From d7c2e4e9b36cc96718d67052de38cb96f45a613c Mon Sep 17 00:00:00 2001
From: Lex Berezhny <lex@damoti.com>
Date: Sat, 4 May 2019 17:22:32 -0400
Subject: [PATCH] fixed bug where lbrynet failed to start with single-key
 accounts in the wallet

---
 lbrynet/wallet/account.py         | 11 ++++++-----
 tests/unit/wallet/test_account.py | 17 +++++++++++++++++
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/lbrynet/wallet/account.py b/lbrynet/wallet/account.py
index 23c7da7f7..9b6e2165d 100644
--- a/lbrynet/wallet/account.py
+++ b/lbrynet/wallet/account.py
@@ -4,7 +4,7 @@ import binascii
 from hashlib import sha256
 from string import hexdigits
 
-from torba.client.baseaccount import BaseAccount
+from torba.client.baseaccount import BaseAccount, HierarchicalDeterministic
 from torba.client.basetransaction import TXORef
 
 
@@ -167,10 +167,11 @@ class Account(BaseAccount):
             ))
 
     async def save_max_gap(self):
-        gap = await self.get_max_gap()
-        self.receiving.gap = max(20, gap['max_receiving_gap'] + 1)
-        self.change.gap = max(6, gap['max_change_gap'] + 1)
-        self.wallet.save()
+        if issubclass(self.address_generator, HierarchicalDeterministic):
+            gap = await self.get_max_gap()
+            self.receiving.gap = max(20, gap['max_receiving_gap'] + 1)
+            self.change.gap = max(6, gap['max_change_gap'] + 1)
+            self.wallet.save()
 
     def get_balance(self, confirmations=0, include_claims=False, **constraints):
         if not include_claims:
diff --git a/tests/unit/wallet/test_account.py b/tests/unit/wallet/test_account.py
index 1fdbd4f2e..70dd98f03 100644
--- a/tests/unit/wallet/test_account.py
+++ b/tests/unit/wallet/test_account.py
@@ -95,3 +95,20 @@ class TestAccount(AsyncioTestCase):
         account = Account.from_dict(self.ledger, Wallet(), account_data)
         account_data['ledger'] = 'lbc_mainnet'
         self.assertDictEqual(account_data, account.to_dict())
+
+    async def test_save_max_gap(self):
+        account = Account.generate(
+            self.ledger, Wallet(), 'lbryum', {
+                    'name': 'deterministic-chain',
+                    'receiving': {'gap': 3, 'maximum_uses_per_address': 2},
+                    'change': {'gap': 4, 'maximum_uses_per_address': 2}
+                }
+        )
+        self.assertEqual(account.receiving.gap, 3)
+        self.assertEqual(account.change.gap, 4)
+        await account.save_max_gap()
+        self.assertEqual(account.receiving.gap, 20)
+        self.assertEqual(account.change.gap, 6)
+        # doesn't fail for single-address account
+        account2 = Account.generate(self.ledger, Wallet(), 'lbryum', {'name': 'single-address'})
+        await account2.save_max_gap()