get table array values not being returned

[brianjohnson5972]

Specific example is tic_tac_toe tutorial, "get table" returns:

{
"rows": [{
"challenger": "player2",
"host": "player1",
"turn": "player2",
"winner": "none",
"board": []
}
],
"more": false
}

even though board is a uint8_t[9] and has values

[brianjohnson5972]

@wanderingbort
I think the issue is that in the abi the type is defined as "uint8_t[]" which maps to a vector for pack/unpack, but in tic_tack_toe.hpp the parameter is:
uint8_t board[9];
Which will NOT be mapped to operator<< with vector, so the packing/unpacking don't match.

I think it is calling "DataStream& operator << ( DataStream& ds, const std::array<T,N>& v )" which is more efficient for packing/unpacking in contracts, but there is nothing on the abi that could handle this (since no size is stored in the packed format and we don't have anything in the abi that indicates a fixed size array).

The easiest solution to this is to change the implementation of "DataStream& operator << ( DataStream& ds, const std::array<T,N>& v )" to match vector, which is not as efficient, but not terribly. Harder solution is extending the abi to include "yyyy[#]" where # indicates the fixed size of the array and passes that size along with the pack/unpack to indicate size to read/write.

[brianjohnson5972]

Handling this by implementing operator<< for std::array and adding one for "T (&v)[N}" and using a similar implementation to std::vector so that there is a size for abi serializer to use to size the vector that it will allocate to handle all of these types.

[andriantolie]

Played the tic_tac_toe contract and can verify for each step the board is printed properly by cleos get table command