Merge bitcoin/bitcoin#21767: [Bundle 6/n] Prune g_chainman usage in auxiliary modules

7a799c9c2b8652e780d1fd5e1bf7d05b026c1c1a index: refactor-only: Reuse CChain ref (Carl Dong)
db33cde80fff749c6adff9e91fca5f27f4bb6278 index: Add chainstate member to BaseIndex (Carl Dong)
f4a47a1febfa35ab077f2a841fe31a8cd9618250 bench: Use existing chainman in AssembleBlock (Carl Dong)
91226eb91769aad5a63bc671595e1353a2b2247a bench: Use existing NodeContext in DuplicateInputs (Carl Dong)
e6b4aa6eb53dc555ecab2922af35e7a2572faf4f miner: Pass in chainman to RegenerateCommitments (Carl Dong)
9ecade14252ad1972f668d2d2e4ef44fdfcb944a rest: Add GetChainman function and use it (Carl Dong)
fc1c282845f6b8436d1ea4c68eb3511034c29bea rpc/blockchain: Use existing blockman in gettxoutsetinfo (Carl Dong)

Pull request description:

  Overall PR: #20158 (tree-wide: De-globalize ChainstateManager)

  The first 2 commits are fixups addressing review for the last bundle: #21391

  NEW note:
  1. I have opened #21766 which keeps track of potential improvements where the flaws already existed before the de-globalization work, please post on that issue about these improvements, thanks!

  Note to reviewers:
  1. This bundle may _apparently_ introduce usage of `g_chainman` or `::Chain(state|)Active()` globals, but these are resolved later on in the overall PR. [Commits of overall PR](https://github.com/bitcoin/bitcoin/pull/20158/commits)
  2. There may be seemingly obvious local references to `ChainstateManager` or other validation objects which are not being used in callers of the current function in question, this is done intentionally to **_keep each commit centered around one function/method_** to ease review and to make the overall change systematic. We don't assume anything about our callers. Rest assured that once we are considering that particular caller in later commits, we will use the obvious local references. [Commits of overall PR](https://github.com/bitcoin/bitcoin/pull/20158/commits)
  3. When changing a function/method that has many callers (e.g. `LookupBlockIndex` with 55 callers), it is sometimes easier (and less error-prone) to use a scripted-diff. When doing so, there will be 3 commits in sequence so that every commit compiles like so:
  1. Add `new_function`, make `old_function` a wrapper of `new_function`, divert all calls to `old_function` to `new_function` **in the local module only**
  2. Scripted-diff to divert all calls to `old_function` to `new_function` **in the rest of the codebase**
  3. Remove `old_function`

ACKs for top commit:
  jarolrod:
    ACK  7a799c9
  ariard:
    Code Review ACK 7a799c9
  fjahr:
    re-ACK 7a799c9c2b8652e780d1fd5e1bf7d05b026c1c1a
  MarcoFalke:
    review ACK 7a799c9c2b8652e780d1fd5e1bf7d05b026c1c1a 🌠
  ryanofsky:
    Code review ACK 7a799c9c2b8652e780d1fd5e1bf7d05b026c1c1a. Basically no change since last review except fixed rebase conflicts and a new comment about REST Ensure()
  jamesob:
    conditional ACK 7a799c9c2b8652e780d1fd5e1bf7d05b026c1c1a ([`jamesob/ackr/21767.1.dongcarl.bundle_6_n_prune_g_chai`](https://github.com/jamesob/bitcoin/tree/ackr/21767.1.dongcarl.bundle_6_n_prune_g_chai))

Tree-SHA512: 531c00ddcb318817457db2812d9a9d930bc664e58e6f7f1c746350732b031dd624270bfa6b9f49d8056aeb6321d973f0e38e4ff914acd6768edd8602c017d10e

4 files changed, 25 insertions, 20 deletions

diff --git a/src/index/base.cpp b/src/index/base.cpp
index 4079fc4569..3a61af28b7 100644
--- a/src/index/base.cpp
+++ b/src/index/base.cpp
@@ -60,33 +60,34 @@ bool BaseIndex::Init()
     }
 
