async def receive_block(
        self,
        block_record: HeaderBlockRecord,
        pre_validation_result: Optional[PreValidationResult] = None,
        trusted: bool = False,
        fork_point_with_peak: Optional[uint32] = None,
    ) -> Tuple[ReceiveBlockResult, Optional[Err], Optional[uint32]]:
        """
        Adds a new block into the blockchain, if it's valid and connected to the current
        blockchain, regardless of whether it is the child of a head, or another block.
        Returns a header if block is added to head. Returns an error if the block is
        invalid. Also returns the fork height, in the case of a new peak.
        """
        block = block_record.header
        genesis: bool = block.height == 0

        if self.contains_sub_block(block.header_hash):
            return ReceiveBlockResult.ALREADY_HAVE_BLOCK, None, None

        if not self.contains_sub_block(block.prev_header_hash) and not genesis:
            return (
                ReceiveBlockResult.DISCONNECTED_BLOCK,
                Err.INVALID_PREV_BLOCK_HASH,
                None,
            )

        if block.height == 0:
            prev_sb: Optional[SubBlockRecord] = None
        else:
            prev_sb = self.sub_block_record(block.prev_header_hash)
        sub_slot_iters, difficulty = get_sub_slot_iters_and_difficulty(
            self.constants, block, prev_sb, self)

        if trusted is False and pre_validation_result is None:
            required_iters, error = validate_finished_header_block(
                self.constants, self, block, False, difficulty, sub_slot_iters)
        elif trusted:
            unfinished_header_block = UnfinishedHeaderBlock(
                block.finished_sub_slots,
                block.reward_chain_sub_block.get_unfinished(),
                block.challenge_chain_sp_proof,
                block.reward_chain_sp_proof,
                block.foliage_sub_block,
                block.foliage_block,
                block.transactions_filter,
            )

            required_iters, val_error = validate_unfinished_header_block(
                self.constants, self, unfinished_header_block, False,
                difficulty, sub_slot_iters, False, True)
            error = ValidationError(
                Err(val_error)) if val_error is not None else None
        else:
            assert pre_validation_result is not None
            required_iters = pre_validation_result.required_iters
            error = (ValidationError(Err(pre_validation_result.error))
                     if pre_validation_result.error is not None else None)

        if error is not None:
            return ReceiveBlockResult.INVALID_BLOCK, error.code, None
        assert required_iters is not None

        sub_block = block_to_sub_block_record(
            self.constants,
            self,
            required_iters,
            None,
            block,
        )

        # Always add the block to the database
        await self.block_store.add_block_record(block_record, sub_block)
        self.add_sub_block(sub_block)
        self.clean_sub_block_record(sub_block.height -
                                    self.constants.SUB_BLOCKS_CACHE_SIZE)

        fork_height: Optional[uint32] = await self._reconsider_peak(
            sub_block, genesis, fork_point_with_peak)
        if fork_height is not None:
            self.log.info(
                f"💰 Updated wallet peak to sub height {sub_block.height}, weight {sub_block.weight}, "
            )
            return ReceiveBlockResult.NEW_PEAK, None, fork_height
        else:
            return ReceiveBlockResult.ADDED_AS_ORPHAN, None, None
Example #2
0
    async def add_spendbundle(
        self,
        new_spend: SpendBundle,
        cost_result: CostResult,
        spend_name: bytes32,
        validate_signature=True,
    ) -> Tuple[Optional[uint64], MempoolInclusionStatus, Optional[Err]]:
        """
        Tries to add spendbundle to either self.mempools or to_pool if it's specified.
        Returns true if it's added in any of pools, Returns error if it fails.
        """
        start_time = time.time()
        if self.peak is None:
            return None, MempoolInclusionStatus.FAILED, Err.MEMPOOL_NOT_INITIALIZED

        npc_list = cost_result.npc_list
        cost = cost_result.cost

        log.debug(f"Cost: {cost}")

