"Larsson, Gustav" <[email protected]> wrote: > (Originally posted to the netconf mailing list in error. My > apologies.) > > Hello, > > When a node defaults to config true and a deviation changes it to > config false, should "deviate add" or "deviate replace" be used? Some > YANG implementations allow either, some allow only "deviate > replace". Perhaps some allow only "deviate add" but we have not yet > seen that. > > Consider these definitions: > > container x { > leaf y { > type string; > } > } > > deviation /x/y { > deviate replace { <-- Should this be add or replace? > config false; > } > } > > Section 7.18.3.2 of RFC 6020 says: > > The argument "add" adds properties to the target node. The > properties to add are identified by substatements to the "deviate" > statement. If a property can only appear once, the property MUST > NOT > exist in the target node.
All nodes in the data tree has a "config" value; if it isn't explicitly specified it is inherited from the parent, and if the top-level node doesn't have an explicit statement it defaults to "true". So in order to change this property, it should be deviated with 'replace'. > The argument "replace" replaces properties of the target node. The > properties to replace are identified by substatements to the > "deviate" statement. The properties to replace MUST exist in the > target node. > > /x/y is config true by default even though config is not explictly > given. Section 7.19.1 of RFC 6020 is not clear about whether config is > considered to exist when defaulted. Don't you think it is clear how the config value is inherited? If "config" is not specified, the default is the same as the parent schema node's "config" value. If the parent node is a "case" node, the value is the same as the "case" node's parent "choice" node. If the top node does not specify a "config" statement, the default is "true". This text doesn't use the words "config property", this could probably be clarified. /martin > > If config is considered to exist, then "deviate replace" is > correct. Otherwise, "deviate add" is correct. Technically, RFC 6020 > allows only one or the other but not both in this case, but perhaps a > robust implementation should accept both. > > YANG file authors need to pick one or the other, so clear guidance > would be helpful. > > Thanks, > Gustav > > _______________________________________________ > netmod mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/netmod > _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
