From d5d5e8af5c77760e8e20a5565388b9acc337279b Mon Sep 17 00:00:00 2001
From: ThomasV <thomasv@electrum.org>
Date: Mon, 24 Jul 2017 08:46:49 +0200
Subject: [PATCH] fix: handle multiple forks at same checkpoint

---
 lib/network.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/lib/network.py b/lib/network.py
index 2d2e58fc..1a5f671e 100644
--- a/lib/network.py
+++ b/lib/network.py
@@ -835,13 +835,19 @@ class Network(util.DaemonThread):
                 if branch is not None:
                     if branch.check_header(interface.bad_header):
                         interface.print_error('joining chain', interface.bad)
+                        next_height = None
                     elif branch.parent().check_header(header):
                         interface.print_error('reorg', interface.bad, interface.tip)
                         interface.blockchain = branch.parent()
+                        next_height = None
                     else:
-                        # should not happen
-                        raise BaseException('error')
-                    next_height = None
+                        interface.print_error('checkpoint conflicts with existing fork', branch.path())
+                        open(branch.path(), 'w+').close()
+                        branch.save_header(interface.bad_header)
+                        interface.mode = 'catch_up'
+                        interface.blockchain = branch
+                        next_height = interface.bad + 1
+                        interface.blockchain.catch_up = interface.server
                 else:
                     bh = interface.blockchain.height()
                     next_height = None