Re: [netmod] yang-instance-file include-defaults leaf

[Benoit Claise <[e-mail]>]

Thanks Rob for proposing this solution.
It uses the with-defaults-mode typedef (which, in the end, is a good 
thing IMO from a tool point view) and the description makes it clear 
that it applies to instance data file uses cases.

Regards, Benoit

On 9/15/2021 11:56 AM, Rob Wilton (rwilton) wrote:
>
> Balazs,
>
> Would this text be sufficient to alleviate your concerns?
>
> leaf includes-defaults {
>
>    type ncwd:with-defaults-mode;
>
>    default report-all;
>
>    description "
>
>      Indicates how data nodes with default values are
>
>      represented for all data nodes contained in the
>
>      instance-data-set.
>
>      It uses the same definitions as per section 3 of RFC 6243,
>
>      but applied in the context of an instance data file rather
>
>      than a NETCONF request using the <with-defaults>
>
>      parameter.
>
>      For JSON files, the encoding of the 'report-all-tagged'
>
>      option is as defined in section 4.8.9 of RFC 8040.";
>
>    reference “With-defaults Capability for NETCONF, RFC 6243.”
>
> }
>
> I think that having a default value for the leaf is helpful, but I 
> don’t mind if you prefer to set it to trim instead.
>
> Andy, would this also be acceptable to you?
>
> Regards,
> Rob
>
> *From:*Andy Bierman <[e-mail]>
> *Sent:* 14 September 2021 18:09
> *To:* Balázs Lengyel <[e-mail]>
> *Cc:* Rob Wilton (rwilton) <[e-mail]>; NetMod WG 
> <[e-mail]>
> *Subject:* Re: [netmod] yang-instance-file include-defaults leaf
>
> Hi,
>
> I do not have time for a conference on this leaf.
>
> You think this cut-and-paste is good engineering and not confusing to 
> users.
>
> I disagree.
>
> IMO it is less confusing to use the correct typedef and declare in 
> your leaf description-stmt
>
> that the inclusion of defaults is not considered a retrieval, so 6243, 
> sec 3 does not apply.
>
> Andy
>
> On Tue, Sep 14, 2021 at 8:24 AM Balázs Lengyel 
> <[e-mail] <mailto:[e-mail]>> wrote:
>
>     Hello,
>
>     My view is that reusing the data ncwd:with-defaults-mode datatype,
>     might be acceptable, but it is wrong, because:
>
>      1. As opposed to what Andy has wrote the data type does reference
>         "RFC 6243 <https://datatracker.ietf.org/doc/html/rfc6243>;
>         Section 3
>         <https://datatracker.ietf.org/doc/html/rfc6243#section-3>."
>         (See line 58 in the YANG module). Section 3 contains a lot of
>         concepts that are inappropriate for the instance-data draft
>         (server, data retrieval, capabilities)
>      2. The typedef’s description is "Possible modes to */report/*
>         default data." From the 8 listed use-cases only two UC4 and
>         UC5 is about reporting. In UC1,UC2,UC3, UC7,UC8 the
>         instance-data-set is usually prepared by human SW developers
>         which is not reporting. In UC6 we do not know whether this is
>         about reporting, replying, or just sending the data.
>
>     In the instance-data draft we always avoided assumptions about who
>     creates the instance-data and why. There are so many potential
>     use-cases, that they may have very different processes creating
>     and using the data.  The data is just present or absent. The
>     wording in With-default RFC is too specific: “data is reported ...”.
>
>      3. report-all-tagged description contains “XML attribute” which
>         is incorrect if we use JSON encoding. You can have an
>         attribute in JSON, but here specifically an XML attribute is
>         mentioned.
>      4. Rob, you stated  that it is preferred to use the 2119 terms
>         SHALL, SHALL NOT in the enum descriptions (and I also think it
>         is the good solution). So, I reworded the text, that if the
>         data node is covered by the instance-data-set then the enum’s
>         value MUST be adhered to. The ncwd:with-defaults-mode datatype
>         uses wording like “is reported”, “not reported”.
