Change the default calculation of min_lovelace to post alonzo

examples/native_token.py

@@ -15,7 +15,9 @@
 NETWORK = Network.TESTNET
 
 chain_context = BlockFrostChainContext(
-    project_id=BLOCK_FROST_PROJECT_ID, network=NETWORK
+    project_id=BLOCK_FROST_PROJECT_ID,
+    network=NETWORK,
+    base_url="https://cardano-preprod.blockfrost.io/api",
 )
 
 """Preparation"""
@@ -153,7 +155,9 @@ def load_or_create_key_pair(base_dir, base_name):
 builder.auxiliary_data = auxiliary_data
 
 # Calculate the minimum amount of lovelace that need to hold the NFT we are going to mint
-min_val = min_lovelace_pre_alonzo(Value(0, my_nft), chain_context)
+min_val = min_lovelace(
+    chain_context, output=TransactionOutput(address, Value(0, my_nft))
+)
 
 # Send the NFT to our own address
 builder.add_output(TransactionOutput(address, Value(min_val, my_nft)))

integration-test/test/test_min_utxo.py

@@ -0,0 +1,107 @@
+import pathlib
+import tempfile
+from dataclasses import dataclass
+
+import cbor2
+import pytest
+from retry import retry
+
+from pycardano import *
+
+from .base import TEST_RETRIES, TestBase
+
+
+class TestMint(TestBase):
+    @retry(tries=TEST_RETRIES, backoff=1.5, delay=6, jitter=(0, 4))
+    @pytest.mark.post_alonzo
+    def test_min_utxo(self):
+        address = Address(self.payment_vkey.hash(), network=self.NETWORK)
+
+        with open("./plutus_scripts/always_succeeds.plutus", "r") as f:
+            script_hex = f.read()
+            anymint_script = PlutusV1Script(cbor2.loads(bytes.fromhex(script_hex)))
+
+        policy_id = plutus_script_hash(anymint_script)
+
+        my_nft = MultiAsset.from_primitive(
+            {
+                policy_id.payload: {
+                    b"MY_SCRIPT_NFT_1": 1,  # Name of our NFT1  # Quantity of this NFT
+                    b"MY_SCRIPT_NFT_2": 1,  # Name of our NFT2  # Quantity of this NFT
+                }
+            }
+        )
+
+        metadata = {
+            721: {
+                policy_id.payload.hex(): {
+                    "MY_SCRIPT_NFT_1": {
+                        "description": "This is my first NFT thanks to PyCardano",
+                        "name": "PyCardano NFT example token 1",
+                        "id": 1,
+                        "image": "ipfs://QmRhTTbUrPYEw3mJGGhQqQST9k86v1DPBiTTWJGKDJsVFw",
+                    },
+                    "MY_SCRIPT_NFT_2": {
+                        "description": "This is my second NFT thanks to PyCardano",
+                        "name": "PyCardano NFT example token 2",
+                        "id": 2,
+                        "image": "ipfs://QmRhTTbUrPYEw3mJGGhQqQST9k86v1DPBiTTWJGKDJsVFw",
+                    },
+                }
+            }
+        }
+
+        # Place metadata in AuxiliaryData, the format acceptable by a transaction.
+        auxiliary_data = AuxiliaryData(AlonzoMetadata(metadata=Metadata(metadata)))
+
+        # Create a transaction builder
+        builder = TransactionBuilder(self.chain_context)
+
+        # Add our own address as the input address
+        builder.add_input_address(address)
+
+        @dataclass
+        class MyPlutusData(PlutusData):
+            a: int
+
+        # Add minting script with an empty datum and a minting redeemer
+        builder.add_minting_script(
+            anymint_script, redeemer=Redeemer(RedeemerTag.MINT, MyPlutusData(a=42))
+        )
+
+        # Set nft we want to mint
+        builder.mint = my_nft
+
+        # Set transaction metadata
+        builder.auxiliary_data = auxiliary_data
+
+        # Calculate the minimum amount of lovelace that need to hold the NFT we are going to mint
+        min_val = min_lovelace(
+            output=TransactionOutput(address, Value(0, my_nft)),
+            context=self.chain_context,
+        )
+
+        # Send the NFT to our own address
+        nft_output = TransactionOutput(address, Value(min_val, my_nft))
+        pure_ada_output = TransactionOutput(
+            address,
+            min_lovelace(
+                context=self.chain_context, output=TransactionOutput(address, 0)
+            ),
+        )
+        builder.add_output(nft_output)
+        builder.add_output(pure_ada_output)
+
+        # Build and sign transaction
+        signed_tx = builder.build_and_sign([self.payment_skey], address)
+        # signed_tx.transaction_witness_set.plutus_data
+
+        print("############### Transaction created ###############")
+        print(signed_tx)
+        print(signed_tx.to_cbor())
+
+        # Submit signed transaction to the network
+        print("############### Submitting transaction ###############")
+        self.chain_context.submit_tx(signed_tx.to_cbor())
+
+        self.assert_output(address, nft_output)

