Draft handle of head reset input in open state

input-output-hk · May 7, 2024 · 7f160a4 · 7f160a4
1 parent 7ea77db
commit 7f160a4
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diff --git a/hydra-node/src/Hydra/API/ClientInput.hs b/hydra-node/src/Hydra/API/ClientInput.hs
@@ -14,6 +14,7 @@ data ClientInput tx
   | Close
   | Contest
   | Fanout
+  | Reset
   deriving stock (Generic)
 
 deriving stock instance IsTx tx => Eq (ClientInput tx)
@@ -35,3 +36,4 @@ instance Arbitrary tx => Arbitrary (ClientInput tx) where
     Close -> []
     Contest -> []
     Fanout -> []
+    Reset -> []
diff --git a/hydra-node/src/Hydra/HeadLogic.hs b/hydra-node/src/Hydra/HeadLogic.hs
@@ -700,6 +700,8 @@ update ::
 update env ledger st ev = case (st, ev) of
   (_, NetworkInput _ (ConnectivityEvent conn)) ->
     onConnectionEvent conn
+  (Open{}, ClientInput Reset) ->
+    newState HeadReset
   (Idle _, ClientInput Init) ->
     onIdleClientInit env
   (Idle _, ChainInput Observation{observedTx = OnInitTx{headId, headSeed, headParameters, participants}, newChainState}) ->
@@ -779,6 +781,24 @@ update env ledger st ev = case (st, ev) of
 -- | Reflect 'StateChanged' events onto the 'HeadState' aggregate.
 aggregate :: IsChainState tx => HeadState tx -> StateChanged tx -> HeadState tx
 aggregate st = \case
+  HeadReset ->
+    case st of
+      Open os@OpenState{coordinatedHeadState} ->
+        Open
+          os
+            { coordinatedHeadState =
+                -- Spec: Tall ← ̂Tall ∪ { (hash(tx), tx) }
+                coordinatedHeadState
+                  { seenSnapshot = LastSeenSnapshot lastSeen
+                  }
+            }
+       where
+        lastSeen = case confirmedSnapshot of
+          InitialSnapshot{} -> 0
+          ConfirmedSnapshot{snapshot = Snapshot{number}} -> number
+
+        CoordinatedHeadState{confirmedSnapshot} = coordinatedHeadState
+      _otherState -> st
   HeadInitialized{parameters = parameters@HeadParameters{parties}, headId, headSeed, chainState} ->
     Initial
       InitialState
@@ -1021,6 +1041,7 @@ recoverChainStateHistory initialChainState =
     ChainRolledBack{chainState} ->
       rollbackHistory (chainStateSlot chainState) history
     TickObserved{} -> history
+    HeadReset -> history
 
 recoverState ::
   (Foldable t, IsChainState tx) =>

diff --git a/hydra-node/src/Hydra/HeadLogic/Outcome.hs b/hydra-node/src/Hydra/HeadLogic/Outcome.hs
@@ -77,6 +77,7 @@ data StateChanged tx
   | HeadFannedOut {chainState :: ChainStateType tx}
   | ChainRolledBack {chainState :: ChainStateType tx}
   | TickObserved {chainSlot :: ChainSlot}
+  | HeadReset
   deriving stock (Generic)
 
 deriving stock instance (IsTx tx, Eq (HeadState tx), Eq (ChainStateType tx)) => Eq (StateChanged tx)
@@ -106,6 +107,7 @@ genStateChanged env =
     , HeadFannedOut <$> arbitrary
     , ChainRolledBack <$> arbitrary
     , TickObserved <$> arbitrary
+    , pure HeadReset
     ]
  where
   Environment{party} = env