electrum

commit 0ddccd56c70a5629618065c30526dcc38b9cdc90
parent 5b9b6a931d0a05629511dd743a5ff326e80261ca
Author: SomberNight <somber.night@protonmail.com>
Date:   Mon, 10 Dec 2018 17:46:37 +0100

interface: fix only-genesis regtest case

Diffstat:
M
electrum/interface.py
 | 
7
+++++--

1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/electrum/interface.py b/electrum/interface.py
@@ -438,14 +438,17 @@ class Interface(PrintError):
         return last, height
 
     async def step(self, height, header=None):
-        assert height != 0
-        assert height <= self.tip, (height, self.tip)
+        assert 0 <= height <= self.tip, (height, self.tip)
         if header is None:
             header = await self.get_block_header(height, 'catchup')
 
         chain = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
         if chain:
             self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
+            # note: there is an edge case here that is not handled.
+            # we might know the blockhash (enough for check_header) but
+            # not have the header itself. e.g. regtest chain with only genesis.
+            # this situation resolves itself on the next block
             return 'catchup', height+1
 
         can_connect = blockchain.can_connect(header) if 'mock' not in header else header['mock']['connect'](height)