From 2013b35e3ef1588547a35825dcdf73e202d135b2 Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@electriccoin.co>
Date: Mon, 6 Apr 2020 14:40:56 -0600
Subject: [PATCH 1/3] Remove option to load new blocks from ConnectTip

---
 src/main.cpp | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 85914e54e..4855e29f2 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3212,15 +3212,9 @@ uint64_t nNotifiedSequence = 0;
  */
 bool static ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const CBlock* pblock)
 {
-    assert(pindexNew->pprev == chainActive.Tip());
+    assert(pblock && pindexNew->pprev == chainActive.Tip());
     // Read block from disk.
     int64_t nTime1 = GetTimeMicros();
-    CBlock block;
-    if (!pblock) {
-        if (!ReadBlockFromDisk(block, pindexNew, chainparams.GetConsensus()))
-            return AbortNode(state, "Failed to read block");
-        pblock = &block;
-    }
     // Apply the block atomically to the chain state.
     int64_t nTime2 = GetTimeMicros(); nTimeReadFromDisk += nTime2 - nTime1;
     int64_t nTime3;
@@ -3431,7 +3425,17 @@ static bool ActivateBestChainStep(CValidationState& state, const CChainParams& c
 
         // Connect new blocks.
         BOOST_REVERSE_FOREACH(CBlockIndex *pindexConnect, vpindexToConnect) {
-            if (!ConnectTip(state, chainparams, pindexConnect, pindexConnect == pindexMostWork ? pblock : NULL)) {
+            const CBlock* pconnectBlock = pblock;
+            CBlock block;
+            if (pindexConnect != pindexMostWork) {
+                if (!ReadBlockFromDisk(block, pindexConnect, chainparams.GetConsensus()))
+                    return AbortNode(state, "Failed to read block");
+                pconnectBlock = &block;
+            } else {
+                pconnectBlock = pblock;
+            }
+
+            if (!ConnectTip(state, chainparams, pindexConnect, pconnectBlock)) {
                 if (state.IsInvalid()) {
                     // The block violates a consensus rule.
                     if (!state.CorruptionPossible())

From db65d92df4096f278b8a6d9a6375a52e5a1f5cc2 Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@electriccoin.co>
Date: Mon, 6 Apr 2020 14:48:25 -0600
Subject: [PATCH 2/3] Make condition closer to original, Fix incorrect comment.

---
 src/main.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 4855e29f2..7fe9aa2d7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3213,7 +3213,6 @@ uint64_t nNotifiedSequence = 0;
 bool static ConnectTip(CValidationState& state, const CChainParams& chainparams, CBlockIndex* pindexNew, const CBlock* pblock)
 {
     assert(pblock && pindexNew->pprev == chainActive.Tip());
-    // Read block from disk.
     int64_t nTime1 = GetTimeMicros();
     // Apply the block atomically to the chain state.
     int64_t nTime2 = GetTimeMicros(); nTimeReadFromDisk += nTime2 - nTime1;
@@ -3425,14 +3424,15 @@ static bool ActivateBestChainStep(CValidationState& state, const CChainParams& c
 
         // Connect new blocks.
         BOOST_REVERSE_FOREACH(CBlockIndex *pindexConnect, vpindexToConnect) {
-            const CBlock* pconnectBlock = pblock;
+            const CBlock* pconnectBlock;
             CBlock block;
-            if (pindexConnect != pindexMostWork) {
+            if (pindexConnect == pindexMostWork) {
+                pconnectBlock = pblock;
+            } else {
+                // read the block to be connected from disk
                 if (!ReadBlockFromDisk(block, pindexConnect, chainparams.GetConsensus()))
                     return AbortNode(state, "Failed to read block");
                 pconnectBlock = &block;
-            } else {
-                pconnectBlock = pblock;
             }
 
             if (!ConnectTip(state, chainparams, pindexConnect, pconnectBlock)) {

From 368a7c5a9d39b9d2ac1c3f15dace53ec3b7691aa Mon Sep 17 00:00:00 2001
From: Kris Nuttycombe <kris@electriccoin.co>
Date: Wed, 22 Apr 2020 12:28:13 -0600
Subject: [PATCH 3/3] Ensure that we don't pass a null block pointer to
 ConnectTip.

---
 src/main.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.cpp b/src/main.cpp
index 7fe9aa2d7..df2dfd537 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -3426,7 +3426,7 @@ static bool ActivateBestChainStep(CValidationState& state, const CChainParams& c
         BOOST_REVERSE_FOREACH(CBlockIndex *pindexConnect, vpindexToConnect) {
             const CBlock* pconnectBlock;
             CBlock block;
-            if (pindexConnect == pindexMostWork) {
+            if (pblock && pindexConnect == pindexMostWork) {
                 pconnectBlock = pblock;
             } else {
                 // read the block to be connected from disk