integration-test/test/test_mint.py

@@ -322,7 +322,7 @@ class MyPlutusData(PlutusData):
 
         # Calculate the minimum amount of lovelace that need to hold the NFT we are going to mint
         min_val = min_lovelace(
-            output=TransactionOutput(address, Value(1000000, my_nft)),
+            output=TransactionOutput(address, Value(0, my_nft)),
             context=self.chain_context,
         )
 

pycardano/backend/base.py

@@ -9,7 +9,12 @@
 from pycardano.plutus import ExecutionUnits
 from pycardano.transaction import UTxO
 
-__all__ = ["GenesisParameters", "ProtocolParameters", "ChainContext", "ALONZO_COINS_PER_UTXO_WORD"]
+__all__ = [
+    "GenesisParameters",
+    "ProtocolParameters",
+    "ChainContext",
+    "ALONZO_COINS_PER_UTXO_WORD",
+]
 
 ALONZO_COINS_PER_UTXO_WORD = 34482
 

pycardano/backend/blockfrost.py

@@ -7,7 +7,12 @@
 from blockfrost import ApiUrls, BlockFrostApi
 
 from pycardano.address import Address
-from pycardano.backend.base import ChainContext, GenesisParameters, ProtocolParameters, ALONZO_COINS_PER_UTXO_WORD
+from pycardano.backend.base import (
+    ALONZO_COINS_PER_UTXO_WORD,
+    ChainContext,
+    GenesisParameters,
+    ProtocolParameters,
+)
 from pycardano.exception import TransactionFailedException
 from pycardano.hash import SCRIPT_HASH_SIZE, DatumHash, ScriptHash
 from pycardano.nativescript import NativeScript

pycardano/coinselection.py

@@ -5,6 +5,7 @@
 import random
 from typing import Iterable, List, Optional, Tuple
 
+from pycardano.address import Address
 from pycardano.backend.base import ChainContext
 from pycardano.exception import (
     InputUTxODepletedException,
@@ -13,10 +14,14 @@
     UTxOSelectionException,
 )
 from pycardano.transaction import TransactionOutput, UTxO, Value
-from pycardano.utils import max_tx_fee, min_lovelace_pre_alonzo
+from pycardano.utils import max_tx_fee, min_lovelace_post_alonzo
 
 __all__ = ["UTxOSelector", "LargestFirstSelector", "RandomImproveMultiAsset"]
 
+_FAKE_ADDR = Address.from_primitive(
+    "addr1q8m9x2zsux7va6w892g38tvchnzahvcd9tykqf3ygnmwta8k2v59pcduem5uw253zwke30x9mwes62kfvqnzg38kuh6q966kg7"
+)
+
 
