说我有这个
container c {
leaf l1;
leaf l2 (default 'abcd');
}
我这样做（restconf）：
DELETE / c / l2
服务器中的预期行为是什么？ 是吗
发出删除后，GET的预期结果是什么
GET /c
c {
l1 : 100 // for ex
l2 : 'abcd'
}
答案 0 :(得分：2)
The default value of a leaf is the value that the server uses if the leaf does not exist in the data tree. The usage of the default value depends on the leaf's closest ancestor node in the schema tree that is not a non-presence container (see Section 7.5.1): o If no such ancestor exists in the schema tree, the default value MUST be used. o Otherwise, if this ancestor is a case node, the default value MUST be used if any node from the case exists in the data tree or the case node is the choice's default case, and if no nodes from any other case exist in the data tree. o Otherwise, the default value MUST be used if the ancestor node exists in the data tree. In these cases, the default value is said to be in use. Note that if the leaf or any of its ancestors has a "when" condition or "if-feature" expression that evaluates to "false", then the default value is not in use. When the default value is in use, the server MUST operationally behave as if the leaf was present in the data tree with the default value as its value. If a leaf has a "default" statement, the leaf's default value is the value of the "default" statement. Otherwise, if the leaf's type has a default value and the leaf is not mandatory, then the leaf's default value is the type's default value. In all other cases, the leaf does not have a default value.
在您的情况下c是一个非在线容器，因此上面的第一个项目符号开始。这意味着如果您从数据树中删除相应的叶子，您的默认值将被使用（是的，您可以删除它）。因此，服务器必须在操作上表现得就像叶子存在一样，并且该叶子必须具有指定的默认值。
使用哪种协议进行操作并不重要。
对于RESTCONF和GET，行为在Section 3.5.4：
中描述RESTCONF requires that a server report its default handling mode (see Section 9.1.2 for details). If the optional "with-defaults" query parameter is supported by the server, a client may use it to control retrieval of default values (see Section 4.8.9 for details). If a leaf or leaf-list is missing from the configuration and there is a YANG-defined default for that data resource, then the server MUST use the YANG-defined default as the configured value. If the target of a GET method is a data node that represents a leaf or leaf-list that has a default value, and the leaf or leaf-list has not been instantiated yet, the server MUST return the default value(s) that are in use by the server. In this case, the server MUST ignore its basic-mode, described in Section 4.8.9, and return the default value. If the target of a GET method is a data node that represents a container or list that has any child resources with default values, for the child resources that have not been given value yet, the server MAY return the default values that are in use by the server, in accordance with its reported default handing mode and query parameters passed by the client.
因此，您的GET示例可能正确，也可能不正确，具体取决于哪种默认处理模式有效，如上面的最后一段所示。