rpc: Tidy up local references (see commit message)

Organize local variables/references such that:

1. There is always a `ChainstateManager` reference before any `LOCK(cs_main)`.
2. NodeContext references are used with Ensure*() functions introduced in
   previous commit where appropriate to avoid duplicate assertions.

4 files changed, 64 insertions, 43 deletions

diff --git a/src/rest.cpp b/src/rest.cpp
index dd2d649ff4..eea0d67882 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -180,8 +180,8 @@ static bool rest_headers(const std::any& context,
     std::vector<const CBlockIndex *> headers;
     headers.reserve(count);
     {
-        LOCK(cs_main);
         ChainstateManager& chainman = EnsureAnyChainman(context);
+        LOCK(cs_main);
         tip = chainman.ActiveChain().Tip();
         const CBlockIndex* pindex = chainman.m_blockman.LookupBlockIndex(hash);
         while (pindex != nullptr && chainman.ActiveChain().Contains(pindex)) {
@@ -250,8 +250,8 @@ static bool rest_block(const std::any& context,
     CBlockIndex* pblockindex = nullptr;
     CBlockIndex* tip = nullptr;
     {
-        LOCK(cs_main);
         ChainstateManager& chainman = EnsureAnyChainman(context);
+        LOCK(cs_main);
         tip = chainman.ActiveChain().Tip();
         pblockindex = chainman.m_blockman.LookupBlockIndex(hash);
         if (!pblockindex) {
@@ -641,8 +641,9 @@ static bool rest_blockhash_by_height(const std::any& context, HTTPRequest* req,
 
     CBlockIndex* pblockindex = nullptr;
     {
+        ChainstateManager& chainman = EnsureAnyChainman(context);
         LOCK(cs_main);
-        const CChain& active_chain = EnsureAnyChainman(context).ActiveChain();
+        const CChain& active_chain = chainman.ActiveChain();
         if (blockheight > active_chain.Height()) {
             return RESTERR(req, HTTP_NOT_FOUND, "Block height out of range");
         }
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 19df2d8031..5fd1521e73 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -210,8 +210,9 @@ static RPCHelpMan getblockcount()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    return EnsureAnyChainman(request.context).ActiveChain().Height();
+    return chainman.ActiveChain().Height();
 },
     };
 }
@@ -229,8 +230,9 @@ static RPCHelpMan getbestblockhash()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    return EnsureAnyChainman(request.context).ActiveChain().Tip()->GetBlockHash().GetHex();
+    return chainman.ActiveChain().Tip()->GetBlockHash().GetHex();
 },
     };
 }
@@ -410,8 +412,9 @@ static RPCHelpMan getdifficulty()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    return GetDifficulty(EnsureAnyChainman(request.context).ActiveChain().Tip());
+    return GetDifficulty(chainman.ActiveChain().Tip());
 },
     };
 }
@@ -775,8 +778,9 @@ static RPCHelpMan getblockhash()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    const CChain& active_chain = EnsureAnyChainman(request.context).ActiveChain();
+    const CChain& active_chain = chainman.ActiveChain();
 
     int nHeight = request.params[0].get_int();
     if (nHeight < 0 || nHeight > active_chain.Height())
@@ -835,8 +839,8 @@ static RPCHelpMan getblockheader()
     const CBlockIndex* pblockindex;
     const CBlockIndex* tip;
     {
-        LOCK(cs_main);
         ChainstateManager& chainman = EnsureAnyChainman(request.context);
+        LOCK(cs_main);
         pblockindex = chainman.m_blockman.LookupBlockIndex(hash);
         tip = chainman.ActiveChain().Tip();
     }
@@ -960,8 +964,8 @@ static RPCHelpMan getblock()
     const CBlockIndex* pblockindex;
     const CBlockIndex* tip;
     {
-        LOCK(cs_main);
         ChainstateManager& chainman = EnsureAnyChainman(request.context);
+        LOCK(cs_main);
         pblockindex = chainman.m_blockman.LookupBlockIndex(hash);
         tip = chainman.ActiveChain().Tip();
 
@@ -1003,8 +1007,8 @@ static RPCHelpMan pruneblockchain()
     if (!fPruneMode)
         throw JSONRPCError(RPC_MISC_ERROR, "Cannot prune blocks because node is not in prune mode.");
 
-    LOCK(cs_main);
     ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    LOCK(cs_main);
 
     int heightParam = request.params[0].get_int();
     if (heightParam < 0)
@@ -1086,7 +1090,9 @@ static RPCHelpMan gettxoutsetinfo()
     UniValue ret(UniValue::VOBJ);
 
     CCoinsStats stats;
-    CChainState& active_chainstate = EnsureAnyChainman(request.context).ActiveChainstate();
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    ChainstateManager& chainman = EnsureChainman(node);
+    CChainState& active_chainstate = chainman.ActiveChainstate();
     active_chainstate.ForceFlushStateToDisk();
 
     const CoinStatsHashType hash_type{request.params[0].isNull() ? CoinStatsHashType::HASH_SERIALIZED : ParseHashType(request.params[0].get_str())};
@@ -1098,7 +1104,6 @@ static RPCHelpMan gettxoutsetinfo()
         coins_view = &active_chainstate.CoinsDB();
         blockman = &active_chainstate.m_blockman;
     }
-    NodeContext& node = EnsureAnyNodeContext(request.context);
     if (GetUTXOStats(coins_view, *blockman, stats, hash_type, node.rpc_interruption_point)) {
         ret.pushKV("height", (int64_t)stats.nHeight);
         ret.pushKV("bestblock", stats.hashBlock.GetHex());
@@ -1158,6 +1163,8 @@ static RPCHelpMan gettxout()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    ChainstateManager& chainman = EnsureChainman(node);
     LOCK(cs_main);
 
