update to ethereum/consensus-specs#750. add deposit top up test

spec_pythonizer/sanity_check.py

@@ -347,6 +347,52 @@ def test_deposit_in_block(state):
     return state, [block], test_state
 
 
+@timeit
+def test_deposit_top_up(state):
+    test_state = deepcopy(state)
+    test_deposit_data_leaves = deepcopy(all_deposit_data_leaves)
+    withdrawal_credentials = b'\x42' * 32
+    deposit_timestamp = 1
+    proof_of_possession = b'\x44' * 96
+    amount = MAX_DEPOSIT_AMOUNT // 4
+    validator_index = 0
+
+    merkle_index = len(test_deposit_data_leaves)
+    deposit_data = DepositData(
+        amount=amount,
+        timestamp=deposit_timestamp,
+        deposit_input=DepositInput(
+            pubkey=test_state.validator_registry[validator_index].pubkey,
+            withdrawal_credentials=withdrawal_credentials,
+            proof_of_possession=proof_of_possession,
+        ),
+    )
+    item = hash(deposit_data.serialize())
+    test_deposit_data_leaves.append(item)
+    tree = calc_merkle_tree_from_leaves(tuple(test_deposit_data_leaves))
+    root = get_merkle_root((tuple(test_deposit_data_leaves)))
+    proof = list(get_merkle_proof(tree, item_index=merkle_index))
+    assert verify_merkle_branch(item, proof, DEPOSIT_CONTRACT_TREE_DEPTH, merkle_index, root)
+
+    deposit = Deposit(
+        proof=list(proof),
+        index=merkle_index,
+        deposit_data=deposit_data,
+    )
+
+    test_state.latest_eth1_data.deposit_root = root
+    block = construct_empty_block_for_next_slot(test_state)
+    block.body.deposits.append(deposit)
+
+    pre_balance = test_state.validator_balances[validator_index]
+    state_transition(test_state, block)
+    assert len(test_state.validator_registry) == len(state.validator_registry)
+    assert len(test_state.validator_balances) == len(state.validator_balances)
+    assert test_state.validator_balances[validator_index] == pre_balance + amount
+
+    return state, [block], test_state
+
+
 @timeit
 def test_attestation(state):
     test_state = deepcopy(state)
@@ -543,6 +589,8 @@ def sanity_tests():
     print("Passed attestation test\n")
     test_cases.append(test_deposit_in_block(genesis_state))
     print("Passed deposit test\n")
+    test_cases.append(test_deposit_top_up(genesis_state))
+    print("Passed deposit top up test\n")
     test_cases.append(test_voluntary_exit(genesis_state))
     print("Passed voluntary exit test\n")
     test_cases.append(test_transfer(genesis_state))

spec_pythonizer/spec.md

@@ -1288,7 +1288,7 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
     serialized_deposit_data = serialize(deposit.deposit_data)
     # Deposits must be processed in order
     assert deposit.index == state.deposit_index
-    
+
     # Verify the Merkle branch
     merkle_branch_is_valid = verify_merkle_branch(
         leaf=hash(serialized_deposit_data),
@@ -1298,34 +1298,33 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
         root=state.latest_eth1_data.deposit_root,
     )
     assert merkle_branch_is_valid
-        
+
     # Increment the next deposit index we are expecting. Note that this
     # needs to be done here because while the deposit contract will never
     # create an invalid Merkle branch, it may admit an invalid deposit
     # object, and we need to be able to skip over it
     state.deposit_index += 1
-
-    # Verify the proof of possession
-    proof_is_valid = bls_verify(
-        pubkey=deposit_input.pubkey,
-        message_hash=signed_root(deposit_input),
-        signature=deposit_input.proof_of_possession,
-        domain=get_domain(
-            state.fork,
-            get_current_epoch(state),
-            DOMAIN_DEPOSIT,
-        )
-    )
-
-    if not proof_is_valid:
-        return
 
     validator_pubkeys = [v.pubkey for v in state.validator_registry]
     pubkey = deposit_input.pubkey
     amount = deposit.deposit_data.amount
     withdrawal_credentials = deposit_input.withdrawal_credentials
 
     if pubkey not in validator_pubkeys:
+        # Verify the proof of possession
+        proof_is_valid = bls_verify(
+            pubkey=deposit_input.pubkey,
+            message_hash=signed_root(deposit_input),
+            signature=deposit_input.proof_of_possession,
+            domain=get_domain(
+                state.fork,
+                get_current_epoch(state),
+                DOMAIN_DEPOSIT,
+            )
+        )
+        if not proof_is_valid:
+            return
+
         # Add new validator
         validator = Validator(
             pubkey=pubkey,
@@ -1342,10 +1341,7 @@ def process_deposit(state: BeaconState, deposit: Deposit) -> None:
         state.validator_balances.append(amount)
     else:
         # Increase balance by deposit amount
-        index = validator_pubkeys.index(pubkey)
-        assert state.validator_registry[index].withdrawal_credentials == withdrawal_credentials
-
-        state.validator_balances[index] += amount
+        state.validator_balances[validator_pubkeys.index(pubkey)] += amount
 ```
 
 ### Routines for updating validator status