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

[RFC Errata System <[e-mail]>]

The following errata report has been submitted for RFC8040,
"RESTCONF Protocol".

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid6271

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Type: Technical
Reported by: Kent Watsen <[e-mail]>

Section: 4.5

Original Text
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   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
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   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.

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".
  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...

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RFC8040 (draft-ietf-netconf-restconf-18)
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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