>
>     That said, if this is the cost of getting this document to the
>     IESG, I can accept the data-type. Please decide, so we can move
>     forward.
>     I am willing to have a conference, would you arrange it?
>
>     Regards Balazs
>
>     *From:*Rob Wilton (rwilton) <[e-mail]
>     <mailto:[e-mail]>>
>     *Sent:* 2021. szeptember 13., hétfő 12:05
>     *To:* Andy Bierman <[e-mail]
>     <mailto:[e-mail]>>; Balázs Lengyel
>     <[e-mail] <mailto:[e-mail]>>
>     *Cc:* NetMod WG <[e-mail] <mailto:[e-mail]>>
>     *Subject:* RE: [netmod] yang-instance-file include-defaults leaf
>
>     Hi Andy, Balazs,
>
>     I’m wondering whether it might be helpful to arrange a meeting to
>     get to consensus on this issue (which I believe is important)?
>
>     The concern that I raised in my original AD review was that the
>     data set is allowed to be partial with the RECOMMENDATION that
>     default values are removed from the data set. Hence, I think that
>     those two choices combine to make it impossible for a consumer of
>     an instance data file to know whether a data node has been
>     excluded because it contained the default value vs it has been
>     excluded because it not part of the data set.
>
>     However, I think that Andy is potentially coming from the
>     perspective that if these instance data files represent
>     configuration then understanding how RFC 6243 with-defaults
>     handling applies is important.  To that end,  I quite like Andy’s
>     suggestion of directly reusing the ncwd:with-defaults-mode type,
>     because it guarantees that the definitions are entirely
>     consistent, and I believe that it sufficient to address my concern.
>
>          leaf includes-defaults {
>
>      type ncwd:with-defaults-mode;
>
>          }
>
>     Balazs, is there some way, perhaps with a tweaked description, or
>     assigned default value for the leaf includes-defaults leaf, that
>     this could be made to work for you?
>
>     Thanks,
>
>     Rob
>
>     *From:*Andy Bierman <[e-mail] <mailto:[e-mail]>>
>     *Sent:* 10 September 2021 18:03
>     *To:* Balázs Lengyel <[e-mail]
>     <mailto:[e-mail]>>
>     *Cc:* Rob Wilton (rwilton) <[e-mail]
>     <mailto:[e-mail]>>; NetMod WG <[e-mail]
>     <mailto:[e-mail]>>
>     *Subject:* Re: [netmod] yang-instance-file include-defaults leaf
>
>     On Fri, Sep 10, 2021 at 5:15 AM Balázs Lengyel
>     <[e-mail] <mailto:[e-mail]>>
>     wrote:
>
>         See below as BALAZS4
>
>         *From:*Andy Bierman <[e-mail]
>         <mailto:[e-mail]>>
>         *Sent:* 2021. szeptember 10., péntek 4:57
>         *To:* Balázs Lengyel <[e-mail]
>         <mailto:[e-mail]>>
>         *Cc:* Rob Wilton (rwilton) <[e-mail]
>         <mailto:[e-mail]>>; NetMod WG <[e-mail]
>         <mailto:[e-mail]>>
>         *Subject:* Re: [netmod] yang-instance-file include-defaults leaf
>
>         On Thu, Sep 9, 2021 at 6:19 AM Balázs Lengyel
>         <[e-mail]
>         <mailto:[e-mail]>> wrote:
>
>             Hello Andy,
>
>             See below as BALAZS3.
>
>             *From:*Andy Bierman <[e-mail]
>             <mailto:[e-mail]>>
>             *Sent:* 2021. augusztus 25., szerda 18:29
>             *To:* Balázs Lengyel <[e-mail]
>             <mailto:[e-mail]>>
>             *Cc:* Rob Wilton (rwilton) <[e-mail]
>             <mailto:[e-mail]>>; NetMod WG <[e-mail]
>             <mailto:[e-mail]>>
>             *Subject:* Re: [netmod] yang-instance-file
>             include-defaults leaf
>
>             Hi,
>
>             Here is the latest text. It is inconsistent with RFC 6243,
>             section 3.
