Deviation on augment node is not supported properly.

[corrollFang]

Deviation is not supported properly if it targets on an augment node on libyang-0.14.75, there may be 2 blew problems.

1. There is an error during lys_set_disabled(), error info is as below:

netopeer2-server[9357]: libyang error: Schema node not found.
netopeer2-server[9357]: libyang error: Internal error (/libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:4090).

-------------Code location: -------------

static void
lys_switch_deviation(struct lys_deviation *dev, const struct lys_module *module, struct unres_schema *unres)
{
....
                    if (reapply) {
                        /* augment is supposed to be applied, so fix pointers in target and the status of the original node */
                        parent->flags |= LYS_NOTAPPLIED; /* allow apply_aug() */
                        apply_aug((struct lys_node_augment *)parent, unres);
                    }
                } else if (parent && (parent->nodetype == LYS_USES)) {
                    /* uses child */
                    lys_node_addchild(parent, NULL, dev->orig_node);
                } else {
                    /* non-augment, non-toplevel */
                    parent_path = strndup(dev->target_name, strrchr(dev->target_name, '/') - dev->target_name);
                    ret = resolve_schema_nodeid(parent_path, NULL, module, &set, 0, 1);
                    free(parent_path);
                    if (ret == -1) {//-------Returns error, because the target_node is defined in augment module, it has already been removed, so the target is not found.
                        LOGINT;
                        ly_set_free(set);
                        return;
                    }
                    target = set->set.s[0];
                    ly_set_free(set);

                    lys_node_addchild(target, NULL, dev->orig_node);
                }
...
}

2. The process crashed because of null pointer during lys_parse_path(), the coredump stack is as below:

warning: Source file is more recent than executable, I assume the issued is caused by 1st item.
4207        lys_node_module(dev->orig_node)->deviated = 1; /* main module */
(gdb) p dev->orig_node
$1 = (struct lys_node *) 0x0
(gdb) bt
#0  0xf449d5a3 in apply_dev (unres=<optimized out>, module=0xece6f4a0, dev=0xece699f8)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:4207
#1  lys_sub_module_apply_devs_augs (module=0xece6f4a0)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:4264
#2  0xf443a706 in lys_set_enabled (module=module@entry=0xece6f438)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/context.c:1208
#3  0xf4458501 in lyp_ctx_check_module (module=module@entry=0xece6ab68)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/parser.c:3705
#4  0xf4488b7d in yyparse (scanner=0xece6f380, param=param@entry=0xf3b7d160)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/parser_yang_bis.c:3708
#5  0xf44913fa in yang_parse_mem (module=module@entry=0xece6ab68, submodule=submodule@entry=0x0, unres=0xece67bc0, 
    data=data@entry=0xf3333000 "module deviation-base{\r\n\r\n    namespace \"http://deviation-base\";\r\n    prefix \"base\";\r\n    revision \"2018-03-05\"{\r\n        description\r\n", ' ' <repeats 12 times>, "\"Initial revision.\";\r\n    }\r\n\r\n    container", size_data=size_data@entry=0, node=node@entry=0xf3b7d1dc)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/parser_yang.c:2528
#6  0xf4495b5b in yang_read_module (ctx=ctx@entry=0xece5c2c8, 
    data=data@entry=0xf3333000 "module deviation-base{\r\n\r\n    namespace \"http://deviation-base\";\r\n    prefix \"base\";\r\n    revision \"2018-03-05\"{\r\n        description\r\n", ' ' <repeats 12 times>, "\"Initial revision.\";\r\n    }\r\n\r\n    container", size=size@entry=0, revision=revision@entry=0x0, implement=implement@entry=1)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/parser_yang.c:2607
#7  0xf449f8ff in lys_parse_mem_ (ctx=ctx@entry=0xece5c2c8, 
    data=0xf3333000 "module deviation-base{\r\n\r\n    namespace \"http://deviation-base\";\r\n    prefix \"base\";\r\n    revision \"2018-03-05\"{\r\n        description\r\n", ' ' <repeats 12 times>, "\"Initial revision.\";\r\n    }\r\n\r\n    container", format=format@entry=LYS_IN_YANG, revision=revision@entry=0x0, internal=internal@entry=1, 
    implement=implement@entry=1)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:955
#8  0xf449fa85 in lys_parse_fd_ (ctx=ctx@entry=0xece5c2c8, fd=fd@entry=109, format=format@entry=LYS_IN_YANG, 
    revision=revision@entry=0x0, implement=implement@entry=1)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:1115
#9  0xf449fbfe in lys_parse_fd (ctx=ctx@entry=0xece5c2c8, fd=fd@entry=109, format=format@entry=LYS_IN_YANG)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:1089
#10 0xf449fc64 in lys_parse_path (ctx=0xece5c2c8, path=0x8064bc2 "deviation-base.yang", format=LYS_IN_YANG)
    at libyang-fbfc9c7774212c09b048418da38b0883084eb317/src/tree_schema.c:1046

------------------YANG models-----------------------------
-----------module deviation-base--------

module deviation-base{

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

    container c1
    {
        leaf flag
        {
            type boolean;
            default true;
        }
    }
}

---------module deviation-augment-----------

module deviation-augment {

    namespace "http://deviation-augment";
    prefix "deviation-augment";

    import deviation-base {
        prefix "base";
    }

    revision "2018-03-05"{
        description
            "Initial revision.";
    }
    
    augment /base:c1 {
        container aug-c1 {
            leaf aug-node {
              type string;
              description
               "Test deviation on augment node.";
            }
            leaf aug-dev {
              type string;
              description
               "Marked as not-supported in deviation.";
            }
        }
    }
}

-------------module test-deviation--------------

module test-deviation {

    namespace "http://test-deviation";
    prefix "test-deviation";

    import deviation-base {
        prefix "base";
    }
    import deviation-augment {
        prefix "aug";
    }

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

    deviation /base:c1/aug:aug-c1/aug:aug-dev {
        deviate not-supported;
    }
}

-----------------Test code--------------------

    //Test deviation on augment
    const struct lys_module* lModule_deviation_base = lys_parse_path(lLyCtxt_tmp, "deviation-base.yang", LYS_IN_YANG);
    const struct lys_module* lModule_dev_augment = lys_parse_path(lLyCtxt_tmp, "deviation-augment.yang", LYS_IN_YANG);
    const struct lys_module* lModule_deviation = lys_parse_path(lLyCtxt_tmp, "test-deviation.yang", LYS_IN_YANG);

    //There are similar code in "dm_release_tmp_ly_ctx()" in sysrepo
    uint32 lIndex = ly_ctx_internal_modules_count(lLyCtxt_tmp);
    const struct lys_module* lModule = ly_ctx_get_module_iter(lLyCtxt_tmp, &lIndex);
    while(lModule)
    {
        int lResult = lys_set_disabled(lModule); //print error for "test-deviation.yang"
        lModule = ly_ctx_get_module_iter(lLyCtxt_tmp, &lIndex);
    }

    //It may be triggered by sr_get_schema()
    lModule_deviation_base = lys_parse_path(lLyCtxt_tmp, "deviation-base.yang", LYS_IN_YANG);//Crashed

[michalvasko]

Hi,
should be working now, a fairly simple fix was enough.

Regards,
Michal

[corrollFang]

Hi,
After update your change, it works well now, thanks a lot.
Best regards.