From fea2b712f093cc4d7fd42f0fda68d6bceb2169fa Mon Sep 17 00:00:00 2001
From: Jacek Sieka <jacek@status.im>
Date: Wed, 16 Dec 2020 15:36:02 +0100
Subject: [PATCH] cache not needed to validate exits (#2188)

---
 beacon_chain/exit_pool.nim                   | 15 +++------------
 beacon_chain/spec/state_transition_block.nim | 14 ++++++--------
 2 files changed, 9 insertions(+), 20 deletions(-)

diff --git a/beacon_chain/exit_pool.nim b/beacon_chain/exit_pool.nim
index ec9da1aee..fa6071362 100644
--- a/beacon_chain/exit_pool.nim
+++ b/beacon_chain/exit_pool.nim
@@ -164,12 +164,9 @@ proc validateAttesterSlashing*(
 
   # [REJECT] All of the conditions within process_attester_slashing pass
   # validation.
-  var cache =
-   getStateCache(pool.chainDag.head,
-     pool.chainDag.headState.data.data.slot.compute_epoch_at_slot)
   let attester_slashing_validity =
     check_attester_slashing(
-      pool.chainDag.headState.data.data, attester_slashing, {}, cache)
+      pool.chainDag.headState.data.data, attester_slashing, {})
   if attester_slashing_validity.isErr:
     return err((ValidationResult.Reject, attester_slashing_validity.error))
 
@@ -192,12 +189,9 @@ proc validateProposerSlashing*(
       "validateProposerSlashing: proposer-slashed index already proposer-slashed")))
 
   # [REJECT] All of the conditions within process_proposer_slashing pass validation.
-  var cache =
-   getStateCache(pool.chainDag.head,
-     pool.chainDag.headState.data.data.slot.compute_epoch_at_slot)
   let proposer_slashing_validity =
     check_proposer_slashing(
-      pool.chainDag.headState.data.data, proposer_slashing, {}, cache)
+      pool.chainDag.headState.data.data, proposer_slashing, {})
   if proposer_slashing_validity.isErr:
     return err((ValidationResult.Reject, proposer_slashing_validity.error))
 
@@ -225,12 +219,9 @@ proc validateVoluntaryExit*(
 
   # [REJECT] All of the conditions within process_voluntary_exit pass
   # validation.
-  var cache =
-   getStateCache(pool.chainDag.head,
-     pool.chainDag.headState.data.data.slot.compute_epoch_at_slot)
   let voluntary_exit_validity =
     check_voluntary_exit(
-      pool.chainDag.headState.data.data, signed_voluntary_exit, {}, cache)
+      pool.chainDag.headState.data.data, signed_voluntary_exit, {})
   if voluntary_exit_validity.isErr:
     return err((ValidationResult.Reject, voluntary_exit_validity.error))
 
diff --git a/beacon_chain/spec/state_transition_block.nim b/beacon_chain/spec/state_transition_block.nim
index 28288fa54..972484f2d 100644
--- a/beacon_chain/spec/state_transition_block.nim
+++ b/beacon_chain/spec/state_transition_block.nim
@@ -125,7 +125,7 @@ func is_slashable_validator(validator: Validator, epoch: Epoch): bool =
 # https://github.com/ethereum/eth2.0-specs/blob/v1.0.0/specs/phase0/beacon-chain.md#proposer-slashings
 proc check_proposer_slashing*(
     state: var BeaconState, proposer_slashing: ProposerSlashing,
-    flags: UpdateFlags, cache: var StateCache):
+    flags: UpdateFlags):
     Result[void, cstring] {.nbench.} =
 
   let
@@ -169,7 +169,7 @@ proc process_proposer_slashing*(
     state: var BeaconState, proposer_slashing: ProposerSlashing,
     flags: UpdateFlags, cache: var StateCache):
     Result[void, cstring] {.nbench.} =
-  ? check_proposer_slashing(state, proposer_slashing, flags, cache)
+  ? check_proposer_slashing(state, proposer_slashing, flags)
   slash_validator(
     state,
     proposer_slashing.signed_header_1.message.proposer_index.ValidatorIndex,
@@ -192,8 +192,7 @@ func is_slashable_attestation_data*(
 proc check_attester_slashing*(
        state: var BeaconState,
        attester_slashing: AttesterSlashing,
-       flags: UpdateFlags,
-       cache: var StateCache
+       flags: UpdateFlags
      ): Result[seq[ValidatorIndex], cstring] {.nbench.} =
   let
     attestation_1 = attester_slashing.attestation_1
@@ -230,7 +229,7 @@ proc process_attester_slashing*(
        cache: var StateCache
      ): Result[void, cstring] {.nbench.} =
   let attester_slashing_validity =
-    check_attester_slashing(state, attester_slashing, flags, cache)
+    check_attester_slashing(state, attester_slashing, flags)
 
   if attester_slashing_validity.isErr:
     return err(attester_slashing_validity.error)
@@ -244,8 +243,7 @@ proc process_attester_slashing*(
 proc check_voluntary_exit*(
     state: var BeaconState,
     signed_voluntary_exit: SignedVoluntaryExit,
-    flags: UpdateFlags,
-    cache: var StateCache): Result[void, cstring] {.nbench.} =
+    flags: UpdateFlags): Result[void, cstring] {.nbench.} =
 
   let voluntary_exit = signed_voluntary_exit.message
 
@@ -299,7 +297,7 @@ proc process_voluntary_exit*(
     signed_voluntary_exit: SignedVoluntaryExit,
     flags: UpdateFlags,
     cache: var StateCache): Result[void, cstring] {.nbench.} =
-  ? check_voluntary_exit(state, signed_voluntary_exit, flags, cache)
+  ? check_voluntary_exit(state, signed_voluntary_exit, flags)
   initiate_validator_exit(
     state, signed_voluntary_exit.message.validator_index.ValidatorIndex, cache)
   ok()