>
>             IMO the subsections should be cited instead of the
>             copy-and-change approach.
>
>             BALAZS3: The 6243 sections contain parts about “data
>             retrieval” “capabilities” or “conceptual data nodes set by
>             the server”
>
>             These parts are not relevant for many of the instance data
>             use cases, so I would like to stick with including text here.
>
>         I guess I do not understand why the "with-defaults" leaf or at
>         leaf "with-defaults-mode" typedef
>
>         cannot be used. IMO this is bad practice. Applications that
>         already know how to deal
>
>         with defaults according to RFC 6243 should be supported.
>
>              leaf includes-defaults {
>
>                  type ncwd:with-defaults-mode;
>
>              }
>
>         I do not see any text in this typedef that is server-specific.
>
>         Andy
>
>         BALAZS4:  While I generally agree that duplication is a bad
>         practice, I avoided using ncwd:with-defaults-mode because:
>
>         ·It references RFC 6243
>         <https://datatracker.ietf.org/doc/html/rfc6243>; Section 3
>         <https://datatracker.ietf.org/doc/html/rfc6243#section-3>
>         which is full of inappropriate references (server, data
>         retrieval, capabilities)
>
>         ·The typedef’s description is "Possible modes to report
>         default data." However, in a number of use cases (e.g., UC2
>         Preloading default configuration data, UC7, U8) the data is
>         not reported.
>
>         ·report-all-tagged description contains “XML attribute” which
>         is incorrect if we use JSON encoding
>
>         ·I prefer to use the 2119 term SHALL, SHALL NOT in the enum
>         descriptions.
>
>         Is this acceptable?
>
>     The data type I suggested does not have any references to section 3.
>
>     It does not have any MUST,SHOULD,MAY text at all.
>
>     The JSON encoding in RFC 7951 supports attributes.
>
>     IMO this leaf will cause a lot of confusion for users.
>
>     includes-defaults looks like with-defaults but it isn't.
>
>     It uses the exact same enums as with-defaults, but they mean
>     different things.
>
>     Andy
>
>                leaf includes-defaults {
>
>                      type enumeration {
>
>                        enum report-all {
>
>                          value 1;
>
>                          description
>
>                            "All data nodes SHOULD be included
>             independent of
>
>                              any default values.";
>
>             AB: should follow 6243, 3.1
>
>                        }
>
>                        enum trim {
>
>                          value 2;
>
>                          description
>
>                            "Data nodes that have a default defined and
>             where
>
>                              the actual value is the default value SHOULD
>
>                              NOT be included.";
>
>             AB: should follow 6243, section 3.2
>
>                        }
>
>                        enum explicit {
>
>                          value 3;
>
>                          description
>
>                            "Data nodes that have a default defined and
>             where
>
>                              the actual value is the default value
>             SHOULD NOT be
>
>                              included. However, if the actual value
>             was set by
>
>                              a NETCONF client or other management
>             application
>
>                              by the way of an explicit management
>             operation the
>
>                              data node SHOULD be included.";
>
>             AB: should follow 6243, section 3.3
>
>                        }
>
>                      }
>
>                      description
>
>                        "As instance-data-sets MAY contain incomplete
>             data sets,
>
>                          thus any data node MAY be absent.
>
>                          Providing the instance-data-set intends to
>             contain a
>
>                          full data set, this leaf specifies whether
>             the data set
>
>                          includes data nodes that have a default
>             defined and
>
>                          where the actual value is the same as the
>             default value.
>
>                          Data nodes that have no default values should
>             always
>
>                          be included.
>
>                          Data nodes that have a default value, but the
>             actual
>
>                          value is not equal to the schema defined default
>
>                          should always be included.";
>
>             AB: The last paragraph should be removed or changed. Why
>             are these nodes special?
>
>             Nodes that are actually present and do not contain the
>             YANG default
>
>             are not relevant to this object.
