Hi, On Friday, May 18, 2018 12:16 CEST, Martin Bjorklund <[email protected]> wrote: > Hi, > > "Bogaert, Bart (Nokia - BE/Antwerp)" <[email protected]> wrote: > > Hi, > > > > We have a question on YANG module compilation. Assume the following > > model: > > > > module test-feat-compile { > > yang-version 1.1; > > namespace "http://www.example.com/test-feat-compile";; > > prefix "tfc"; > > > > identity failure-reason { > > description > > "The reason a failure occurred."; > > } > > > > identity no-failure { > > description > > "No failure has occurred."; > > } > > > > identity general-error { > > base failure-reason; > > description > > "A general error occurred."; > > } > > > > container failure { > > description > > "Objects associated with a failure."; > > > > leaf failure-reason { > > type identityref { > > base failure-reason; > > } > > description > > "The reason the failure occurred."; > > } > > > > leaf failure-string { > > when "../failure-reason != 'no-failure'" { > > description > > "Only valid when there is a failure."; > > } > > type string; > > description > > "A text string indicating the reason for the failure when > > either no defined reason exists or additional information > > is available beyond the definition of the reason."; > > } > > } > > } > > > > Looking at the when clause there is something obviously wrong (at > > least this is how I see it): > > > > * The leaf 'failure-reason' is of type identityref with 'failure-reason' > > as base > > * Identity 'no-failure' does not have 'failure-reason' as base (see it > > as having been forgotten) > > Question is: shouldn't this be reported at compile time? Pyang > > doesn't and the other compiler we use doesn't report this either. > > > > Even when 'no-failure' is modified into some arbitrary string it is > > still accepted while this arbitrary string is not defined anywhere as > > identity. > > > > And when it comes to the correct syntax, RFC 7950 states (section > > 9.1.3) that identities in must and when statements should be prefixed > > (so tfc:no-failure in this case). Also this "violation" passes. > > > > So: what can we expect to be checked at compile time in this case? > > Now you can only detect these anomalies when using a system supporting > > the modules and detect that things do not work as intended. It would > > be better to have these erroneous constructions being detected at > > compile time. If there is something in the RFC that allows the > > compiler to behave as it does now it would be good to know. > > Strictly speaking, the "when" expressions are not erroneous; they are > proper XPath expressions that happen to always return "false". > > A good compiler could detect this and produce a warning, but it would > be incorrect to flag this as an error.
Exactly and you can try using yanglint(1) from libyang [1], which prints both problems you mentioned as warnings. Kind regards, Michal Vasko [1] https://github.com/cesnet/libyang _______________________________________________ netmod mailing list [email protected] https://www.ietf.org/mailman/listinfo/netmod
