printer json BUGFIX nested union value print

[Ilyesbenhamouda]

Fix an infinite loop in json_print_value() when
resolved type of a union member is also union.

Fixes: 183b911 ("printer json BUGFIX union realtype value print")

[michalvasko]

Please switch the target branch to devel, we do not accept PRs into master. Also, do you have a non-working use-case illustrating the need for this fix? I think you are right but a new test would still be appreciated.

[Ilyesbenhamouda]

Done for the target branch :)

Here is an example illustrating the need of this fix:

• Schema example:

list A {
      key "name";
      description
        "A";

      leaf name {
        type union {
          type uint8;
          type string;
        }
        description
          "List name.";
      }
etc..
}

list B {
      key "name";
      description
        "B";

      leaf name {
        type union {
          type uint16;
          type string;
        }
        description
          "List name.";
      }
etc..
}

leaf C {
  type union {
    type leafref {
      path
        "A/name";
      require-instance false;
    }
    type leafref {
      path
        "B/name";
      require-instance false;
    }
  }
  description
    "C";
}

• Configuration example:
  <C>toto</C>

[michalvasko]

Thanks, test added.