 class UTxOSelector:
     """UTxOSelector defines an interface through which a subset of UTxOs should be selected from a parent set
@@ -75,9 +80,9 @@ def select(
         utxos: List[UTxO],
         outputs: List[TransactionOutput],
         context: ChainContext,
-        max_input_count: int = None,
-        include_max_fee: bool = True,
-        respect_min_utxo: bool = True,
+        max_input_count: Optional[int] = None,
+        include_max_fee: Optional[bool] = True,
+        respect_min_utxo: Optional[bool] = True,
     ) -> Tuple[List[UTxO], Value]:
 
         available: List[UTxO] = sorted(utxos, key=lambda utxo: utxo.output.lovelace)
@@ -103,7 +108,9 @@ def select(
 
         if respect_min_utxo:
             change = selected_amount - total_requested
-            min_change_amount = min_lovelace_pre_alonzo(change, context, False)
+            min_change_amount = min_lovelace_post_alonzo(
+                TransactionOutput(_FAKE_ADDR, change), context
+            )
 
             if change.coin < min_change_amount:
                 additional, _ = self.select(
@@ -307,7 +314,9 @@ def select(
 
         if respect_min_utxo:
             change = selected_amount - request_sum
-            min_change_amount = min_lovelace_pre_alonzo(change, context, False)
+            min_change_amount = min_lovelace_post_alonzo(
+                TransactionOutput(_FAKE_ADDR, change), context
+            )
 
             if change.coin < min_change_amount:
                 additional, _ = self.select(

pycardano/transaction.py

@@ -371,6 +371,8 @@ class TransactionOutput(CBORSerializable):
 
     script: Optional[Union[NativeScript, PlutusV1Script, PlutusV2Script]] = None
 
+    post_alonzo: Optional[bool] = False
+
     def __post_init__(self):
         if isinstance(self.amount, int):
             self.amount = Value(self.amount)
@@ -398,7 +400,7 @@ def lovelace(self) -> int:
             return self.amount.coin
 
     def to_primitive(self) -> Primitive:
-        if self.datum or self.script:
+        if self.datum or self.script or self.post_alonzo:
             datum = (
                 _DatumOption(self.datum_hash or self.datum)
                 if self.datum is not None or self.datum_hash is not None

pycardano/txbuilder.py

@@ -55,13 +55,7 @@
     Value,
     Withdrawals,
 )
-from pycardano.utils import (
-    fee,
-    max_tx_fee,
-    min_lovelace_post_alonzo,
-    min_lovelace_pre_alonzo,
-    script_data_hash,
-)
+from pycardano.utils import fee, max_tx_fee, min_lovelace_post_alonzo, script_data_hash
 from pycardano.witness import TransactionWitnessSet, VerificationKeyWitness
 
 __all__ = ["TransactionBuilder"]
@@ -436,10 +430,12 @@ def _calc_change(
 
         # when there is only ADA left, simply use remaining coin value as change
         if not change.multi_asset:
-            if change.coin < min_lovelace_pre_alonzo(change, self.context):
+            if change.coin < min_lovelace_post_alonzo(
+                TransactionOutput(address, change), self.context
+            ):
                 raise InsufficientUTxOBalanceException(
                     f"Not enough ADA left for change: {change.coin} but needs "
-                    f"{min_lovelace_pre_alonzo(change, self.context)}"
+                    f"{min_lovelace_post_alonzo(TransactionOutput(address, change), self.context)}"
                 )
             lovelace_change = change.coin
             change_output_arr.append(TransactionOutput(address, lovelace_change))
@@ -456,8 +452,8 @@ def _calc_change(
                 # Combine remainder of provided ADA with last MultiAsset for output
                 # There may be rare cases where adding ADA causes size exceeds limit
                 # We will revisit if it becomes an issue
-                if change.coin < min_lovelace_pre_alonzo(
-                    Value(0, multi_asset), self.context
+                if change.coin < min_lovelace_post_alonzo(
+                    TransactionOutput(address, Value(0, multi_asset)), self.context
                 ):
                     raise InsufficientUTxOBalanceException(
                         "Not enough ADA left to cover non-ADA assets in a change address"
@@ -468,8 +464,8 @@ def _calc_change(
                     change_value = Value(change.coin, multi_asset)
                 else:
                     change_value = Value(0, multi_asset)
-                    change_value.coin = min_lovelace_pre_alonzo(
-                        change_value, self.context
+                    change_value.coin = min_lovelace_post_alonzo(
+                        TransactionOutput(address, change_value), self.context
                     )
 
                 change_output_arr.append(TransactionOutput(address, change_value))
@@ -560,7 +556,9 @@ def _adding_asset_make_output_overflow(
         attempt_amount = new_amount + current_amount
 
