From 4744efc9bae8b22efb76152a3c045d054c880399 Mon Sep 17 00:00:00 2001
From: Carl Dong <contact@carldong.me>
Date: Wed, 9 Sep 2020 16:05:39 -0400
Subject: [PATCH] validation: Pass in chainstate to CTxMemPool::check

This is the only instance where validation reaches for something outside
of it.
---
 src/net_processing.cpp |  4 ++--
 src/txmempool.cpp      | 11 +++++++----
 src/txmempool.h        |  2 +-
 src/validation.cpp     |  2 +-
 4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/src/net_processing.cpp b/src/net_processing.cpp
index c97f7ced463..429e0b5e899 100644
--- a/src/net_processing.cpp
+++ b/src/net_processing.cpp
@@ -2301,7 +2301,7 @@ void PeerManagerImpl::ProcessOrphanTx(std::set<uint256>& orphan_work_set)
             break;
         }
     }
-    m_mempool.check(&::ChainstateActive().CoinsTip());
+    m_mempool.check(m_chainman.ActiveChainstate());
 }
 
 /**
@@ -3262,7 +3262,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
         const TxValidationState& state = result.m_state;
 
         if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
-            m_mempool.check(&::ChainstateActive().CoinsTip());
+            m_mempool.check(m_chainman.ActiveChainstate());
             // As this version of the transaction was acceptable, we can forget about any
             // requests for it.
             m_txrequest.ForgetTxHash(tx.GetHash());
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index 899835019a7..05902a55c3e 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -619,7 +619,7 @@ static void CheckInputsAndUpdateCoins(const CTransaction& tx, CCoinsViewCache& m
     UpdateCoins(tx, mempoolDuplicate, std::numeric_limits<int>::max());
 }
 
-void CTxMemPool::check(const CCoinsViewCache *pcoins) const
+void CTxMemPool::check(CChainState& active_chainstate) const
 {
     if (m_check_ratio == 0) return;
 
@@ -633,8 +633,11 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
     CAmount check_total_fee{0};
     uint64_t innerUsage = 0;
 
-    CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache*>(pcoins));
-    const int64_t spendheight = g_chainman.m_blockman.GetSpendHeight(mempoolDuplicate);
+    CCoinsViewCache& active_coins_tip = active_chainstate.CoinsTip();
+    assert(std::addressof(::ChainstateActive().CoinsTip()) == std::addressof(active_coins_tip)); // TODO: REVIEW-ONLY, REMOVE IN FUTURE COMMIT
+    CCoinsViewCache mempoolDuplicate(const_cast<CCoinsViewCache*>(&active_coins_tip));
+    const int64_t spendheight = active_chainstate.m_chain.Height() + 1;
+    assert(g_chainman.m_blockman.GetSpendHeight(mempoolDuplicate) == spendheight); // TODO: REVIEW-ONLY, REMOVE IN FUTURE COMMIT
 
     std::list<const CTxMemPoolEntry*> waitingOnDependants;
     for (indexed_transaction_set::const_iterator it = mapTx.begin(); it != mapTx.end(); it++) {
@@ -655,7 +658,7 @@ void CTxMemPool::check(const CCoinsViewCache *pcoins) const
                 fDependsWait = true;
                 setParentCheck.insert(*it2);
             } else {
-                assert(pcoins->HaveCoin(txin.prevout));
+                assert(active_coins_tip.HaveCoin(txin.prevout));
             }
             // Check whether its inputs are marked in mapNextTx.
             auto it3 = mapNextTx.find(txin.prevout);
diff --git a/src/txmempool.h b/src/txmempool.h
index b8de326737a..001d856e432 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -604,7 +604,7 @@ public:
      * all inputs are in the mapNextTx array). If sanity-checking is turned off,
      * check does nothing.
      */
-    void check(const CCoinsViewCache *pcoins) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
+    void check(CChainState& active_chainstate) const EXCLUSIVE_LOCKS_REQUIRED(::cs_main);
 
     // addUnchecked must updated state for all ancestors of a given transaction,
     // to track size/count of descendant transactions.  First version of
diff --git a/src/validation.cpp b/src/validation.cpp
index eb6ce32b06e..8864c7f2488 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -2799,7 +2799,7 @@ bool CChainState::ActivateBestChainStep(BlockValidationState& state, const CChai
         // any disconnected transactions back to the mempool.
         UpdateMempoolForReorg(::ChainstateActive(), m_mempool, disconnectpool, true);
     }
-    m_mempool.check(&CoinsTip());
+    m_mempool.check(*this);
 
     CheckForkWarningConditions();