        if cost > self.constants.MAX_BLOCK_COST_CLVM:
            return None, MempoolInclusionStatus.FAILED, Err.BLOCK_COST_EXCEEDS_MAX

        if cost_result.error is not None:
            return None, MempoolInclusionStatus.FAILED, Err(cost_result.error)
        # build removal list
        removal_names: List[bytes32] = new_spend.removal_names()

        additions = additions_for_npc(npc_list)

        additions_dict: Dict[bytes32, Coin] = {}
        for add in additions:
            additions_dict[add.name()] = add

        addition_amount = uint64(0)
        # Check additions for max coin amount
        for coin in additions:
            if coin.amount > self.constants.MAX_COIN_AMOUNT:
                return (
                    None,
                    MempoolInclusionStatus.FAILED,
                    Err.COIN_AMOUNT_EXCEEDS_MAXIMUM,
                )
            addition_amount = uint64(addition_amount + coin.amount)
        # Check for duplicate outputs
        addition_counter = collections.Counter(_.name() for _ in additions)
        for k, v in addition_counter.items():
            if v > 1:
                return None, MempoolInclusionStatus.FAILED, Err.DUPLICATE_OUTPUT
        # Check for duplicate inputs
        removal_counter = collections.Counter(name for name in removal_names)
        for k, v in removal_counter.items():
            if v > 1:
                return None, MempoolInclusionStatus.FAILED, Err.DOUBLE_SPEND
        # Skip if already added
        if spend_name in self.mempool.spends:
            return uint64(cost), MempoolInclusionStatus.SUCCESS, None

        removal_record_dict: Dict[bytes32, CoinRecord] = {}
        removal_coin_dict: Dict[bytes32, Coin] = {}
        unknown_unspent_error: bool = False
        removal_amount = uint64(0)
        for name in removal_names:
            removal_record = await self.coin_store.get_coin_record(name)
            if removal_record is None and name not in additions_dict:
                unknown_unspent_error = True
                break
            elif name in additions_dict:
                removal_coin = additions_dict[name]
                # TODO(straya): what timestamp to use here?
                removal_record = CoinRecord(
                    removal_coin,
                    uint32(self.peak.height + 1),  # In mempool, so will be included in next height
                    uint32(0),
                    False,
                    False,
                    uint64(int(time.time())),
                )

            assert removal_record is not None
            removal_amount = uint64(removal_amount + removal_record.coin.amount)
            removal_record_dict[name] = removal_record
            removal_coin_dict[name] = removal_record.coin
        if unknown_unspent_error:
            return None, MempoolInclusionStatus.FAILED, Err.UNKNOWN_UNSPENT

        if addition_amount > removal_amount:
            print(addition_amount, removal_amount)
            return None, MempoolInclusionStatus.FAILED, Err.MINTING_COIN

        fees = removal_amount - addition_amount
        assert_fee_sum: uint64 = uint64(0)

        for npc in npc_list:
            if ConditionOpcode.RESERVE_FEE in npc.condition_dict:
                fee_list: List[ConditionVarPair] = npc.condition_dict[ConditionOpcode.RESERVE_FEE]
                for cvp in fee_list:
                    fee = int_from_bytes(cvp.vars[0])
                    assert_fee_sum = assert_fee_sum + fee
        if fees < assert_fee_sum:
            return (
                None,
                MempoolInclusionStatus.FAILED,
                Err.RESERVE_FEE_CONDITION_FAILED,
            )

        if cost == 0:
            return None, MempoolInclusionStatus.FAILED, Err.UNKNOWN