     LOCK(cs_main);
+    CChain& active_chain = m_chainstate->m_chain;
     if (locator.IsNull()) {
         m_best_block_index = nullptr;
     } else {
-        m_best_block_index = g_chainman.m_blockman.FindForkInGlobalIndex(::ChainActive(), locator);
+        m_best_block_index = m_chainstate->m_blockman.FindForkInGlobalIndex(active_chain, locator);
     }
-    m_synced = m_best_block_index.load() == ::ChainActive().Tip();
+    m_synced = m_best_block_index.load() == active_chain.Tip();
     if (!m_synced) {
         bool prune_violation = false;
         if (!m_best_block_index) {
             // index is not built yet
             // make sure we have all block data back to the genesis
-            const CBlockIndex* block = ::ChainActive().Tip();
+            const CBlockIndex* block = active_chain.Tip();
             while (block->pprev && (block->pprev->nStatus & BLOCK_HAVE_DATA)) {
                 block = block->pprev;
             }
-            prune_violation = block != ::ChainActive().Genesis();
+            prune_violation = block != active_chain.Genesis();
         }
         // in case the index has a best block set and is not fully synced
         // check if we have the required blocks to continue building the index
         else {
             const CBlockIndex* block_to_test = m_best_block_index.load();
-            if (!ChainActive().Contains(block_to_test)) {
+            if (!active_chain.Contains(block_to_test)) {
                 // if the bestblock is not part of the mainchain, find the fork
                 // and make sure we have all data down to the fork
-                block_to_test = ::ChainActive().FindFork(block_to_test);
+                block_to_test = active_chain.FindFork(block_to_test);
             }
-            const CBlockIndex* block = ::ChainActive().Tip();
+            const CBlockIndex* block = active_chain.Tip();
             prune_violation = true;
             // check backwards from the tip if we have all block data until we reach the indexes bestblock
             while (block_to_test && block->pprev && (block->pprev->nStatus & BLOCK_HAVE_DATA)) {
@@ -104,20 +105,20 @@ bool BaseIndex::Init()
     return true;
 }
 
-static const CBlockIndex* NextSyncBlock(const CBlockIndex* pindex_prev) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
+static const CBlockIndex* NextSyncBlock(const CBlockIndex* pindex_prev, CChain& chain) EXCLUSIVE_LOCKS_REQUIRED(cs_main)
 {
     AssertLockHeld(cs_main);
 
     if (!pindex_prev) {
-        return ::ChainActive().Genesis();
+        return chain.Genesis();
     }
 
-    const CBlockIndex* pindex = ::ChainActive().Next(pindex_prev);
+    const CBlockIndex* pindex = chain.Next(pindex_prev);
     if (pindex) {
         return pindex;
     }
 
-    return ::ChainActive().Next(::ChainActive().FindFork(pindex_prev));
+    return chain.Next(chain.FindFork(pindex_prev));
 }
 
 void BaseIndex::ThreadSync()
@@ -140,7 +141,7 @@ void BaseIndex::ThreadSync()
 
             {
                 LOCK(cs_main);
-                const CBlockIndex* pindex_next = NextSyncBlock(pindex);
+                const CBlockIndex* pindex_next = NextSyncBlock(pindex, m_chainstate->m_chain);
                 if (!pindex_next) {
                     m_best_block_index = pindex;
                     m_synced = true;
@@ -203,7 +204,7 @@ bool BaseIndex::Commit()
 bool BaseIndex::CommitInternal(CDBBatch& batch)
 {
     LOCK(cs_main);
-    GetDB().WriteBestBlock(batch, ::ChainActive().GetLocator(m_best_block_index));
+    GetDB().WriteBestBlock(batch, m_chainstate->m_chain.GetLocator(m_best_block_index));
     return true;
 }
 