>
>             BALAZS3: OK
>
>                      reference
>
>                        "RFC 6243
>             <https://datatracker.ietf.org/doc/html/rfc6243>:
>             With-defaults Capability for NETCONF";
>
>                    }
>
>             The best way to indicate a representation of a YANG
>             default in the data set is to include
>
>             the "default" attribute in each default node.
>             https://datatracker.ietf.org/doc/html/rfc6243#section-6
>             <https://datatracker.ietf.org/doc/html/rfc6243#section-6>
>
>             This actually works for explicit mode and leaf-lists
>             (unlike the current solution).
>
>             BALAZS3: OK. Added report-all-tagged enum to
>             includes-defaults leaf.
>
>             Here is the current proposed text:
>
>             ------------------------------------------------------------
>
>                 leaf includes-defaults {
>
>             type enumeration {
>
>             enum report-all {
>
>              value 1;
>
>             description
>
>             "All data nodes SHALL be included independent of
>
>             any default values, if the data node
>
>                           is covered by the instance-data-set.";
>
>                     }
>
>             enum report-all-tagged  {
>
>             value 2;
>
>             description
>
>             "All data nodes SHALL be included independent of
>
>             any default values if the data node
>
>                           is covered by the instance-data-set.
>
>             Any nodes considered to be default data SHALL
>
>                     contain a 'default' attribute set to 'true'";
>
>             }
>
>                     enum trim {
>
>             value 3;
>
>             description
>
>             "Data nodes that have a default defined and where
>
>             the actual value is equal to the schema default
>
>                           value SHALL NOT be included.";
>
>                     }
>
>             enum explicit {
>
>             value 4;
>
>             description
>
>             "Data nodes where the actual value is equal to the
>
>                           schema default value SHALL NOT be included.
>
>                           However, if the actual value was set by a
>             NETCONF
>
>                           client or other management application by
>             the way
>
>                           of an explicit management operation, the
>             data node
>
>                           SHALL be included, if the data node is
>             covered by
>
>                           the instance-data-set.";
>
>                     }
>
>                   }
>
>             description
>
>             "An instance-data-set may contain or exclude default
>
>                       data. This leaf indicates whether default data is
>
>                       included.
>
>                       As instance-data-sets MAY contain incomplete data
>
>                       sets: MAY NOT cover all data nodes. A leaf or
>
>                       leaf-list MAY be absent because the
>             instance-data-set
>
>                       does not intend to include the data node
>             independent
>
>                       of default handling.";
>
>             reference
>
>             "RFC 6243: With-defaults Capability for NETCONF
>
>             RFC 8040 :RESTCONF Protocol";
>
>                 }
>
>             ------------------------------------------------------------
>
>             On Tue, Aug 24, 2021 at 1:41 AM Balázs Lengyel
>             <[e-mail]
>             <mailto:[e-mail]>> wrote:
>
>                 Hello Andy,
>
>                 In the -17 I removed the default value for
>                 includes-defaults as you proposed.
>
>                 I am not sure I understand the rest of the comments as
>                 instance-file-format does not use the concept of
>                 “basic-mode”. It has a single leaf to indicate what is
>                 the situation with defaults in the specific
>                 instance-data-set.
>
>                 As this is not a live server request/reply situation
>                 we do not want to specify a basic and additional
>                 modes, we just want to specify the handling used for
>                 this specific instance data set.
>
>                 Regards Balazs
>
>                 *From:*Andy Bierman <[e-mail]
>                 <mailto:[e-mail]>>
>                 *Sent:* 2021. augusztus 23., hétfő 18:58
>                 *To:* Balázs Lengyel <[e-mail]
>                 <mailto:[e-mail]>>
>                 *Cc:* Rob Wilton (rwilton) <[e-mail]
>                 <mailto:[e-mail]>>; NetMod WG
>                 <[e-mail] <mailto:[e-mail]>>
>                 *Subject:* Re: [netmod] yang-instance-file
>                 include-defaults leaf
>
>                 On Mon, Aug 23, 2021 at 5:17 AM Balázs Lengyel
>                 <[e-mail]
>                 <mailto:[e-mail]>> wrote:
>
>                     Hello Rob,
>
>                     I think this won’t fly.