        fees_per_cost: float = fees / cost
        # If pool is at capacity check the fee, if not then accept even without the fee
        if self.mempool.at_full_capacity():
            if fees == 0:
                return None, MempoolInclusionStatus.FAILED, Err.INVALID_FEE_LOW_FEE
            if fees_per_cost < self.mempool.get_min_fee_rate():
                return None, MempoolInclusionStatus.FAILED, Err.INVALID_FEE_LOW_FEE
        # Check removals against UnspentDB + DiffStore + Mempool + SpendBundle
        # Use this information later when constructing a block
        fail_reason, conflicts = await self.check_removals(removal_record_dict)
        # If there is a mempool conflict check if this spendbundle has a higher fee per cost than all others
        tmp_error: Optional[Err] = None
        conflicting_pool_items: Dict[bytes32, MempoolItem] = {}
        if fail_reason is Err.MEMPOOL_CONFLICT:
            for conflicting in conflicts:
                sb: MempoolItem = self.mempool.removals[conflicting.name()]
                conflicting_pool_items[sb.name] = sb
            for item in conflicting_pool_items.values():
                if item.fee_per_cost >= fees_per_cost:
                    self.add_to_potential_tx_set(new_spend, spend_name, cost_result)
                    return (
                        uint64(cost),
                        MempoolInclusionStatus.PENDING,
                        Err.MEMPOOL_CONFLICT,
                    )

        elif fail_reason:
            return None, MempoolInclusionStatus.FAILED, fail_reason

        if tmp_error:
            return None, MempoolInclusionStatus.FAILED, tmp_error

        # Verify conditions, create hash_key list for aggsig check
        pks: List[G1Element] = []
        msgs: List[bytes32] = []
        error: Optional[Err] = None
        for npc in npc_list:
            coin_record: CoinRecord = removal_record_dict[npc.coin_name]
            # Check that the revealed removal puzzles actually match the puzzle hash
            if npc.puzzle_hash != coin_record.coin.puzzle_hash:
                log.warning("Mempool rejecting transaction because of wrong puzzle_hash")
                log.warning(f"{npc.puzzle_hash} != {coin_record.coin.puzzle_hash}")
                return None, MempoolInclusionStatus.FAILED, Err.WRONG_PUZZLE_HASH

            chialisp_height = (
                self.peak.prev_transaction_block_height if not self.peak.is_transaction_block else self.peak.height
            )
            error = mempool_check_conditions_dict(coin_record, new_spend, npc.condition_dict, uint32(chialisp_height))

            if error:
                if error is Err.ASSERT_HEIGHT_NOW_EXCEEDS_FAILED or error is Err.ASSERT_HEIGHT_AGE_EXCEEDS_FAILED:
                    self.add_to_potential_tx_set(new_spend, spend_name, cost_result)
                    return uint64(cost), MempoolInclusionStatus.PENDING, error
                break

            if validate_signature:
                for pk, message in pkm_pairs_for_conditions_dict(npc.condition_dict, npc.coin_name):
                    pks.append(pk)
                    msgs.append(message)
        if error:
            return None, MempoolInclusionStatus.FAILED, error

        if validate_signature:
            # Verify aggregated signature
            if not AugSchemeMPL.aggregate_verify(pks, msgs, new_spend.aggregated_signature):
                log.warning(f"Aggsig validation error {pks} {msgs} {new_spend}")
                return None, MempoolInclusionStatus.FAILED, Err.BAD_AGGREGATE_SIGNATURE
        # Remove all conflicting Coins and SpendBundles
        if fail_reason:
            mempool_item: MempoolItem
            for mempool_item in conflicting_pool_items.values():
                self.mempool.remove_spend(mempool_item)

        removals: List[Coin] = [coin for coin in removal_coin_dict.values()]
        new_item = MempoolItem(new_spend, uint64(fees), cost_result, spend_name, additions, removals)
        self.mempool.add_to_pool(new_item, additions, removal_coin_dict)
        log.info(f"add_spendbundle took {time.time() - start_time} seconds")
        return uint64(cost), MempoolInclusionStatus.SUCCESS, None
    async def fetch_blocks_and_validate(
        self,
        peer: WSChiaConnection,
        height_start: uint32,
        height_end: uint32,
        fork_point_with_peak: uint32,
    ) -> Tuple[bool, bool]:
        """
        Returns whether the blocks validated, and whether the peak was advanced

