From d5827f62f2cccb25cc5badb58ddb54d09f59721d Mon Sep 17 00:00:00 2001
From: Thomas Athorne <thomas.athorne@trili.tech>
Date: Fri, 20 May 2022 10:11:56 +0100
Subject: [PATCH] Proto: SCORU: add `level` to refutation game type

---
 src/proto_alpha/lib_protocol/alpha_context.mli |  1 +
 .../lib_protocol/sc_rollup_game_repr.ml        | 18 ++++++++++++------
 .../lib_protocol/sc_rollup_game_repr.mli       |  6 ++++++
 3 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/proto_alpha/lib_protocol/alpha_context.mli b/src/proto_alpha/lib_protocol/alpha_context.mli
index 1afc764720de..818a6c8b56c3 100644
--- a/src/proto_alpha/lib_protocol/alpha_context.mli
+++ b/src/proto_alpha/lib_protocol/alpha_context.mli
@@ -2612,6 +2612,7 @@ module Sc_rollup : sig
     type t = {
       turn : player;
       inbox_snapshot : Inbox.t;
+      level : Raw_level.t;
       dissection : (State_hash.t option * Tick.t) list;
     }
 
diff --git a/src/proto_alpha/lib_protocol/sc_rollup_game_repr.ml b/src/proto_alpha/lib_protocol/sc_rollup_game_repr.ml
index a5bcc03d1eb0..2322c868fa95 100644
--- a/src/proto_alpha/lib_protocol/sc_rollup_game_repr.ml
+++ b/src/proto_alpha/lib_protocol/sc_rollup_game_repr.ml
@@ -99,6 +99,7 @@ type player = Alice | Bob
 type t = {
   turn : player;
   inbox_snapshot : Sc_rollup_inbox_repr.t;
+  level : Raw_level_repr.t;
   dissection : (State_hash.t option * Sc_rollup_tick_repr.t) list;
 }
 
@@ -130,13 +131,14 @@ let opponent = function Alice -> Bob | Bob -> Alice
 let encoding =
   let open Data_encoding in
   conv
-    (fun {turn; inbox_snapshot; dissection} ->
-      (turn, inbox_snapshot, dissection))
-    (fun (turn, inbox_snapshot, dissection) ->
-      {turn; inbox_snapshot; dissection})
-    (obj3
+    (fun {turn; inbox_snapshot; level; dissection} ->
+      (turn, inbox_snapshot, level, dissection))
+    (fun (turn, inbox_snapshot, level, dissection) ->
+      {turn; inbox_snapshot; level; dissection})
+    (obj4
        (req "turn" player_encoding)
        (req "inbox_snapshot" Sc_rollup_inbox_repr.encoding)
+       (req "level" Raw_level_repr.encoding)
        (req
           "dissection"
           (list
@@ -159,13 +161,15 @@ let pp_dissection ppf d =
 let pp ppf game =
   Format.fprintf
     ppf
-    "[%a] %a playing; inbox snapshot is %a"
+    "[%a] %a playing; inbox snapshot = %a; level = %a"
     pp_dissection
     game.dissection
     pp_player
     game.turn
     Sc_rollup_inbox_repr.pp
     game.inbox_snapshot
+    Raw_level_repr.pp
+    game.level
 
 module Index = struct
   type t = Staker.t * Staker.t
@@ -220,6 +224,7 @@ let initial inbox ~(parent : Commitment.t) ~(child : Commitment.t) ~refuter
   {
     turn = (if alice_to_play then Alice else Bob);
     inbox_snapshot = inbox;
+    level = child.inbox_level;
     dissection =
       [
         (Some parent.compressed_state, Sc_rollup_tick_repr.initial);
@@ -466,6 +471,7 @@ let play game refutation =
              {
                turn = opponent game.turn;
                inbox_snapshot = game.inbox_snapshot;
+               level = game.level;
                dissection = states;
              })
     | Proof proof ->
diff --git a/src/proto_alpha/lib_protocol/sc_rollup_game_repr.mli b/src/proto_alpha/lib_protocol/sc_rollup_game_repr.mli
index 04c4a6705bd0..d50970a8e67f 100644
--- a/src/proto_alpha/lib_protocol/sc_rollup_game_repr.mli
+++ b/src/proto_alpha/lib_protocol/sc_rollup_game_repr.mli
@@ -182,6 +182,11 @@ type player = Alice | Bob
       otherwise they would have a 'moving target' because the actual
       inbox may be updated continuously.
 
+    - [level], the inbox level of the commitment the game is refuting.
+      This is only used when checking [Blocked_step] proofs---the proof
+      will show that the next message available in [inbox_snapshot] is
+      at [level], so shouldn't be included in this commitment.
+
     - [dissection], a list of states with tick counts. The current
       player will specify, in the next move, a tick count that
       indicates the last of these states that she agrees with.
@@ -195,6 +200,7 @@ type player = Alice | Bob
 type t = {
   turn : player;
   inbox_snapshot : Sc_rollup_inbox_repr.t;
+  level : Raw_level_repr.t;
   dissection : (State_hash.t option * Sc_rollup_tick_repr.t) list;
 }
 
-- 
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