>
>                     In sections 1.2 and 2 we state:
>
>                     /“Instance data files MAY contain partial data sets.”/
>
>                     Which is important for many use-cases.  This means
>                     you cannot say that a default value will or must
>                     be included, as they might be omitted because they
>                     are not part of the partial data set.
>
>                     In a way it is difficult to separate between
>                     leaves that are missing because
>
>                     -They are not part of the partial data-set
>
>                     -They are omitted because they have the default
>                     value and one of the trim or explicit options is used
>
>                     If this becomes important the report-alloptions
>                     shall be used.
>
>                 I thought we already agreed there cannot be a default
>                 or there is no way to
>
>                 represent "no defaults added".
>
>                 Note that "report-all" is not useful if
>                 basic-mode=explicit, since a leaf reporting the YANG
>                 default
>
>                 could be set by the client.  Only report-all-tagged
>                 will clearly identify defaults in this case.
>
>                 Also note that if basic-mode=report-all then there
>                 will be no defaults ever reported.
>
>                 This mode means the server does not consider any node
>                 to be a default and always returns
>
>                 every node (if with-defaults used or not).
>
>                     This is the reason I used the SHOULD word.
>
>                     Regards Balazs
>
>                 Andy
>
>                     *From:*Rob Wilton (rwilton) <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Sent:* 2021. augusztus 23., hétfő 12:27
>                     *To:* Balázs Lengyel <[e-mail]
>                     <mailto:[e-mail]>>; Andy
>                     Bierman <[e-mail]
>                     <mailto:[e-mail]>>; NetMod WG
>                     <[e-mail] <mailto:[e-mail]>>
>                     *Subject:* RE: [netmod] yang-instance-file
>                     include-defaults leaf
>
>                     Hi Balazs, Andy, Netmod,
>
>                     Sorry for the delayed response.  I would still
>                     like to strength the description of the defaults.
>                     E.g., RFC 6243 uses MUSTs rather than SHOULDs.
>
>                     Hence, I have generated some proposed alternative
>                     descriptions, that are somewhat stricter, but also
>                     more generically focussed only on the default values.
>
>                     With these definitions, I think that we could
>                     define the “include-defaults” default value to be
>                     “explicit”, since if the leaf if not included,
>                     then I think that this effectively what the
>                     meaning would be anyway.
>
>                     In particular, I would propose changing the
>                     descriptions as follows:
>
>                     leaf includes-defaults {
>
>                     type enumeration {
>
>                     enum report-all {
>
>                     value 1;
>
>                     description
>
>                     "All data nodes SHOULD be included independent of
>
>                     any default values.";
>
>                     }
>
>                     enum trim {
>
>                     value 2;
>
>                     description
>
>                     "Data nodes that have a default defined and where
>
>                     the actual value is the default value SHOULD
>
>                     NOT be included.";
>
>                     }
>
>                     enum explicit {
>
>                     value 3;
>
>                     description
>
>                     "Data nodes that have a default defined and where
>
>                     the actual value is the default value SHOULD NOT be
>
>                     included. However, if the actual value was set by
>
>                     a NETCONF client or other management application
>
>                     by the way of an explicit management operation the
>
>                     data node SHOULD be included.";
>
>                     }
>
>                     }
>
>                     Proposed:
>
>                     leaf includes-defaults {
>
>                     type enumeration {
>
>                     enum report-all {
>
>                     value 1;
>
>                     description
>
>                     "The instance data set includes all data nodes,
>
>                     including those that contain the schema default.”;
>
>                     }
>
>                     enum trim {
>
>                     value 2;
>
>                     description
>
>                     "The instance data set excludes all data nodes
>
>                     that contain the schema default.";
>
>                     }
>
>                     enum explicit {
>
>                     value 3;
>
>                     description
>
>                     "The instance data set may include some data nodes
>
>                     that match the schema default and may exclude some
>
>                     data nodes that match the schema default.”;
>
>                     }
>
>                     }
>
>                     description
>
>                     "This leaf provides an indication of how default data
>
>                     is presented within an instance data set, modelled on
>
>                     RFC 6243.