         # Calculate minimum ada requirements for more precise value size
-        required_lovelace = min_lovelace_pre_alonzo(attempt_amount, self.context)
+        required_lovelace = min_lovelace_post_alonzo(
+            TransactionOutput(output.address, attempt_amount), self.context
+        )
         attempt_amount.coin = required_lovelace
 
         return len(attempt_amount.to_cbor("bytes")) > max_val_size
@@ -617,7 +615,9 @@ def _pack_tokens_for_change(
 
             # Calculate min lovelace required for more precise size
             updated_amount = deepcopy(output.amount)
-            required_lovelace = min_lovelace_pre_alonzo(updated_amount, self.context)
+            required_lovelace = min_lovelace_post_alonzo(
+                TransactionOutput(change_address, updated_amount), self.context
+            )
             updated_amount.coin = required_lovelace
 
             if len(updated_amount.to_cbor("bytes")) > max_val_size:
@@ -903,8 +903,11 @@ def build(
                 unfulfilled_amount.coin = max(
                     0,
                     unfulfilled_amount.coin
-                    + min_lovelace_pre_alonzo(
-                        selected_amount - trimmed_selected_amount, self.context
+                    + min_lovelace_post_alonzo(
+                        TransactionOutput(
+                            change_address, selected_amount - trimmed_selected_amount
+                        ),
+                        self.context,
                     ),
                 )
         else:

pycardano/utils.py

@@ -162,8 +162,25 @@ def min_lovelace_post_alonzo(output: TransactionOutput, context: ChainContext) -
         int: Minimum required lovelace amount for this transaction output.
     """
     constant_overhead = 160
+
+    amt = output.amount
+
+    # If the amount of ADA is 0, a default value of 1 ADA will be used
+    if amt.coin == 0:
+        amt.coin = 1000000
+
+    # Make sure we are using post-alonzo output
+    tmp_out = TransactionOutput(
+        output.address,
+        output.amount,
+        output.datum_hash,
+        output.datum,
+        output.script,
+        True,
+    )
+
     return (
-        constant_overhead + len(output.to_cbor("bytes"))
+        constant_overhead + len(tmp_out.to_cbor("bytes"))
     ) * context.protocol_param.coins_per_utxo_byte
 
 

test/pycardano/test_txbuilder.py

@@ -367,13 +367,13 @@ def test_tx_add_change_split_nfts(chain_context):
             # Change output
             [
                 sender_address.to_primitive(),
-                [1344798, {b"1111111111111111111111111111": {b"Token1": 1}}],
+                [1034400, {b"1111111111111111111111111111": {b"Token1": 1}}],
             ],
             # Second change output from split due to change size limit exceed
             # Fourth output as change
             [
                 sender_address.to_primitive(),
-                [2482969, {b"1111111111111111111111111111": {b"Token2": 2}}],
+                [2793367, {b"1111111111111111111111111111": {b"Token2": 2}}],
             ],
         ],
         2: 172233,
@@ -407,7 +407,7 @@ def test_tx_add_change_split_nfts_not_enough_add(chain_context):
     # Add sender address as input
     mint = {policy_id.payload: {b"Token3": 1}}
     tx_builder.add_input_address(sender).add_output(
-        TransactionOutput.from_primitive([sender, 7000000])
+        TransactionOutput.from_primitive([sender, 8000000])
     )
     tx_builder.mint = MultiAsset.from_primitive(mint)
     tx_builder.native_scripts = [script]