stop checking for irrelevant unsigned wraparound in Electra deposit codepath (#6683)

beacon_chain/el/eth1_chain.nim

@@ -330,7 +330,19 @@ proc getBlockProposalData*(chain: var Eth1Chain,
   if pendingDepositsCount > 0:
     if hasLatestDeposits:
       let
-        totalDepositsInNewBlock = min(MAX_DEPOSITS, pendingDepositsCount)
+        totalDepositsInNewBlock =
+          withState(state):
+            when consensusFork >= ConsensusFork.Electra:
+              # https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.8/specs/electra/validator.md#deposits
+              let eth1_deposit_index_limit = min(
+                forkyState.data.eth1_data.deposit_count,
+                forkyState.data.deposit_requests_start_index)
+              if forkyState.data.eth1_deposit_index < eth1_deposit_index_limit:
+                min(MAX_DEPOSITS, pendingDepositsCount)
+              else:
+                0
+            else:
+              min(MAX_DEPOSITS, pendingDepositsCount)
         postStateDepositIdx = stateDepositIdx + pendingDepositsCount
       var
         deposits = newSeqOfCap[DepositData](totalDepositsInNewBlock)

beacon_chain/spec/state_transition_block.nim

@@ -685,7 +685,7 @@ type
 
 # https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.8/specs/phase0/beacon-chain.md#operations
 # https://github.com/ethereum/consensus-specs/blob/v1.4.0-beta.5/specs/capella/beacon-chain.md#modified-process_operations
-# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.3/specs/electra/beacon-chain.md#operations
+# https://github.com/ethereum/consensus-specs/blob/v1.5.0-alpha.8/specs/electra/beacon-chain.md#modified-process_operations
 proc process_operations(
     cfg: RuntimeConfig, state: var ForkyBeaconState,
     body: SomeForkyBeaconBlockBody, base_reward_per_increment: Gwei,
@@ -698,17 +698,24 @@ proc process_operations(
       eth1_deposit_index_limit =
         min(state.eth1_data.deposit_count, state.deposit_requests_start_index)
       req_deposits =
+        # Otherwise wraps because unsigned; Python spec semantics would result in
+        # negative difference, which would be impossible for len(...) to match.
         if state.eth1_deposit_index < eth1_deposit_index_limit:
+          if eth1_deposit_index_limit < state.eth1_deposit_index:
+            return err("eth1_deposit_index_limit < state.eth1_deposit_index")
           min(
             MAX_DEPOSITS, eth1_deposit_index_limit - state.eth1_deposit_index)
         else:
           0
   else:
+    # Otherwise wraps because unsigned; Python spec semantics would result in
+    # negative difference, which would be impossible for len(...) to match.
+    if state.eth1_data.deposit_count < state.eth1_deposit_index:
+      return err("state.eth1_data.deposit_count < state.eth1_deposit_index")
     let req_deposits = min(
       MAX_DEPOSITS, state.eth1_data.deposit_count - state.eth1_deposit_index)
 
-  if state.eth1_data.deposit_count < state.eth1_deposit_index or
+  if body.deposits.lenu64 != req_deposits:
-      body.deposits.lenu64 != req_deposits:
     return err("incorrect number of deposits")
 
   var operations_rewards: BlockRewards

tests/consensus_spec/test_fixture_fork_choice.nim

@@ -79,10 +79,6 @@ proc initialLoad(
       path/"anchor_state.ssz_snappy",
       StateType.kind)
 
-    blck = parseTest(
-      path/"anchor_block.ssz_snappy",
-      SSZ, BlockType)
-
   ChainDAGRef.preInit(db, forkedState[])
 
   let