Merge #19413: refactor: Remove confusing BlockIndex global

fa0dfdf447d5b84a1849dc823d8508463600136a refactor: Remove confusing BlockIndex global (MarcoFalke)

Pull request description:

  The global `::BlockIndex()` is problematic for several reasons:

  * It returns a mutable reference to the block tree, without the appropriate lock annotation (`m_block_index` is guarded by `cs_main`). The current code is fine, but in the future this might lead to accidental races and data corruption.
  * The rpc server shouldn't rely on node globals, but rather a context that is passed in to the RPC method.
  * Tests might want to spin up their own block tree, and thus should also not rely on a single global.

  Fix all issues by removing the global

ACKs for top commit:
  promag:
    Code review ACK fa0dfdf447d5b84a1849dc823d8508463600136a.
  jonatack:
    re-ACK fa0dfdf

Tree-SHA512: 8f158fc5e1c67e73588a21c25677b3fa0fe442313b13ec24b87054806c59607d6ba0c062a865ce3e0ee568706bd0d1faa84febda21aff5bcd65dab172f74c52f

5 files changed, 22 insertions, 32 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 19f6e7d038..35e211a9d7 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -1588,7 +1588,7 @@ bool AppInitMain(const util::Ref& context, NodeContext& node)
 
                 // If the loaded chain has a wrong genesis, bail out immediately
                 // (we're likely using a testnet datadir, or the other way around).
-                if (!::BlockIndex().empty() &&
+                if (!chainman.BlockIndex().empty() &&
                         !LookupBlockIndex(chainparams.GetConsensus().hashGenesisBlock)) {
                     return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));
                 }
@@ -1868,8 +1868,8 @@ bool AppInitMain(const util::Ref& context, NodeContext& node)
     //// debug print
     {
         LOCK(cs_main);
-        LogPrintf("block tree size = %u\n", ::BlockIndex().size());
-        chain_active_height = ::ChainActive().Height();
+        LogPrintf("block tree size = %u\n", chainman.BlockIndex().size());
+        chain_active_height = chainman.ActiveChain().Height();
     }
     LogPrintf("nBestHeight = %d\n", chain_active_height);
 
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 64f8a5bb3b..6250ca918a 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -1325,50 +1325,48 @@ static UniValue getchaintips(const JSONRPCRequest& request)
                 },
             }.Check(request);
 
+    ChainstateManager& chainman = EnsureChainman(request.context);
     LOCK(cs_main);
 
     /*
-     * Idea:  the set of chain tips is ::ChainActive().tip, plus orphan blocks which do not have another orphan building off of them.
+     * Idea: The set of chain tips is the active chain tip, plus orphan blocks which do not have another orphan building off of them.
      * Algorithm:
      *  - Make one pass through BlockIndex(), picking out the orphan blocks, and also storing a set of the orphan block's pprev pointers.
      *  - Iterate through the orphan blocks. If the block isn't pointed to by another orphan, it is a chain tip.
-     *  - add ::ChainActive().Tip()
+     *  - Add the active chain tip
      */
     std::set<const CBlockIndex*, CompareBlocksByHeight> setTips;
     std::set<const CBlockIndex*> setOrphans;
     std::set<const CBlockIndex*> setPrevs;
 
-    for (const std::pair<const uint256, CBlockIndex*>& item : ::BlockIndex())
-    {
-        if (!::ChainActive().Contains(item.second)) {
+    for (const std::pair<const uint256, CBlockIndex*>& item : chainman.BlockIndex()) {
+        if (!chainman.ActiveChain().Contains(item.second)) {
             setOrphans.insert(item.second);
             setPrevs.insert(item.second->pprev);
         }
     }
 
-    for (std::set<const CBlockIndex*>::iterator it = setOrphans.begin(); it != setOrphans.end(); ++it)
-    {
+    for (std::set<const CBlockIndex*>::iterator it = setOrphans.begin(); it != setOrphans.end(); ++it) {
         if (setPrevs.erase(*it) == 0) {
             setTips.insert(*it);
         }
     }
 
     // Always report the currently active tip.
-    setTips.insert(::ChainActive().Tip());
+    setTips.insert(chainman.ActiveChain().Tip());
 
     /* Construct the output array.  */
     UniValue res(UniValue::VARR);
-    for (const CBlockIndex* block : setTips)
-    {
+    for (const CBlockIndex* block : setTips) {
         UniValue obj(UniValue::VOBJ);
         obj.pushKV("height", block->nHeight);
         obj.pushKV("hash", block->phashBlock->GetHex());
 
