From 8a7c3447b3924aa313e7738e0ad85cd9b33044fa Mon Sep 17 00:00:00 2001
From: SomberNight <somber.night@protonmail.com>
Date: Thu, 7 Nov 2019 02:24:16 +0100
Subject: [PATCH] tx dialog: try harder to show fee

---
 electrum/address_synchronizer.py |  4 +++-
 electrum/transaction.py          | 16 +++++++++++++---
 electrum/wallet.py               |  2 ++
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/electrum/address_synchronizer.py b/electrum/address_synchronizer.py
index 985932cea..f40e3fc37 100644
--- a/electrum/address_synchronizer.py
+++ b/electrum/address_synchronizer.py
@@ -31,7 +31,7 @@ from typing import TYPE_CHECKING, Dict, Optional, Set, Tuple, NamedTuple, Sequen
 from . import bitcoin
 from .bitcoin import COINBASE_MATURITY
 from .util import profiler, bfh, TxMinedInfo
-from .transaction import Transaction, TxOutput, TxInput, PartialTxInput, TxOutpoint
+from .transaction import Transaction, TxOutput, TxInput, PartialTxInput, TxOutpoint, PartialTransaction
 from .synchronizer import Synchronizer
 from .verifier import SPV
 from .blockchain import hash_header
@@ -650,6 +650,8 @@ class AddressSynchronizer(Logger):
                         break
                 else:
                     value = None
+                if value is None:
+                    value = txin.value_sats()
                 if value is None:
                     is_pruned = True
                 else:
diff --git a/electrum/transaction.py b/electrum/transaction.py
index 872fb4ce9..7fe98c798 100644
--- a/electrum/transaction.py
+++ b/electrum/transaction.py
@@ -81,6 +81,10 @@ class MalformedBitcoinScript(Exception):
     pass
 
 
+class MissingTxInputAmount(Exception):
+    pass
+
+
 SIGHASH_ALL = 1
 
 
@@ -1605,13 +1609,19 @@ class PartialTransaction(Transaction):
         self.invalidate_ser_cache()
 
     def input_value(self) -> int:
-        return sum(txin.value_sats() for txin in self.inputs())
+        input_values = [txin.value_sats() for txin in self.inputs()]
+        if any([val is None for val in input_values]):
+            raise MissingTxInputAmount()
+        return sum(input_values)
 
     def output_value(self) -> int:
         return sum(o.value for o in self.outputs())
 
-    def get_fee(self) -> int:
-        return self.input_value() - self.output_value()
+    def get_fee(self) -> Optional[int]:
+        try:
+            return self.input_value() - self.output_value()
+        except MissingTxInputAmount:
+            return None
 
     def serialize_preimage(self, txin_index: int, *,
                            bip143_shared_txdigest_fields: BIP143SharedTxDigestFields = None) -> str:
diff --git a/electrum/wallet.py b/electrum/wallet.py
index a11bd397f..8e258dc1e 100644
--- a/electrum/wallet.py
+++ b/electrum/wallet.py
@@ -457,6 +457,8 @@ class Abstract_Wallet(AddressSynchronizer):
 
     def get_tx_info(self, tx) -> TxWalletDetails:
         is_relevant, is_mine, v, fee = self.get_wallet_delta(tx)
+        if fee is None and isinstance(tx, PartialTransaction):
+            fee = tx.get_fee()
         exp_n = None
         can_broadcast = False
         can_bump = False