define YANG model's deviation file, we find one scenario was nor supported but we have one problem depend on it.

Our scenario:
In ACl YANG module, there have two leafs:
acl/aclGroups/aclGroup/aclRuleBas4s/ aclRuleBas4/vrfName
acl/aclGroups/aclGroup/aclRuleBas4s/ aclRuleBas4/vrfAny

And the acl/aclGroups/aclGroup/aclRuleBas4s/ aclRuleBas4/vrfName  have one Constraints:  when "not (../vrfAny = 'true')"

In some product domain, the "vrfAny" does not supported, some they deviate the leaf "vrfAny". From the sematic view, the Constraints of vrfName  when "not (../vrfAny = 'true')" should be deviated as "delete" too.

But, in RFC7950  The "deviate" Statement ,  "when " is not the  Substatement of deviate, we can not deviate the when statement, and the problem coming, some industry netconf tools compile fail because "../vrfAny" does not exist.

And there have some other scenario about "when" deviate, So, I think whether the YANG language should add "when" as the Substatement of deviate?

What's your opinion?

Thanks & regards

Walker(guangying zheng)