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

1 files changed, 10 insertions, 12 deletions

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) {