        """
        if self.wallet_state_manager is None:
            return False, False

        self.log.info(f"Requesting blocks {height_start}-{height_end}")
        request = RequestHeaderBlocks(uint32(height_start), uint32(height_end))
        res: Optional[RespondHeaderBlocks] = await peer.request_header_blocks(
            request)
        if res is None or not isinstance(res, RespondHeaderBlocks):
            raise ValueError("Peer returned no response")
        header_blocks: List[HeaderBlock] = res.header_blocks
        advanced_peak = False
        if header_blocks is None:
            raise ValueError(f"No response from peer {peer}")
        if (self.full_node_peer is not None
                and peer.peer_host == self.full_node_peer.host
                or peer.peer_host == "127.0.0.1"):
            trusted = True
            pre_validation_results: Optional[List[PreValidationResult]] = None
        else:
            trusted = False
            pre_validation_results = await self.wallet_state_manager.blockchain.pre_validate_blocks_multiprocessing(
                header_blocks)
            if pre_validation_results is None:
                return False, advanced_peak
            assert len(header_blocks) == len(pre_validation_results)

        for i in range(len(header_blocks)):
            header_block = header_blocks[i]
            if not trusted and pre_validation_results is not None and pre_validation_results[
                    i].error is not None:
                raise ValidationError(Err(pre_validation_results[i].error))

            fork_point_with_old_peak = None if advanced_peak else fork_point_with_peak
            if header_block.is_transaction_block:
                # Find additions and removals
                (
                    additions,
                    removals,
                ) = await self.wallet_state_manager.get_filter_additions_removals(
                    header_block, header_block.transactions_filter,
                    fork_point_with_old_peak)

                # Get Additions
                added_coins = await self.get_additions(peer, header_block,
                                                       additions)
                if added_coins is None:
                    raise ValueError("Failed to fetch additions")

                # Get removals
                removed_coins = await self.get_removals(
                    peer, header_block, added_coins, removals)
                if removed_coins is None:
                    raise ValueError("Failed to fetch removals")

                header_block_record = HeaderBlockRecord(
                    header_block, added_coins, removed_coins)
            else:
                header_block_record = HeaderBlockRecord(header_block, [], [])
            start_t = time.time()
            if trusted:
                (
                    result,
                    error,
                    fork_h,
                ) = await self.wallet_state_manager.blockchain.receive_block(
                    header_block_record, None, trusted,
                    fork_point_with_old_peak)
            else:
                assert pre_validation_results is not None
                (
                    result,
                    error,
                    fork_h,
                ) = await self.wallet_state_manager.blockchain.receive_block(
                    header_block_record, pre_validation_results[i], trusted,
                    fork_point_with_old_peak)
            self.log.debug(
                f"Time taken to validate {header_block.height} with fork "
                f"{fork_point_with_old_peak}: {time.time() - start_t}")
            if result == ReceiveBlockResult.NEW_PEAK:
                advanced_peak = True
                self.wallet_state_manager.state_changed("new_block")
            elif result == ReceiveBlockResult.INVALID_BLOCK:
                raise ValueError("Value error peer sent us invalid block")
        return True, advanced_peak
async def validate_block_body(
    constants: ConsensusConstants,
    sub_blocks: Dict[bytes32, SubBlockRecord],
    sub_height_to_hash: Dict[uint32, bytes32],
    block_store: BlockStore,
    coin_store: CoinStore,
    peak: Optional[SubBlockRecord],
    block: Union[FullBlock, UnfinishedBlock],
    sub_height: uint32,
    height: Optional[uint32],
    cached_cost_result: Optional[CostResult] = None,
) -> Optional[Err]:
    """
    This assumes the header block has been completely validated.
    Validates the transactions and body of the block. Returns None if everything
    validates correctly, or an Err if something does not validate.
    """
    if isinstance(block, FullBlock):
        assert sub_height == block.sub_block_height
        if height is not None:
            assert height == block.height
            assert block.is_block()
        else:
            assert not block.is_block()