-        const int branchLen = block->nHeight - ::ChainActive().FindFork(block)->nHeight;
+        const int branchLen = block->nHeight - chainman.ActiveChain().FindFork(block)->nHeight;
         obj.pushKV("branchlen", branchLen);
 
         std::string status;
-        if (::ChainActive().Contains(block)) {
+        if (chainman.ActiveChain().Contains(block)) {
             // This block is part of the currently active chain.
             status = "active";
         } else if (block->nStatus & BLOCK_FAILED_MASK) {
diff --git a/src/validation.cpp b/src/validation.cpp
index e59dda429c..4871a631dc 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1321,12 +1321,6 @@ bool CChainState::IsInitialBlockDownload() const
 
 static CBlockIndex *pindexBestForkTip = nullptr, *pindexBestForkBase = nullptr;
 
-BlockMap& BlockIndex()
-{
-    LOCK(::cs_main);
-    return g_chainman.m_blockman.m_block_index;
-}
-
 static void AlertNotify(const std::string& strMessage)
 {
     uiInterface.NotifyAlertChanged();
diff --git a/src/validation.h b/src/validation.h
index 58383ad923..a148dacb7c 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -886,9 +886,6 @@ CChainState& ChainstateActive();
 /** Please prefer the identical ChainstateManager::ActiveChain */
 CChain& ChainActive();
 
-/** Please prefer the identical ChainstateManager::BlockIndex */
-BlockMap& BlockIndex();
-
 /** Global variable that points to the active block tree (protected by cs_main) */
 extern std::unique_ptr<CBlockTreeDB> pblocktree;
 
diff --git a/src/wallet/test/wallet_tests.cpp b/src/wallet/test/wallet_tests.cpp
index 497ccd14bb..4ecb1124b5 100644
--- a/src/wallet/test/wallet_tests.cpp
+++ b/src/wallet/test/wallet_tests.cpp
@@ -333,7 +333,7 @@ BOOST_FIXTURE_TEST_CASE(coin_mark_dirty_immature_credit, TestChain100Setup)
     BOOST_CHECK_EQUAL(wtx.GetImmatureCredit(), 50*COIN);
 }
 
-static int64_t AddTx(CWallet& wallet, uint32_t lockTime, int64_t mockTime, int64_t blockTime)
+static int64_t AddTx(ChainstateManager& chainman, CWallet& wallet, uint32_t lockTime, int64_t mockTime, int64_t blockTime)
 {
     CMutableTransaction tx;
     CWalletTx::Confirmation confirm;
@@ -341,7 +341,8 @@ static int64_t AddTx(CWallet& wallet, uint32_t lockTime, int64_t mockTime, int64
     SetMockTime(mockTime);
     CBlockIndex* block = nullptr;
     if (blockTime > 0) {
-        auto inserted = ::BlockIndex().emplace(GetRandHash(), new CBlockIndex);
+        LOCK(cs_main);
+        auto inserted = chainman.BlockIndex().emplace(GetRandHash(), new CBlockIndex);
         assert(inserted.second);
         const uint256& hash = inserted.first->first;
         block = inserted.first->second;
@@ -363,24 +364,24 @@ static int64_t AddTx(CWallet& wallet, uint32_t lockTime, int64_t mockTime, int64
 BOOST_AUTO_TEST_CASE(ComputeTimeSmart)
 {
     // New transaction should use clock time if lower than block time.
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 1, 100, 120), 100);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 1, 100, 120), 100);
 
     // Test that updating existing transaction does not change smart time.
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 1, 200, 220), 100);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 1, 200, 220), 100);
 
     // New transaction should use clock time if there's no block time.
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 2, 300, 0), 300);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 2, 300, 0), 300);
 
     // New transaction should use block time if lower than clock time.
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 3, 420, 400), 400);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 3, 420, 400), 400);
 
     // New transaction should use latest entry time if higher than
     // min(block time, clock time).
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 4, 500, 390), 400);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 4, 500, 390), 400);
 
     // If there are future entries, new transaction should use time of the
     // newest entry that is no more than 300 seconds ahead of the clock time.
-    BOOST_CHECK_EQUAL(AddTx(m_wallet, 5, 50, 600), 300);
+    BOOST_CHECK_EQUAL(AddTx(*m_node.chainman, m_wallet, 5, 50, 600), 300);
 
     // Reset mock time for other tests.
     SetMockTime(0);