RFC 8040, "RESTCONF Protocol", January 2017

Note: This RFC has been updated by RFC 8527

Errata ID: 6215
Status: Reported
Type: Technical
Publication Format(s) : TEXT
Reported By: Kent Watsen
Date Reported: 2020-06-25

Section 4.3 says:

   If a retrieval request for a data resource representing a YANG
   leaf-list or list object identifies more than one instance and XML
   encoding is used in the response, then an error response containing a
   "400 Bad Request" status-line MUST be returned by the server.  The
   error-tag value "invalid-value" is used in this case.  Note that a
   non-configuration list is not required to define any keys.  In this
   case, the retrieval of a single list instance is not possible.

Notes:

This whole paragraph should be removed because, according to Section 3.5 (Data Resource), the "list" and "leaf-leaf" themselves 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.

No GET, PUT, POST, DELETE, or PATCH example in the RFC illustrates an operation on a "list" or "leaf-list" directly (i.e., without a key, which would then represent an element of the list or leaf-list).

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