package tezos-protocol-014-PtKathma

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package tezos-protocol-014-PtKathma
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module Commitment_hash = Sc_rollup_commitment_repr.Hash
type point = {
  1. commitment : Sc_rollup_commitment_repr.t;
  2. hash : Commitment_hash.t;
}
type conflict_point = point * point

game_move ctxt rollup player opponent refutation is_opening_move handles the storage-side logic for when one of the players makes a move in the game. It initializes the game if is_opening_move is true. Otherwise, it checks the game already exists. Then it checks that player is the player whose turn it is; if so, it applies refutation using the play function.

If the result is a new game, this is stored and the timeout level is updated.

If the result is an outcome, this will be returned.

May fail with:

  • Sc_rollup_does_not_exist if rollup does not exist
  • Sc_rollup_no_game if is_opening_move is false but the game does not exist
  • Sc_rollup_game_already_started if is_opening_move is true but the game already exists
  • Sc_rollup_no_conflict if player is staked on an ancestor of the commitment staked on by opponent, or vice versa
  • Sc_rollup_not_staked if one of the player or opponent is not actually staked
  • Sc_rollup_staker_in_game if one of the player or opponent is already playing a game
  • Sc_rollup_wrong_turn if a player is trying to move out of turn

The is_opening_move argument is included here to make sure that an operation intended to start a refutation game is never mistaken for an operation to play the second move of the game---this may otherwise happen due to non-deterministic ordering of L1 operations. With the is_opening_move parameter, the worst case is that the operation simply fails. Without it, the operation would be mistaken for an invalid move in the game and the staker would lose their stake!

timeout ctxt rollup stakers checks that the timeout has elapsed and if this function returns a game outcome that punishes whichever of stakers is supposed to have played a move.

The timeout period is currently defined in timeout_period_in_blocks. This should become a protocol constant soon.

May fail with:

  • Sc_rollup_no_game if the game does not in fact exist
  • Sc_rollup_timeout_level_not_reached if the player still has time in which to play

Note: this function takes the two stakers as a pair rather than separate arguments. This reflects the fact that for this function the two players are symmetric. This function will normalize the order of the players if necessary to get a valid game index, so the argument stakers doesn't have to be in normal form.

apply_outcome ctxt rollup outcome takes an outcome produced by timeout or game_move and performs the necessary end-of-game cleanup: remove the game itself from the store and punish the losing player by removing their stake.

It also translates the 'internal' type to represent the end of the game, outcome, into the status type that makes sense to the outside world.

This is mostly just calling remove_staker, so it can fail with the same errors as that. However, if it is called on an outcome generated by game_move or timeout it should not fail.

Note: this function takes the two stakers as a pair rather than separate arguments. This reflects the fact that for this function the two players are symmetric. This function will normalize the order of the players if necessary to get a valid game index, so the argument stakers doesn't have to be in normal form.

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