Reference UTxOs are UTxOs (not TransactionInputs) (#181)

* Make reference inputs also UTxOs

They are used as UTxOs in the scripts too

* Fix None reference inputs if none given

* Allow TransactionInputs too, collect inputs as sets

Author: nielstron

docs/source/guides/transaction.rst

@@ -147,7 +147,7 @@ Step 6
 Add additional transaction information as needed:
 
     >>> builder.ttl = 3600
-    >>> builder.reference_inputs.add(tx_in)
+    >>> builder.reference_inputs.add(utxo)
 
 Step 7
 

pycardano/txbuilder.py

@@ -106,7 +106,7 @@ class TransactionBuilder:
 
     withdrawals: Optional[Withdrawals] = field(default=None)
 
-    reference_inputs: Set[TransactionInput] = field(
+    reference_inputs: Set[Union[UTxO, TransactionInput]] = field(
         init=False, default_factory=lambda: set()
     )
 
@@ -237,19 +237,19 @@ def add_script_input(
 
         if utxo.output.script:
             self._inputs_to_scripts[utxo] = utxo.output.script
-            self.reference_inputs.add(utxo.input)
+            self.reference_inputs.add(utxo)
             self._reference_scripts.append(utxo.output.script)
         elif not script:
             for i in self.context.utxos(str(utxo.output.address)):
                 if i.output.script:
                     self._inputs_to_scripts[utxo] = i.output.script
-                    self.reference_inputs.add(i.input)
+                    self.reference_inputs.add(i)
                     self._reference_scripts.append(i.output.script)
                     break
         elif isinstance(script, UTxO):
             assert script.output.script is not None
             self._inputs_to_scripts[utxo] = script.output.script
-            self.reference_inputs.add(script.input)
+            self.reference_inputs.add(script)
             self._reference_scripts.append(script.output.script)
         else:
             self._inputs_to_scripts[utxo] = script
@@ -283,7 +283,7 @@ def add_minting_script(
         if isinstance(script, UTxO):
             assert script.output.script is not None
             self._minting_script_to_redeemers.append((script.output.script, redeemer))
-            self.reference_inputs.add(script.input)
+            self.reference_inputs.add(script)
             self._reference_scripts.append(script.output.script)
         else:
             self._minting_script_to_redeemers.append((script, redeemer))
@@ -772,7 +772,11 @@ def _build_tx_body(self) -> TransactionBody:
             withdraws=self.withdrawals,
             collateral_return=self._collateral_return,
             total_collateral=self._total_collateral,
-            reference_inputs=list(self.reference_inputs) or None,
+            reference_inputs=[
+                i.input if isinstance(i, UTxO) else i for i in self.reference_inputs
+            ]
+            if self.reference_inputs
+            else None,
         )
         return tx_body