>
>                     Interpretation of the use of defaults depends on the
>
>                     context of what the instance data set represents.
>
>                     E.g., if the instance data set represents
>                     configuration,
>
>                     Then include-defaults aligns to the meaning of the
>
>                     default-handling basic modes in RFC 6243.  If the
>
>                     instance data set represents operational data from
>                     the
>
>                                 operational state datastore [RFC
>                     8342], then
>
>                     include-defaults aligns to the definition of that
>
>                     datastore in RFC 8342.”;
>
>                     Would text along these lines work?
>
>                     Thanks,
>
>                     Rob
>
>                     *From:*Balázs Lengyel <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Sent:* 28 July 2021 23:08
>                     *To:* Rob Wilton (rwilton) <[e-mail]
>                     <mailto:[e-mail]>>; Andy Bierman
>                     <[e-mail] <mailto:[e-mail]>>
>                     *Cc:* NetMod WG <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Subject:* RE: [netmod] yang-instance-file
>                     include-defaults leaf
>
>                     Hello Rob,
>
>                     Removing the “default trim;” will address Andy’s
>                     comment.
>
>                     Your /in-use-values/ is very specific to one of
>                     the use-cases: reading/documenting operational
>                     values. It is not useful for the other use-cases.
>                     I think the “documenting operational datastore”
>                     use-case could be handled by indicating the
>                     /includes-defaults=report-all/. Case (i) would
>                     contain the value case (ii) will not.
>
>                     Regards Balazs
>
>                     *From:*Rob Wilton (rwilton) <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Sent:* 2021. július 27., kedd 17:38
>                     *To:* Andy Bierman <[e-mail]
>                     <mailto:[e-mail]>>; Balázs Lengyel
>                     <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Cc:* NetMod WG <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Subject:* RE: [netmod] yang-instance-file
>                     include-defaults leaf
>
>                     Hi Andy, Balazs,
>
>                     So, the reason that I want a flag to indicate
>                     whether default values are in use is because of
>                     this definition of operational in RFC 8342:
>
>                     Requests to retrieve nodes from <operational>
>                     always return the value
>
>                        in use if the node exists, regardless of any
>                     default value specified
>
>                        in the YANG module.  If no value is returned
>                     for a given node, then
>
>                        this implies that the node is not used by the
>                     device.
>
>                     It was written this way because otherwise a
>                     consumer of operational data cannot differentiate
>                     between:
>
>                     (i)This value is not present because it matches
>                     the default value specified in the YANG module, and
>
>                     (ii)This value is not present because the server
>                     has failed to return it for some reason (e.g.,
>                     perhaps the daemon that would have provided this
>                     value is down or not available, or perhaps it is a
>                     bug, or perhaps it is not implemented and is a
>                     missing deviation).
>
>                     So, I think that in some cases, the absence of a
>                     data node does not necessarily mean that the
>                     default value is in effect, and I wanted the
>                     instance-data document to be able to contain and
>                     correctly report this data.
>
>                     I think that this behaviour could be captured by a
>                     single leaf. Another way of articulating this
>                     would be:
>
>                     leaf in-use-values {
>
>                       type boolean;
>
>                     default false;
>
>                     description
>
>                     “Only if set to true, the absence of a value in the
>
>                     instance data for a given data node implies that the
>
>                         node is not used rather than implicitly taking the
>
>                     default value specified by any corresponding
>
>                         ‘default’ statement specified in the YANG
>                     schema.”;
>
>                     }
>
>                     With this, I’m not sure whether we need the
>                     “includes-default” leaf currently specified in the
>                     draft, but if we do, then I would think that leaf
>                     should be entirely optional, i.e., without the
>                     default “trim”.
