Re: [netconf] [Technical Errata Reported] RFC8040 (6271)

On Tue, Sep 1, 2020 at 11:27 PM Martin Björklund <mbj+ietf@4668.se> wrote:

> Hi,
>
> RFC Errata System <rfc-editor@rfc-editor.org> wrote:
> > The following errata report has been submitted for RFC8040,
> > "RESTCONF Protocol".
> >
> > --------------------------------------
> > You may review the report below and at:
> > https://www.rfc-editor.org/errata/eid6271
> >
> > --------------------------------------
> > Type: Technical
> > Reported by: Kent Watsen <kent+ietf@watsen.net>
> >
> > Section: 4.5
> >
> > Original Text
> > -------------
> >    The "insert" (Section 4.8.5) and "point" (Section 4.8.6) query
> >    parameters MUST be supported by the PUT method for data resources.
> >    These parameters are only allowed if the list or leaf-list is
> >    "ordered-by user".
> >
> >
> > Corrected Text
> > --------------
> >    The "insert" (Section 4.8.5) and "point" (Section 4.8.6) query
> >    parameters MUST be supported by the PUT method for data resources.
> >    These parameters are only allowed if the target resource is a
> >    non-existent entry of an "ordered-by user" list or leaf-list.
>
> I don't think this is correct.  The new text makes it impossible to
> move an existing ordered-by user list entry, which should be
> possible.  4.8.6 says:
>
>    The "point" query parameter is used to specify the insertion point
>    for a data resource that is being created or moved within an
>    "ordered-by user" list or leaf-list.
>
> See below.
>
>
> > Notes
> > -----
> > First, Section 3.5 (Data Resource) says that "list" and "leaf-leaf"
> > are not a data resources:
> >
> >   A data resource represents a YANG data node that is a descendant node
> >   of a datastore resource. Each YANG-defined data node can be uniquely
> >   targeted by the request-line of an HTTP method. Containers, leafs,
> >   leaf-list entries, list entries, anydata nodes, and anyxml nodes are
> >   data resources.
> >
> > Second, these query parameters only make sense when targeting a
> > non-existent entry.  If the entry does not exist, then PUT is being
> > used like a POST: to create and place an item in an ordered list.
> > However, if the entry exists, then PUT is being used to both replace
> > the contents and (presumably) re-place the order in the list; but this
> > doesn't make sense because:
> >
> >   1) "insert" defaults to "last".
> >   2) there is no "insert" value to indicate "keep existing placement".
>
> I think this is the real problem.  It should be (and the intention was):
>
>   1.  if "insert" isn't present and a new entry is created, the new
>       entry will be appended to the end of the list.
>
>   2.  if "insert" isn't present a an entry is modified (PUT), the
>       entry keeps its place in the list.
>
>

Agreed.  So the errata only applies to the  "insert" query parameter.

> /martin
>

Andy

>
>
>
>
> >   3) having to concoct valid "insert" and "point" values is hard.
> >
> > Thus indiscriminate PUTs would move entries to the end, which can't be
> > desired...
> >
> > Instructions:
> > -------------
> > This erratum is currently posted as "Reported". If necessary, please
> > use "Reply All" to discuss whether it should be verified or
> > rejected. When a decision is reached, the verifying party
> > can log in to change the status and edit the report, if necessary.
> >
> > --------------------------------------
> > RFC8040 (draft-ietf-netconf-restconf-18)
> > --------------------------------------
> > Title               : RESTCONF Protocol
> > Publication Date    : January 2017
> > Author(s)           : A. Bierman, M. Bjorklund, K. Watsen
> > Category            : PROPOSED STANDARD
> > Source              : Network Configuration
> > Area                : Operations and Management
> > Stream              : IETF
> > Verifying Party     : IESG
> >
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>