refactor(verification): refactor verify_sum

hathor/transaction/token_creation_tx.py

@@ -15,10 +15,13 @@
 from struct import error as StructError, pack
 from typing import Any, Optional
 
+from typing_extensions import override
+
 from hathor.transaction.base_transaction import TxInput, TxOutput, TxVersion
 from hathor.transaction.storage import TransactionStorage  # noqa: F401
-from hathor.transaction.transaction import Transaction
+from hathor.transaction.transaction import TokenInfo, Transaction
 from hathor.transaction.util import VerboseCallback, int_to_bytes, unpack, unpack_len
+from hathor.types import TokenUid
 
 # Signal bits (B), version (B), inputs len (B), outputs len (B)
 _FUNDS_FORMAT_STRING = '!BBBB'
@@ -213,6 +216,16 @@ def to_json_extended(self) -> dict[str, Any]:
         json['tokens'] = []
         return json
 
+    @override
+    def get_token_info_from_inputs(self) -> dict[TokenUid, TokenInfo]:
+        token_dict = super().get_token_info_from_inputs()
+
+        # we add the created token's info to token_dict, as the creation tx allows for mint/melt
+        assert self.hash is not None
+        token_dict[self.hash] = TokenInfo(0, True, True)
+
+        return token_dict
+
 
 def decode_string_utf8(encoded: bytes, key: str) -> str:
     """ Raises StructError in case it's not a valid utf-8 string

hathor/verification/token_creation_transaction_verifier.py

@@ -12,10 +12,11 @@
 #  See the License for the specific language governing permissions and
 #  limitations under the License.
 
+from hathor.transaction import Transaction
 from hathor.transaction.exceptions import InvalidToken, TransactionDataError
 from hathor.transaction.token_creation_tx import TokenCreationTransaction
-from hathor.transaction.transaction import TokenInfo, Transaction
 from hathor.transaction.util import clean_token_string
+from hathor.util import not_none
 from hathor.verification.transaction_verifier import TransactionVerifier
 
 
@@ -39,20 +40,14 @@ def verify_sum(self, tx: Transaction) -> None:
         :raises InputOutputMismatch: if sum of inputs is not equal to outputs and there's no mint/melt
         """
         assert isinstance(tx, TokenCreationTransaction)
-        token_dict = tx.get_token_info_from_inputs()
-
-        # we add the created token's info to token_dict, as the creation tx allows for mint/melt
-        assert tx.hash is not None
-        token_dict[tx.hash] = TokenInfo(0, True, True)
-
-        self.update_token_info_from_outputs(tx, token_dict=token_dict)
+        token_dict = self.get_complete_token_info(tx)
 
         # make sure tokens are being minted
-        token_info = token_dict[tx.hash]
+        token_info = token_dict[not_none(tx.hash)]
         if token_info.amount <= 0:
             raise InvalidToken('Token creation transaction must mint new tokens')
 
-        self.verify_authorities_and_deposit(token_dict)
+        super().verify_sum(tx)
 
     def verify_token_info(self, tx: TokenCreationTransaction) -> None:
         """ Validates token info

hathor/verification/transaction_verifier.py

@@ -186,8 +186,7 @@ def verify_sum(self, tx: Transaction) -> None:
         :raises InvalidToken: when there's an error in token operations
         :raises InputOutputMismatch: if sum of inputs is not equal to outputs and there's no mint/melt
         """
-        token_dict = tx.get_token_info_from_inputs()
-        self.update_token_info_from_outputs(tx, token_dict=token_dict)
+        token_dict = self.get_complete_token_info(tx)
         self.verify_authorities_and_deposit(token_dict)
 
     def verify_reward_locked(self, tx: Transaction) -> None:
@@ -290,3 +289,12 @@ def update_token_info_from_outputs(self, tx: Transaction, *, token_dict: dict[To
                     # for regular outputs, just subtract from the total amount
                     sum_tokens = token_info.amount + tx_output.value
                     token_dict[token_uid] = TokenInfo(sum_tokens, token_info.can_mint, token_info.can_melt)
+
+    def get_complete_token_info(self, tx: Transaction) -> dict[TokenUid, TokenInfo]:
+        """
+        Get a complete token info dict, including data from both inputs and outputs.
+        """
+        token_dict = tx.get_token_info_from_inputs()
+        self.update_token_info_from_outputs(tx, token_dict=token_dict)
+
+        return token_dict