Error 3160003: Invalid table iterator

Question

Getting the Error 3160003: Invalid table iterator error while trying to execute:

 cleos push action voting.debug debug '[ 0 ]' -p user@active

I have a simple voting contract (full code) where I'm trying to print candidate by id.

Here is a chunk of code which probably doesn't work:

  /// @abi action
  void debug( uint64_t id ) {
    print("Hello, ", name{getcandidate(id)});
  }

  /// @abi action
  account_name getcandidate( uint64_t id ) const {
    Candidates candidates( _self, _self );
    auto element = candidates.find( id );
    return element->name;
  }

The struct which is stored in multi-index table candidates:

struct candidate {
  uint64_t id;
  account_name name;

  auto primary_key() const { return id; }
};
...
typedef eosio::multi_index<N(candidates), candidate> Candidates;

Appreciate any help and advice. I'm using eos 1.1.0.

Answer 1

If your table doesn't have any elements, then it will throw this error.

Whenever you use the find command, always check afterwards that an element was found:

auto element = candidates.find( id );
if(element != candidates.end())
{
  return element_name;
}