Merge bitcoin/bitcoin#21866: [Bundle 7/7] validation: Farewell, global Chainstate!

6f994882de validation: Farewell, global Chainstate! (Carl Dong)
972c5166ee qt/test: Reset chainman in ~ChainstateManager instead (Carl Dong)
6c3b5dc0c1 scripted-diff: tree-wide: Remove all review-only assertions (Carl Dong)
3e82abb8dd tree-wide: Remove stray review-only assertion (Carl Dong)
f323248aba qt/test: Use existing chainman in ::TestGUI (can be scripted-diff) (Carl Dong)
6c15de129c scripted-diff: wallet/test: Use existing chainman (Carl Dong)
ee0ab1e959 fuzz: Initialize a TestingSetup for test_one_input (Carl Dong)
0d61634c06 scripted-diff: test: Use existing chainman in unit tests (Carl Dong)
e197076219 test: Pass in CoinsTip to ValidateCheckInputsForAllFlags (Carl Dong)
4d99b61014 test/miner_tests: Pass in chain tip to CreateBlockIndex (Carl Dong)
f0dd5e6bb4 test/util: Use existing chainman in ::PrepareBlock (Carl Dong)
464c313e30 init: Use existing chainman (Carl Dong)

Pull request description:

  Based on:  #21767

  à la Mr. Sandman
  ```
  Mr. Chainman, bring me a tip (bung, bung, bung, bung)
  Make it the most work that I've ever seen (bung, bung, bung, bung)
  Rewind old tip till we're at the fork point (bung, bung, bung, bung)
  Then tell it that it's time to call Con-nectTip

  Chainman, I'm so alone (bung, bung, bung, bung)
  No local objects to call my own (bung, bung, bung, bung)
  Please make sure I have a ref
  Mr. Chainman, bring me a tip!
  ```

  This is the last bundle in the #20158 series. Thanks everyone for their diligent review.
  I would like to call attention to https://github.com/bitcoin/bitcoin/issues/21766, where a few leftover improvements were collated.

  - Remove globals:
    - `ChainstateManager g_chainman`
    - `CChainState& ChainstateActive()`
    - `CChain& ChainActive()`
  - Remove all review-only assertions.

ACKs for top commit:
  jamesob:
    reACK 6f994882de based on the contents of
  ariard:
    Code Review ACK 6f99488.
  jnewbery:
    utACK 6f994882de
  achow101:
    Code Review ACK 6f994882de
  ryanofsky:
    Code review ACK 6f994882de.

Tree-SHA512: 4052ea79360cf0efd81ad0ee3f982e1d93aab1837dcec75f875a56ceda085de078bb3099a2137935d7cc2222004ad88da94b605ef5efef35cb6bc733725debe6

src/test/util/setup_common.cpp

@@ -146,7 +146,7 @@ ChainTestingSetup::ChainTestingSetup(const std::string& chainName, const std::ve
     m_node.fee_estimator = std::make_unique<CBlockPolicyEstimator>();
     m_node.mempool = std::make_unique<CTxMemPool>(m_node.fee_estimator.get(), 1);
 
-    m_node.chainman = &::g_chainman;
+    m_node.chainman = std::make_unique<ChainstateManager>();
 
     // Start script-checking threads. Set g_parallel_script_checks to true so they are used.
     constexpr int script_check_threads = 2;
@@ -168,7 +168,7 @@ ChainTestingSetup::~ChainTestingSetup()
     m_node.mempool.reset();
     m_node.scheduler.reset();
     m_node.chainman->Reset();
-    m_node.chainman = nullptr;
+    m_node.chainman.reset();
     pblocktree.reset();
 }
 
@@ -181,17 +181,17 @@ TestingSetup::TestingSetup(const std::string& chainName, const std::vector<const
     RegisterAllCoreRPCCommands(tableRPC);
 
     m_node.chainman->InitializeChainstate(*m_node.mempool);
-    ::ChainstateActive().InitCoinsDB(
+    m_node.chainman->ActiveChainstate().InitCoinsDB(
         /* cache_size_bytes */ 1 << 23, /* in_memory */ true, /* should_wipe */ false);
-    assert(!::ChainstateActive().CanFlushToDisk());
-    ::ChainstateActive().InitCoinsCache(1 << 23);
-    assert(::ChainstateActive().CanFlushToDisk());
-    if (!::ChainstateActive().LoadGenesisBlock(chainparams)) {
+    assert(!m_node.chainman->ActiveChainstate().CanFlushToDisk());
+    m_node.chainman->ActiveChainstate().InitCoinsCache(1 << 23);
+    assert(m_node.chainman->ActiveChainstate().CanFlushToDisk());
+    if (!m_node.chainman->ActiveChainstate().LoadGenesisBlock(chainparams)) {
         throw std::runtime_error("LoadGenesisBlock failed.");
     }
 
     BlockValidationState state;
-    if (!::ChainstateActive().ActivateBestChain(state, chainparams)) {
+    if (!m_node.chainman->ActiveChainstate().ActivateBestChain(state, chainparams)) {
         throw std::runtime_error(strprintf("ActivateBestChain failed. (%s)", state.ToString()));
     }
 
@@ -241,7 +241,7 @@ CBlock TestChain100Setup::CreateAndProcessBlock(const std::vector<CMutableTransa
 {
     const CChainParams& chainparams = Params();
     CTxMemPool empty_pool;
-    CBlock block = BlockAssembler(::ChainstateActive(), empty_pool, chainparams).CreateNewBlock(scriptPubKey)->block;
+    CBlock block = BlockAssembler(m_node.chainman->ActiveChainstate(), empty_pool, chainparams).CreateNewBlock(scriptPubKey)->block;
 
     Assert(block.vtx.size() == 1);
     for (const CMutableTransaction& tx : txns) {
@@ -300,7 +300,7 @@ CMutableTransaction TestChain100Setup::CreateValidMempoolTransaction(CTransactio
     // If submit=true, add transaction to the mempool.
     if (submit) {
         LOCK(cs_main);
-        const MempoolAcceptResult result = AcceptToMemoryPool(::ChainstateActive(), *m_node.mempool.get(), MakeTransactionRef(mempool_txn), /* bypass_limits */ false);
+        const MempoolAcceptResult result = AcceptToMemoryPool(m_node.chainman->ActiveChainstate(), *m_node.mempool.get(), MakeTransactionRef(mempool_txn), /* bypass_limits */ false);
         assert(result.m_result_type == MempoolAcceptResult::ResultType::VALID);
     }