Fix max tx fee

Author: cffls

pycardano/txbuilder.py

@@ -1041,24 +1041,26 @@ def _ensure_no_input_exclusion_conflict(self):
                 f"{intersection}."
             )
 
-    def _estimate_fee(self):
-        plutus_execution_units = ExecutionUnits(0, 0)
-        for redeemer in self._redeemer_list:
-            plutus_execution_units += redeemer.ex_units
-
+    def _ref_script_size(self):
         ref_script_size = 0
         for s in self._reference_scripts:
             if isinstance(s, NativeScript):
                 ref_script_size += len(s.to_cbor())
             else:
                 ref_script_size += len(s)
+        return ref_script_size
+
+    def _estimate_fee(self):
+        plutus_execution_units = ExecutionUnits(0, 0)
+        for redeemer in self._redeemer_list:
+            plutus_execution_units += redeemer.ex_units
 
         estimated_fee = fee(
             self.context,
             len(self._build_full_fake_tx().to_cbor()),
             plutus_execution_units.steps,
             plutus_execution_units.mem,
-            ref_script_size,
+            self._ref_script_size(),
         )
         if self.fee_buffer is not None:
             estimated_fee += self.fee_buffer
@@ -1314,7 +1316,7 @@ def _set_collateral_return(self, collateral_return_address: Optional[Address]):
             return
 
         collateral_amount = (
-            max_tx_fee(context=self.context)
+            max_tx_fee(context=self.context, ref_script_size=self._ref_script_size())
             * self.context.protocol_param.collateral_percent
             // 100
         )

pycardano/utils.py

@@ -97,11 +97,12 @@ def fee(
     )
 
 
-def max_tx_fee(context: ChainContext) -> int:
+def max_tx_fee(context: ChainContext, ref_script_size: int = 0) -> int:
     """Calculate the maximum possible transaction fee based on protocol parameters.
 
     Args:
         context (ChainContext): A chain context.
+        ref_script_size (int): Size of reference scripts in the transaction.
 
     Returns:
         int: Maximum possible tx fee in lovelace.
@@ -111,6 +112,7 @@ def max_tx_fee(context: ChainContext) -> int:
         context.protocol_param.max_tx_size,
         context.protocol_param.max_tx_ex_steps,
         context.protocol_param.max_tx_ex_mem,
+        ref_script_size,
     )
 
 

test/pycardano/util.py

@@ -46,7 +46,7 @@ class FixedChainContext(ChainContext):
         coins_per_utxo_word=34482,
         coins_per_utxo_byte=4310,
         cost_models={},
-        min_fee_reference_scripts={"base": 25600, "range": 44, "multiplier": 1.2},
+        min_fee_reference_scripts={"base": 44, "range": 25600, "multiplier": 1.2},
         maximum_reference_scripts_size={"bytes": 200_000},
     )