@@ -279,7 +280,7 @@ void BaseIndex::ChainStateFlushed(const CBlockLocator& locator)
     const CBlockIndex* locator_tip_index;
     {
         LOCK(cs_main);
-        locator_tip_index = g_chainman.m_blockman.LookupBlockIndex(locator_tip_hash);
+        locator_tip_index = m_chainstate->m_blockman.LookupBlockIndex(locator_tip_hash);
     }
 
     if (!locator_tip_index) {
@@ -320,7 +321,7 @@ bool BaseIndex::BlockUntilSyncedToCurrentChain() const
         // Skip the queue-draining stuff if we know we're caught up with
         // ::ChainActive().Tip().
         LOCK(cs_main);
-        const CBlockIndex* chain_tip = ::ChainActive().Tip();
+        const CBlockIndex* chain_tip = m_chainstate->m_chain.Tip();
         const CBlockIndex* best_block_index = m_best_block_index.load();
         if (best_block_index->GetAncestor(chain_tip->nHeight) == chain_tip) {
             return true;
@@ -337,8 +338,10 @@ void BaseIndex::Interrupt()
     m_interrupt();
 }
 
-bool BaseIndex::Start()
+bool BaseIndex::Start(CChainState& active_chainstate)
 {
+    assert(std::addressof(::ChainstateActive()) == std::addressof(active_chainstate));
+    m_chainstate = &active_chainstate;
     // Need to register this ValidationInterface before running Init(), so that
     // callbacks are not missed if Init sets m_synced to true.
     RegisterValidationInterface(this);
diff --git a/src/index/base.h b/src/index/base.h
index 59eefab29e..df4bdff1ea 100644
--- a/src/index/base.h
+++ b/src/index/base.h
@@ -12,6 +12,7 @@
 #include <validationinterface.h>
 
 class CBlockIndex;
+class CChainState;
 
 struct IndexSummary {
     std::string name;
@@ -75,8 +76,9 @@ private:
     /// to a chain reorganization), the index must halt until Commit succeeds or else it could end up
     /// getting corrupted.
     bool Commit();
-
 protected:
+    CChainState* m_chainstate{nullptr};
+
     void BlockConnected(const std::shared_ptr<const CBlock>& block, const CBlockIndex* pindex) override;
 
     void ChainStateFlushed(const CBlockLocator& locator) override;
@@ -117,7 +119,7 @@ public:
 
     /// Start initializes the sync state and registers the instance as a
     /// ValidationInterface so that it stays in sync with blockchain updates.
-    [[nodiscard]] bool Start();
+    [[nodiscard]] bool Start(CChainState& active_chainstate);
 
     /// Stops the instance from staying in sync with blockchain updates.
     void Stop();
diff --git a/src/index/coinstatsindex.cpp b/src/index/coinstatsindex.cpp
index e046527283..8c6046489b 100644
--- a/src/index/coinstatsindex.cpp
+++ b/src/index/coinstatsindex.cpp
@@ -266,7 +266,7 @@ bool CoinStatsIndex::Rewind(const CBlockIndex* current_tip, const CBlockIndex* n
 
     {
         LOCK(cs_main);
-        CBlockIndex* iter_tip{g_chainman.m_blockman.LookupBlockIndex(current_tip->GetBlockHash())};
+        CBlockIndex* iter_tip{m_chainstate->m_blockman.LookupBlockIndex(current_tip->GetBlockHash())};
         const auto& consensus_params{Params().GetConsensus()};
 
         do {
diff --git a/src/index/txindex.cpp b/src/index/txindex.cpp
index d9e437ad10..782e557478 100644
--- a/src/index/txindex.cpp
+++ b/src/index/txindex.cpp
@@ -204,7 +204,7 @@ bool TxIndex::Init()
     // Attempt to migrate txindex from the old database to the new one. Even if
     // chain_tip is null, the node could be reindexing and we still want to
     // delete txindex records in the old database.
-    if (!m_db->MigrateData(*pblocktree, ::ChainActive().GetLocator())) {
+    if (!m_db->MigrateData(*pblocktree, m_chainstate->m_chain.GetLocator())) {
         return false;
     }