From f7ba881bc669451a60fedac58a449794702a3e23 Mon Sep 17 00:00:00 2001
From: Russell Yanofsky <russ@yanofsky.org>
Date: Tue, 21 Jan 2020 15:00:33 -0500
Subject: wallet: Avoid use of Chain::Lock in listsinceblock

This is a step toward removing the Chain::Lock class and reducing cs_main
locking.

This change only affects behavior in the case where wallet last block processed
falls behind the chain tip. Previously listsinceblock might not have returned
all transactions up to the claimed "lastblock" value in this case, resulting in
race conditions and potentially missing transactions in cases where
listsinceblock was called in a loop like
https://github.com/bitcoin/bitcoin/issues/14338#issuecomment-426706574
---
 src/test/interfaces_tests.cpp | 37 +++++++++++++++++++++++++++++++++++++
 1 file changed, 37 insertions(+)

(limited to 'src/test/interfaces_tests.cpp')

diff --git a/src/test/interfaces_tests.cpp b/src/test/interfaces_tests.cpp
index caa988df0..f95743ec4 100644
--- a/src/test/interfaces_tests.cpp
+++ b/src/test/interfaces_tests.cpp
@@ -2,7 +2,10 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <chainparams.h>
+#include <consensus/validation.h>
 #include <interfaces/chain.h>
+#include <script/standard.h>
 #include <test/util/setup_common.h>
 #include <validation.h>
 
@@ -44,6 +47,16 @@ BOOST_AUTO_TEST_CASE(findBlock)
     BOOST_CHECK(!chain->findBlock({}, FoundBlock()));
 }
 
+BOOST_AUTO_TEST_CASE(findAncestorByHeight)
+{
+    auto chain = interfaces::MakeChain(m_node);
+    auto& active = ChainActive();
+    uint256 hash;
+    BOOST_CHECK(chain->findAncestorByHeight(active[20]->GetBlockHash(), 10, FoundBlock().hash(hash)));
+    BOOST_CHECK_EQUAL(hash, active[10]->GetBlockHash());
+    BOOST_CHECK(!chain->findAncestorByHeight(active[10]->GetBlockHash(), 20));
+}
+
 BOOST_AUTO_TEST_CASE(findAncestorByHash)
 {
     auto chain = interfaces::MakeChain(m_node);
@@ -54,4 +67,28 @@ BOOST_AUTO_TEST_CASE(findAncestorByHash)
     BOOST_CHECK(!chain->findAncestorByHash(active[10]->GetBlockHash(), active[20]->GetBlockHash()));
 }
 
+BOOST_AUTO_TEST_CASE(findCommonAncestor)
+{
+    auto chain = interfaces::MakeChain(m_node);
+    auto& active = ChainActive();
+    auto* orig_tip = active.Tip();
+    for (int i = 0; i < 10; ++i) {
+        BlockValidationState state;
+        ChainstateActive().InvalidateBlock(state, Params(), active.Tip());
+    }
+    BOOST_CHECK_EQUAL(active.Height(), orig_tip->nHeight - 10);
+    coinbaseKey.MakeNewKey(true);
+    for (int i = 0; i < 20; ++i) {
+        CreateAndProcessBlock({}, GetScriptForRawPubKey(coinbaseKey.GetPubKey()));
+    }
+    BOOST_CHECK_EQUAL(active.Height(), orig_tip->nHeight + 10);
+    uint256 fork_hash;
+    int fork_height;
+    int orig_height;
+    BOOST_CHECK(chain->findCommonAncestor(orig_tip->GetBlockHash(), active.Tip()->GetBlockHash(), FoundBlock().height(fork_height).hash(fork_hash), FoundBlock().height(orig_height)));
+    BOOST_CHECK_EQUAL(orig_height, orig_tip->nHeight);
+    BOOST_CHECK_EQUAL(fork_height, orig_tip->nHeight - 10);
+    BOOST_CHECK_EQUAL(fork_hash, active[fork_height]->GetBlockHash());
+}
+
 BOOST_AUTO_TEST_SUITE_END()
-- 
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