    # 1. For non block sub-blocks, foliage block, transaction filter, transactions info, and generator must be empty
    # If it is a sub block but not a block, there is no body to validate. Check that all fields are None
    if block.foliage_sub_block.foliage_block_hash is None:
        if (block.foliage_block is not None
                or block.transactions_info is not None
                or block.transactions_generator is not None):
            return Err.NOT_BLOCK_BUT_HAS_DATA
        return None  # This means the sub-block is valid

    # 2. For blocks, foliage block, transaction filter, transactions info must not be empty
    if block.foliage_block is None or block.foliage_block.filter_hash is None or block.transactions_info is None:
        return Err.IS_BLOCK_BUT_NO_DATA

    # keeps track of the reward coins that need to be incorporated
    expected_reward_coins: Set[Coin] = set()

    # 3. The transaction info hash in the Foliage block must match the transaction info
    if block.foliage_block.transactions_info_hash != std_hash(
            block.transactions_info):
        return Err.INVALID_TRANSACTIONS_INFO_HASH

    # 4. The foliage block hash in the foliage sub block must match the foliage block
    if block.foliage_sub_block.foliage_block_hash != std_hash(
            block.foliage_block):
        return Err.INVALID_FOLIAGE_BLOCK_HASH

    # 5. The prev generators root must be valid
    # TODO(straya): implement prev generators

    # 6. The generator root must be the tree-hash of the generator (or zeroes if no generator)
    if block.transactions_generator is not None:
        if block.transactions_generator.get_tree_hash(
        ) != block.transactions_info.generator_root:
            return Err.INVALID_TRANSACTIONS_GENERATOR_ROOT
    else:
        if block.transactions_info.generator_root != bytes([0] * 32):
            return Err.INVALID_TRANSACTIONS_GENERATOR_ROOT

    # 7. The reward claims must be valid for the previous sub-blocks, and current block fees
    if sub_height > 0:
        # Add reward claims for all sub-blocks from the prev prev block, until the prev block (including the latter)
        prev_block = sub_blocks[block.foliage_block.prev_block_hash]

        assert prev_block.fees is not None
        pool_coin = create_pool_coin(
            prev_block.sub_block_height,
            prev_block.pool_puzzle_hash,
            calculate_pool_reward(prev_block.height),
        )
        farmer_coin = create_farmer_coin(
            prev_block.sub_block_height,
            prev_block.farmer_puzzle_hash,
            uint64(
                calculate_base_farmer_reward(prev_block.height) +
                prev_block.fees),
        )
        # Adds the previous block
        expected_reward_coins.add(pool_coin)
        expected_reward_coins.add(farmer_coin)

        # For the second block in the chain, don't go back further
        if prev_block.sub_block_height > 0:
            curr_sb = sub_blocks[prev_block.prev_hash]
            curr_height = curr_sb.height
            while not curr_sb.is_block:
                expected_reward_coins.add(
                    create_pool_coin(
                        curr_sb.sub_block_height,
                        curr_sb.pool_puzzle_hash,
                        calculate_pool_reward(curr_height),
                    ))
                expected_reward_coins.add(
                    create_farmer_coin(
                        curr_sb.sub_block_height,
                        curr_sb.farmer_puzzle_hash,
                        calculate_base_farmer_reward(curr_height),
                    ))
                curr_sb = sub_blocks[curr_sb.prev_hash]

    if set(block.transactions_info.reward_claims_incorporated
           ) != expected_reward_coins:
        return Err.INVALID_REWARD_COINS

    removals: List[bytes32] = []
    coinbase_additions: List[Coin] = list(expected_reward_coins)
    additions: List[Coin] = []
    npc_list: List[NPC] = []
    removals_puzzle_dic: Dict[bytes32, bytes32] = {}
    cost: uint64 = uint64(0)

    if block.transactions_generator is not None:
        # Get List of names removed, puzzles hashes for removed coins and conditions crated
        if cached_cost_result is not None:
            result: CostResult = cached_cost_result
        else:
            result = calculate_cost_of_program(
                block.transactions_generator,
                constants.CLVM_COST_RATIO_CONSTANT)
        cost = result.cost
        npc_list = result.npc_list