>
>                     Regards,
>                     Rob
>
>                     *From:*Andy Bierman <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Sent:* 10 July 2021 17:41
>                     *To:* Rob Wilton (rwilton) <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Cc:* NetMod WG <[e-mail]
>                     <mailto:[e-mail]>>; Balázs Lengyel
>                     <[e-mail]
>                     <mailto:[e-mail]>>
>                     *Subject:* Re: [netmod] yang-instance-file
>                     include-defaults leaf
>
>                     On Fri, Jul 9, 2021 at 5:23 AM Rob Wilton
>                     (rwilton) <[e-mail]
>                     <mailto:[e-mail]>> wrote:
>
>                         Andy,
>
>                         Yes, when I suggested this, I was thinking
>                         that a boolean flag might be sufficient. My
>                         point being that automatically filtering out
>                         default values isn’t always the right thing to do.
>
>                     The solution is simple.
>
>                     Get rid of the inappropriate "default trim" statement.
>
>                     If the leaf is present then it identifies the
>                     basic-mode that was used to include defaults.
>
>                     If not then the information is either not known,
>                     not applicable, or defaults were not added.
>
>                     The "default" statement is a bug because there is
>                     no default basic-mode.
>
>                     All of the basic-modes are in use in deployments
>                     and no camp has ever
>
>                     been able to convince the others that theirs is right.
>
>                     Andy
>
>                         E.g., something along these lines:
>
>                         leaf exclude-defaults {
>
>                           type boolean;
>
>                           default true;
>
>                           description
>
>                             “Can be used to reduce the size of the
>                         content data file.
>
>                               When unset or set to true, data nodes
>                         that have a default defined and
>
>                               where the actual value is the default
>                         value are excluded from the content
>
>                               data.
>
>                               When set to false, data nodes with
>                         default value are not filtered, and
>
>                               may appear in the content data.”
>
>                         }
>
>                         Would this satisfy your concern?
>
>                         Regards,
>                         Rob
>
>                         *From:*netmod <[e-mail]
>                         <mailto:[e-mail]>> *On Behalf
>                         Of *Andy Bierman
>                         *Sent:* 08 July 2021 18:16
>                         *To:* NetMod WG <[e-mail]
>                         <mailto:[e-mail]>>
>                         *Subject:* [netmod] yang-instance-file
>                         include-defaults leaf
>
>                         Hi,
>
>                         The module has this object:
>
>                             leaf includes-defaults {
>
>                                type enumeration {
>
>                                  enum report-all {
>
>                                    value 1;
>
>                                    description
>
>                                      "All data nodes SHOULD be
>                         included independent of
>
>                                        any default values.";
>
>                                  }
>
>                                  enum trim {
>
>                                    value 2;
>
>                                    description
>
>                                      "Data nodes that have a default
>                         defined and where
>
>                                        the actual value is the default
>                         value SHOULD
>
>                                        NOT be included.";
>
>                                  }
>
>                                  enum explicit {
>
>                                    value 3;
>
>                                    description
>
>                                      "Data nodes that have a default
>                         defined and where
>
>                                        the actual value is the default
>                         value SHOULD NOT be
>
>                                        included. However, if the
>                         actual value was set by
>
>                                        a NETCONF client or other
>                         management application
>
>                                        by the way of an explicit
>                         management operation the
>
>                                        data node SHOULD be included.";
>
>                                  }
>
>                                }
>
>                                default trim;
>
>                         The draft is extremely server-centric, like
>                         most IETF standards, but this
>
>                         leaf is too server-centric to ignore.
>
>                         Consider the possibility that the source of
>                         the file is NOT a NETCONF server.
>
>                         This data may not be known so the default of
>                         "trim" may not be correct.
>
>                         IMO this leaf is noise because any tool that
>                         knows the schema will also
>
>                         know the YANG defaults.  The solution is
>                         incomplete anyway because
>
>                         the presence of a leaf that has a YANG default
>                         is not enough.
>
>                         The "report-all-tagged" mode must be used to
>                         identify defaults.
>
>                         IMO this leaf should be removed, but at least
>                         add an enum called "unknown".
>
>                         Andy
>
>
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