Container node is added into Libyang data tree during parsing JSON file even if when status is false.

[corrollFang]

----------base.yang--------------

module base{
    namespace "http://test-when/base";
    prefix "base";
    container c1
    {
        leaf flag
        {
            type boolean;
        }
    }
}

----------augment-when.yang-----------

module augment-when {
    namespace "http://test-when/augment-when";
    prefix "augment-when";
    import base {
        prefix "base";
    }
    augment "/base:c1" 
    {
        when "flag = 'true'";
        container aug-1
        {
            leaf xxx
            {
                type uint32;
            }
        }
    }
}

---JSON files---

{"base:c1":{"flag":false}}

After calling lyd_parse_fd(tmp_ctx->ctx, fd, LYD_JSON, LYD_OPT_TRUSTED | LYD_OPT_CONFIG), the returned data tree nodes are as below:

  <c1 xmlns="http://test-when/base">
    <flag>false</flag>
    <augment-when xmlns="http://test-when/augment-when"/>
  </c1>`

The container "augment-when" is added during lyd_wd_add_subtree() and will cause validation failed. I think it's not a good behavior, so i suggest to evaluate when expressions during adding default nodes.

[michalvasko]

Hi,
I believe this is a duplicate of #433 but I will merge it to master so that it is fixed everywhere. Please, try it again.

Regards,
Michal

[corrollFang]

Hi Michal,

Thanks for your response, but i think the 2 issues are caused by different reasons.
#443 is caused by if-feature on augment/grouping, but #452 is caused by "when" state.
So could you help to have a double check, thanks.

Best regards
Corroll

[michalvasko]

Hi Corroll,
did you try it again because I have tried it and that is why I replied what I did, it worked. The issues are caused by different conditions but they are both checked by one function which was not properly called previously.

Regards,
Michal

[corrollFang]

Hi Michal,
I checked it in libyang-0.14.72(508504c), it still doesn't work well, There should not be "aug-when" node.
--------------------YANG models-----------------------------------
-------base-test-when.yang-------
module base-test-when{

namespace "http://test-when/base";
prefix "base";
revision "2018-03-05"{
    description
        "Initial revision.";
}

container c1
{
    leaf flag
    {
        type boolean;
    }
}

}
------augment-when.yang--------
module augment-when{

namespace "http://test-when/augment-when";
prefix "augment-when";

import base-test-when {
    prefix "base";
}


revision "2018-03-05"{
    description
        "Initial revision.";
}

augment "/base:c1" 
{
    when "flag = 'true'";
    container aug-when
    {
        leaf xxx
        {
            type uint32;
        }
    }
}

}
-----------------------JSON data file----------------------------------
{"base-test-when:c1":{"flag":false}}

--------------------------------My application code-------------------------------

struct ly_ctx* lLyCtxt_tmp = ly_ctx_new(NULL, 0);
const struct lys_module* lModule_base = lys_parse_path(lLyCtxt_tmp, "base-test-when.yang", LYS_IN_YANG);
const struct lys_module* lModule_augment = lys_parse_path(lLyCtxt_tmp, "augment-when.yang", LYS_IN_YANG);

struct lyd_node* lRootNode = lyd_parse_path(lLyCtxt_tmp,"data.json",LYD_JSON, LYD_OPT_TRUSTED | LYD_OPT_CONFIG);
if(lRootNode)
{
    FILE* lDataFile_Xml = fopen("data.xml", "w");
    int lRetCode = lyd_print_file(lDataFile_Xml, lRootNode, LYD_XML, LYP_WITHSIBLINGS | LYP_WD_ALL | LYP_KEEPEMPTYCONT);
    fclose(lDataFile_Xml);
}

ly_ctx_destroy(lLyCtxt_tmp, NULL);

--------Result is saved into data.xml after run this code, the content is as below:
<c1 xmlns="http://test-when/base"> <flag>false</flag> <aug-when xmlns="http://test-when/augment-when"/> </c1>

[michalvasko]

Hi,
you are right, the problem was still there but caused by another issue, you found a really specific use-case. Should work now.

Regards,
Michal

[corrollFang]

Hi Michal,
I updated your change and checked it again with the same YANG&C++ code, but there is a coredump issue caused by invalid pointer, I suggest you initialize the variable as "NULL" and check if it's NULL before use it.

The coredump stack is as below.
(gdb) p when
$1 = (struct lys_when *) 0x7c
(gdb) bt
#0 0xf442571d in resolve_unres_data (unres=unres@entry=0xeca69dd0, root=root@entry=0xf3b57220,
options=options@entry=8193)
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/resolve.c:7949
#1 0xf4483e17 in lyd_defaults_add_unres (root=root@entry=0xf3b57220, options=options@entry=8193, ctx=,
ctx@entry=0xeae37c18, data_tree=data_tree@entry=0x0, act_notif=0x0, unres=unres@entry=0xeca69dd0)
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/tree_data.c:6634
#2 0xf4450b4d in lyd_parse_json (ctx=ctx@entry=0xeae37c18,
data=data@entry=0xf3356000 <error: Cannot access memory at address 0xf3356000>, options=options@entry=8193,
rpc_act=rpc_act@entry=0x0, data_tree=data_tree@entry=0x0)
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/parser_json.c:1464
#3 0xf447aed8 in lyd_parse_ (data_tree=0x0, options=8193, format=LYD_JSON,
data=0xf3356000 <error: Cannot access memory at address 0xf3356000>, rpc_act=0x0, ctx=0xeae37c18)
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/tree_data.c:437
#4 lyd_parse_data_ (ctx=ctx@entry=0xeae37c18,
data=data@entry=0xf3356000 <error: Cannot access memory at address 0xf3356000>, format=format@entry=LYD_JSON,
options=options@entry=8193, ap=, ap@entry=0xf3b57320 "\374"m\367<I\006\b\030\016\344\352")
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/tree_data.c:499
#5 0xf447b0ea in lyd_parse_fd_ (ctx=0xeae37c18, fd=, format=LYD_JSON, options=8193,
ap=0xf3b57320 "\374"m\367<I\006\b\030\016\344\352")
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/tree_data.c:536
#6 0xf447b211 in lyd_parse_path (ctx=0xeae37c18, path=0x8064a41 "data.json", format=LYD_JSON, options=8193)
at libyang-508504cfc25b9cf84e5587247c9d740550def094/src/tree_data.c:575

[michalvasko]

Hi,
I hope it will finally work, I should have properly tested it...

Regards,
Michal

[corrollFang]

Hi,
After updating your change, it works well now, thanks a lot.

Best regards.