        # 8. Check that cost <= MAX_BLOCK_COST_CLVM
        if cost > constants.MAX_BLOCK_COST_CLVM:
            return Err.BLOCK_COST_EXCEEDS_MAX
        if result.error is not None:
            return Err(result.error)

        for npc in npc_list:
            removals.append(npc.coin_name)
            removals_puzzle_dic[npc.coin_name] = npc.puzzle_hash

        additions = additions_for_npc(npc_list)

    # 9. Check that the correct cost is in the transactions info
    if block.transactions_info.cost != cost:
        return Err.INVALID_BLOCK_COST

    additions_dic: Dict[bytes32, Coin] = {}
    # 10. Check additions for max coin amount
    for coin in additions + coinbase_additions:
        additions_dic[coin.name()] = coin
        if coin.amount >= constants.MAX_COIN_AMOUNT:
            return Err.COIN_AMOUNT_EXCEEDS_MAXIMUM

    # 11. Validate addition and removal roots
    root_error = validate_block_merkle_roots(
        block.foliage_block.additions_root,
        block.foliage_block.removals_root,
        additions + coinbase_additions,
        removals,
    )
    if root_error:
        return root_error

    # 12. The additions and removals must result in the correct filter
    byte_array_tx: List[bytes32] = []

    for coin in additions + coinbase_additions:
        byte_array_tx.append(bytearray(coin.puzzle_hash))
    for coin_name in removals:
        byte_array_tx.append(bytearray(coin_name))

    bip158: PyBIP158 = PyBIP158(byte_array_tx)
    encoded_filter = bytes(bip158.GetEncoded())
    filter_hash = std_hash(encoded_filter)

    if filter_hash != block.foliage_block.filter_hash:
        return Err.INVALID_TRANSACTIONS_FILTER_HASH

    # 13. Check for duplicate outputs in additions
    addition_counter = collections.Counter(
        _.name() for _ in additions + coinbase_additions)
    for k, v in addition_counter.items():
        if v > 1:
            return Err.DUPLICATE_OUTPUT

    # 14. Check for duplicate spends inside block
    removal_counter = collections.Counter(removals)
    for k, v in removal_counter.items():
        if v > 1:
            return Err.DOUBLE_SPEND

    # 15. Check if removals exist and were not previously spent. (unspent_db + diff_store + this_block)
    if peak is None or sub_height == 0:
        fork_sub_h: int = -1
    else:
        fork_sub_h = find_fork_point_in_chain(
            sub_blocks, peak, sub_blocks[block.prev_header_hash])

    if fork_sub_h == -1:
        coin_store_reorg_height = -1
    else:
        last_sb_in_common = sub_blocks[sub_height_to_hash[uint32(fork_sub_h)]]
        if last_sb_in_common.is_block:
            coin_store_reorg_height = last_sb_in_common.height
        else:
            coin_store_reorg_height = last_sb_in_common.height - 1

