From 9f6bb539359b98d5b39482ab8a28a68608f0c645 Mon Sep 17 00:00:00 2001
From: James O'Beirne <james.obeirne@pm.me>
Date: Sat, 12 Jun 2021 10:52:40 -0400
Subject: [PATCH] validation: add chainman ref to CChainState

Add an upwards reference to chainstate instances to the owning
ChainstateManager. This is necessary because there are a number
of `this_chainstate == chainman.ActiveChainstate()` checks that
will happen (as a result of assumeutxo) in functions that otherwise
don't have an easily-accessible reference to the chainstate's
ChainManager.
---
 src/test/validation_flush_tests.cpp |  4 ++--
 src/validation.cpp                  | 14 ++++++++++----
 src/validation.h                    |  6 ++++++
 3 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/src/test/validation_flush_tests.cpp b/src/test/validation_flush_tests.cpp
index 22aafcaa6c..9136c497ea 100644
--- a/src/test/validation_flush_tests.cpp
+++ b/src/test/validation_flush_tests.cpp
@@ -9,7 +9,7 @@
 
 #include <boost/test/unit_test.hpp>
 
-BOOST_FIXTURE_TEST_SUITE(validation_flush_tests, BasicTestingSetup)
+BOOST_FIXTURE_TEST_SUITE(validation_flush_tests, ChainTestingSetup)
 
 //! Test utilities for detecting when we need to flush the coins cache based
 //! on estimated memory usage.
@@ -20,7 +20,7 @@ BOOST_AUTO_TEST_CASE(getcoinscachesizestate)
 {
     CTxMemPool mempool;
     BlockManager blockman{};
-    CChainState chainstate{&mempool, blockman};
+    CChainState chainstate{&mempool, blockman, *Assert(m_node.chainman)};
     chainstate.InitCoinsDB(/*cache_size_bytes*/ 1 << 10, /*in_memory*/ true, /*should_wipe*/ false);
     WITH_LOCK(::cs_main, chainstate.InitCoinsCache(1 << 10));
 
diff --git a/src/validation.cpp b/src/validation.cpp
index 26333d7026..756e2ba905 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1209,10 +1209,15 @@ void CoinsViews::InitCache()
     m_cacheview = std::make_unique<CCoinsViewCache>(&m_catcherview);
 }
 
-CChainState::CChainState(CTxMemPool* mempool, BlockManager& blockman, std::optional<uint256> from_snapshot_blockhash)
+CChainState::CChainState(
+    CTxMemPool* mempool,
+    BlockManager& blockman,
+    ChainstateManager& chainman,
+    std::optional<uint256> from_snapshot_blockhash)
     : m_mempool(mempool),
       m_params(::Params()),
       m_blockman(blockman),
+      m_chainman(chainman),
       m_from_snapshot_blockhash(from_snapshot_blockhash) {}
 
 void CChainState::InitCoinsDB(
@@ -4699,7 +4704,7 @@ CChainState& ChainstateManager::InitializeChainstate(
     if (to_modify) {
         throw std::logic_error("should not be overwriting a chainstate");
     }
-    to_modify.reset(new CChainState(mempool, m_blockman, snapshot_blockhash));
+    to_modify.reset(new CChainState(mempool, m_blockman, *this, snapshot_blockhash));
 
     // Snapshot chainstates and initial IBD chaintates always become active.
     if (is_snapshot || (!is_snapshot && !m_active_chainstate)) {
@@ -4768,8 +4773,9 @@ bool ChainstateManager::ActivateSnapshot(
             static_cast<size_t>(current_coinsdb_cache_size * IBD_CACHE_PERC));
     }
 
-    auto snapshot_chainstate = WITH_LOCK(::cs_main, return std::make_unique<CChainState>(
-        /* mempool */ nullptr, m_blockman, base_blockhash));
+    auto snapshot_chainstate = WITH_LOCK(::cs_main,
+        return std::make_unique<CChainState>(
+            /* mempool */ nullptr, m_blockman, *this, base_blockhash));
 
     {
         LOCK(::cs_main);
diff --git a/src/validation.h b/src/validation.h
index 9a2be3ad97..b024699fe8 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -601,9 +601,15 @@ public:
     //! CChainState instances.
     BlockManager& m_blockman;
 
+    //! The chainstate manager that owns this chainstate. The reference is
+    //! necessary so that this instance can check whether it is the active
+    //! chainstate within deeply nested method calls.
+    ChainstateManager& m_chainman;
+
     explicit CChainState(
         CTxMemPool* mempool,
         BlockManager& blockman,
+        ChainstateManager& chainman,
         std::optional<uint256> from_snapshot_blockhash = std::nullopt);
 
     /**