Merge multiple outputs to same address

electrum/transaction.py

@@ -613,6 +613,15 @@ def check_scriptpubkey_template_and_dust(scriptpubkey, amount: Optional[int]):
     if amount < dust_limit:
         raise Exception(f'amount ({amount}) is below dust limit for scriptpubkey type ({dust_limit})')
 
+def merge_tx_outputs(outputs):
+    output_dict = {}
+    for output in outputs:
+        if output.scriptpubkey in output_dict:
+            output_dict[output.scriptpubkey].value += output.value
+        else:
+            output_dict[output.scriptpubkey] = copy.copy(output)
+
+    return list(output_dict.values())
 
 def match_script_against_template(script, template, debug=False) -> bool:
     """Returns whether 'script' matches 'template'."""
@@ -2042,6 +2051,7 @@ class PartialTransaction(Transaction):
 
     def add_outputs(self, outputs: List[PartialTxOutput]) -> None:
         self._outputs.extend(outputs)
+        self._outputs = merge_tx_outputs(self._outputs)
         self.BIP69_sort(inputs=False)
         self.invalidate_ser_cache()
 

electrum/wallet.py

@@ -1792,19 +1792,20 @@ class Abstract_Wallet(ABC, Logger, EventListener):
                     lower_bound = max(lower_bound_feerate, lower_bound_relayfee)
                     return max(lower_bound, original_fee_estimator(size))
                 txi = base_tx.inputs()
-                txo = list(filter(lambda o: not self.is_change(o.address), base_tx.outputs()))
+                txo = list(filter(lambda o: not self.is_change(o.address), base_tx.outputs())) + list(outputs)
+                txo = transaction.merge_tx_outputs(txo)
                 old_change_addrs = [o.address for o in base_tx.outputs() if self.is_change(o.address)]
                 rbf_merge_txid = base_tx.txid()
             else:
                 txi = []
-                txo = []
+                txo = list(outputs)
                 old_change_addrs = []
             # change address. if empty, coin_chooser will set it
             change_addrs = self.get_change_addresses_for_new_transaction(change_addr or old_change_addrs)
             tx = coin_chooser.make_tx(
                 coins=coins,
                 inputs=txi,
-                outputs=list(outputs) + txo,
+                outputs=txo,
                 change_addrs=change_addrs,
                 fee_estimator_vb=fee_estimator,
                 dust_threshold=self.dust_threshold())