    # Get additions and removals since (after) fork_h but not including this block
    additions_since_fork: Dict[bytes32, Tuple[Coin, uint32]] = {}
    removals_since_fork: Set[bytes32] = set()
    coinbases_since_fork: Dict[bytes32, uint32] = {}

    if sub_height > 0:
        curr: Optional[FullBlock] = await block_store.get_full_block(
            block.prev_header_hash)
        assert curr is not None

        while curr.sub_block_height > fork_sub_h:
            removals_in_curr, additions_in_curr = curr.tx_removals_and_additions(
            )
            for c_name in removals_in_curr:
                removals_since_fork.add(c_name)
            for c in additions_in_curr:
                additions_since_fork[c.name()] = (c, curr.sub_block_height)

            for coinbase_coin in curr.get_included_reward_coins():
                additions_since_fork[coinbase_coin.name()] = (
                    coinbase_coin, curr.sub_block_height)
                coinbases_since_fork[
                    coinbase_coin.name()] = curr.sub_block_height
            if curr.sub_block_height == 0:
                break
            curr = await block_store.get_full_block(curr.prev_header_hash)
            assert curr is not None

    removal_coin_records: Dict[bytes32, CoinRecord] = {}
    for rem in removals:
        if rem in additions_dic:
            # Ephemeral coin
            rem_coin: Coin = additions_dic[rem]
            new_unspent: CoinRecord = CoinRecord(
                rem_coin,
                sub_height,
                uint32(0),
                False,
                False,
                block.foliage_block.timestamp,
            )
            removal_coin_records[new_unspent.name] = new_unspent
        else:
            unspent = await coin_store.get_coin_record(rem)
            if unspent is not None and unspent.confirmed_block_index <= coin_store_reorg_height:
                # Spending something in the current chain, confirmed before fork
                # (We ignore all coins confirmed after fork)
                if unspent.spent == 1 and unspent.spent_block_index <= coin_store_reorg_height:
                    # Check for coins spent in an ancestor block
                    return Err.DOUBLE_SPEND
                removal_coin_records[unspent.name] = unspent
            else:
                # This coin is not in the current heaviest chain, so it must be in the fork
                if rem not in additions_since_fork:
                    # Check for spending a coin that does not exist in this fork
                    # TODO: fix this, there is a consensus bug here
                    return Err.UNKNOWN_UNSPENT
                new_coin, confirmed_height = additions_since_fork[rem]
                new_coin_record: CoinRecord = CoinRecord(
                    new_coin,
                    confirmed_height,
                    uint32(0),
                    False,
                    (rem in coinbases_since_fork),
                    block.foliage_block.timestamp,
                )
                removal_coin_records[new_coin_record.name] = new_coin_record

            # This check applies to both coins created before fork (pulled from coin_store),
            # and coins created after fork (additions_since_fork)>
            if rem in removals_since_fork:
                # This coin was spent in the fork
                return Err.DOUBLE_SPEND

    removed = 0
    for unspent in removal_coin_records.values():
        removed += unspent.coin.amount

    added = 0
    for coin in additions:
        added += coin.amount

    # 16. Check that the total coin amount for added is <= removed
    if removed < added:
        return Err.MINTING_COIN

    fees = removed - added
    assert_fee_sum: uint64 = uint64(0)

    for npc in npc_list:
        if ConditionOpcode.ASSERT_FEE in npc.condition_dict:
            fee_list: List[ConditionVarPair] = npc.condition_dict[
                ConditionOpcode.ASSERT_FEE]
            for cvp in fee_list:
                fee = int_from_bytes(cvp.vars[0])
                assert_fee_sum = assert_fee_sum + fee

    # 17. Check that the assert fee sum <= fees
    if fees < assert_fee_sum:
        return Err.ASSERT_FEE_CONDITION_FAILED

    # 18. Check that the computed fees are equal to the fees in the block header
    if block.transactions_info.fees != fees:
        return Err.INVALID_BLOCK_FEE_AMOUNT

    # 19. Verify that removed coin puzzle_hashes match with calculated puzzle_hashes
    for unspent in removal_coin_records.values():
        if unspent.coin.puzzle_hash != removals_puzzle_dic[unspent.name]:
            return Err.WRONG_PUZZLE_HASH

