feat: return none instead of raising an error

Author: r4mmer

hathor/nanocontracts/runner/runner.py

@@ -1317,16 +1317,17 @@ def _get_token(self, token_uid: TokenUid) -> TokenDescription:
             )
 
         try:
-            return self.tx_storage.get_token_description(token_uid)
+            token_description = self.tx_storage.get_token_description(token_uid)
+            if token_description is None:
+                raise NCInvalidSyscall(
+                    f'The {token_uid.hex()} token is not confirmed by any block '
+                    f'for contract {call_record.contract_id.hex()}'
+                )
+            return token_description
         except TransactionDoesNotExist:
             raise NCInvalidSyscall(
                 f'contract {call_record.contract_id.hex()} could not find {token_uid.hex()} token'
             )
-        except TransactionMetadataDoesNotExist:
-            raise NCInvalidSyscall(
-                f'The {token_uid.hex()} token is not confirmed by any block '
-                f'for contract {call_record.contract_id.hex()}'
-            )
 
     def _create_token(
         self,

hathor/transaction/storage/transaction_storage.py

@@ -37,7 +37,6 @@
     TokenCreationTransactionDoesNotExist,
     TransactionDoesNotExist,
     TransactionIsNotABlock,
-    TransactionMetadataDoesNotExist,
     TransactionNotInAllowedScopeError,
 )
 from hathor.transaction.storage.migrations import (
@@ -577,22 +576,19 @@ def get_token_creation_transaction(self, hash_bytes: bytes) -> TokenCreationTran
             raise TokenCreationTransactionDoesNotExist(hash_bytes)
         return tx
 
-    def get_token_description(self, token_uid: bytes) -> TokenDescription:
+    def get_token_description(self, token_uid: bytes) -> Optional[TokenDescription]:
         """Get the confirmed token description for `token_uid`.
 
         :param token_uid: Unique token id to fetch.
         :raises TransactionDoesNotExist: If the transaction with the given hash does not exist.
         :raises TokenCreationTransactionDoesNotExist: If the transaction exists but is not a TokenCreationTransaction.
-        :raises TransactionMetadataDoesNotExist: The tx that creates this token has not been confirmed by any block.
         :return: The TokenCreationTransaction instance.
         """
         # Check the transaction storage for existing tokens
         token_creation_tx = self.get_token_creation_transaction(token_uid)
 
         if token_creation_tx.get_metadata().first_block is None:
-            raise TransactionMetadataDoesNotExist(
-                f"The {token_uid.hex()} token is not confirmed by any block"
-            )
+            return None
 
         return TokenDescription(
             token_version=token_creation_tx.token_version,