    # 20. Verify conditions
    # create hash_key list for aggsig check
    pairs_pks = []
    pairs_msgs = []
    for npc in npc_list:
        assert height is not None
        unspent = removal_coin_records[npc.coin_name]
        error = blockchain_check_conditions_dict(
            unspent,
            removal_coin_records,
            npc.condition_dict,
            height,
            block.foliage_block.timestamp,
        )
        if error:
            return error
        for pk, m in pkm_pairs_for_conditions_dict(npc.condition_dict,
                                                   npc.coin_name):
            pairs_pks.append(pk)
            pairs_msgs.append(m)

    # 21. Verify aggregated signature
    # TODO: move this to pre_validate_blocks_multiprocessing so we can sync faster
    if not block.transactions_info.aggregated_signature:
        return Err.BAD_AGGREGATE_SIGNATURE

    if len(pairs_pks) == 0:
        if len(
                pairs_msgs
        ) != 0 or block.transactions_info.aggregated_signature != G2Element.infinity(
        ):
            return Err.BAD_AGGREGATE_SIGNATURE
    else:
        # noinspection PyTypeChecker
        validates = AugSchemeMPL.aggregate_verify(
            pairs_pks, pairs_msgs,
            block.transactions_info.aggregated_signature)
        if not validates:
            return Err.BAD_AGGREGATE_SIGNATURE

    return None
    async def fetch_blocks_and_validate(self, peer: WSChiaConnection, sub_height_start: uint32, sub_height_end: uint32):
        if self.wallet_state_manager is None:
            return

        self.log.info(f"Requesting blocks {sub_height_start}-{sub_height_end}")
        request = RequestHeaderBlocks(uint32(sub_height_start), uint32(sub_height_end))
        res: Optional[RespondHeaderBlocks] = await peer.request_header_blocks(request)
        if res is None or not isinstance(res, RespondHeaderBlocks):
            raise ValueError("Peer returned no response")
        header_blocks: List[HeaderBlock] = res.header_blocks
        if header_blocks is None:
            raise ValueError(f"No response from peer {peer}")
        if (
            self.full_node_peer is not None
            and peer.peer_host == self.full_node_peer.host
            or peer.peer_host == "127.0.0.1"
        ):
            trusted = True
            pre_validation_results: Optional[List[PreValidationResult]] = None
        else:
            trusted = False
            pre_validation_results = await self.wallet_state_manager.blockchain.pre_validate_blocks_multiprocessing(
                header_blocks
            )
            if pre_validation_results is None:
                return False
            assert len(header_blocks) == len(pre_validation_results)

        for i in range(len(header_blocks)):
            header_block = header_blocks[i]
            if not trusted and pre_validation_results is not None and pre_validation_results[i].error is not None:
                raise ValidationError(Err(pre_validation_results[i].error))
            if header_block.is_block:
                # Find additions and removals
                (additions, removals,) = await self.wallet_state_manager.get_filter_additions_removals(
                    header_block, header_block.transactions_filter
                )

                # Get Additions
                added_coins = await self.get_additions(peer, header_block, additions)
                if added_coins is None:
                    raise ValueError("Failed to fetch additions")

                # Get removals
                removed_coins = await self.get_removals(peer, header_block, added_coins, removals)
                if removed_coins is None:
                    raise ValueError("Failed to fetch removals")

                header_block_record = HeaderBlockRecord(header_block, added_coins, removed_coins)
            else:
                header_block_record = HeaderBlockRecord(header_block, [], [])

            if trusted:
                (
                    result,
                    error,
                    fork_h,
                ) = await self.wallet_state_manager.blockchain.receive_block(header_block_record, None, trusted)
            else:
                assert pre_validation_results is not None
                (result, error, fork_h,) = await self.wallet_state_manager.blockchain.receive_block(
                    header_block_record, pre_validation_results[i], trusted
                )
            if result == ReceiveBlockResult.NEW_PEAK:
                self.wallet_state_manager.state_changed("new_block")
            elif result == ReceiveBlockResult.INVALID_BLOCK:
                raise ValueError("Value error peer sent us invalid block")