     UniValue ret(UniValue::VOBJ);
@@ -1170,11 +1177,11 @@ static RPCHelpMan gettxout()
         fMempool = request.params[2].get_bool();
 
     Coin coin;
-    CChainState& active_chainstate = EnsureAnyChainman(request.context).ActiveChainstate();
+    CChainState& active_chainstate = chainman.ActiveChainstate();
     CCoinsViewCache* coins_view = &active_chainstate.CoinsTip();
 
     if (fMempool) {
-        const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
+        const CTxMemPool& mempool = EnsureMemPool(node);
         LOCK(mempool.cs);
         CCoinsViewMemPool view(coins_view, mempool);
         if (!view.GetCoin(out, coin) || mempool.isSpent(out)) {
@@ -1224,9 +1231,10 @@ static RPCHelpMan verifychain()
     const int check_level(request.params[0].isNull() ? DEFAULT_CHECKLEVEL : request.params[0].get_int());
     const int check_depth{request.params[1].isNull() ? DEFAULT_CHECKBLOCKS : request.params[1].get_int()};
 
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
 
-    CChainState& active_chainstate = EnsureAnyChainman(request.context).ActiveChainstate();
+    CChainState& active_chainstate = chainman.ActiveChainstate();
     return CVerifyDB().VerifyDB(Params(), active_chainstate, &active_chainstate.CoinsTip(), check_level, check_depth);
 },
     };
@@ -1353,8 +1361,8 @@ RPCHelpMan getblockchaininfo()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
-    LOCK(cs_main);
     ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    LOCK(cs_main);
 
     const CBlockIndex* tip = chainman.ActiveChain().Tip();
     CHECK_NONFATAL(tip);
@@ -1893,8 +1901,8 @@ static RPCHelpMan getblockstats()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
-    LOCK(cs_main);
     ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    LOCK(cs_main);
 
     CBlockIndex* pindex;
     if (request.params[0].isNum()) {
@@ -2295,16 +2303,16 @@ static RPCHelpMan scantxoutset()
         int64_t count = 0;
         std::unique_ptr<CCoinsViewCursor> pcursor;
         CBlockIndex* tip;
+        NodeContext& node = EnsureAnyNodeContext(request.context);
         {
+            ChainstateManager& chainman = EnsureChainman(node);
             LOCK(cs_main);
-            ChainstateManager& chainman = EnsureAnyChainman(request.context);
             chainman.ActiveChainstate().ForceFlushStateToDisk();
             pcursor = std::unique_ptr<CCoinsViewCursor>(chainman.ActiveChainstate().CoinsDB().Cursor());
             CHECK_NONFATAL(pcursor);
             tip = chainman.ActiveChain().Tip();
             CHECK_NONFATAL(tip);
         }
-        NodeContext& node = EnsureAnyNodeContext(request.context);
         bool res = FindScriptPubKey(g_scan_progress, g_should_abort_scan, count, pcursor.get(), needles, coins, node.rpc_interruption_point);
         result.pushKV("success", res);
         result.pushKV("txouts", count);
@@ -2377,8 +2385,9 @@ static RPCHelpMan getblockfilter()
     const CBlockIndex* block_index;
     bool block_was_connected;
     {
+        ChainstateManager& chainman = EnsureAnyChainman(request.context);
         LOCK(cs_main);
-        block_index = EnsureAnyChainman(request.context).m_blockman.LookupBlockIndex(block_hash);
+        block_index = chainman.m_blockman.LookupBlockIndex(block_hash);
         if (!block_index) {
             throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found");
         }
diff --git a/src/rpc/mining.cpp b/src/rpc/mining.cpp
index f72a19a8a1..37c87d7b01 100644
--- a/src/rpc/mining.cpp
+++ b/src/rpc/mining.cpp
@@ -100,9 +100,9 @@ static RPCHelpMan getnetworkhashps()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
-    const CChain& active_chain = EnsureAnyChainman(request.context).ActiveChain();
-    return GetNetworkHashPS(!request.params[0].isNull() ? request.params[0].get_int() : 120, !request.params[1].isNull() ? request.params[1].get_int() : -1, active_chain);
+    return GetNetworkHashPS(!request.params[0].isNull() ? request.params[0].get_int() : 120, !request.params[1].isNull() ? request.params[1].get_int() : -1, chainman.ActiveChain());
 },
     };
 }
@@ -235,8 +235,9 @@ static RPCHelpMan generatetodescriptor()
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, error);
     }
 
-    const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    const CTxMemPool& mempool = EnsureMemPool(node);
+    ChainstateManager& chainman = EnsureChainman(node);
 
     return generateBlocks(chainman, mempool, coinbase_script, num_blocks, max_tries);
 },
@@ -280,8 +281,9 @@ static RPCHelpMan generatetoaddress()
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Error: Invalid address");
     }
 
-    const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    const CTxMemPool& mempool = EnsureMemPool(node);
+    ChainstateManager& chainman = EnsureChainman(node);
 
     CScript coinbase_script = GetScriptForDestination(destination);
 
@@ -329,7 +331,8 @@ static RPCHelpMan generateblock()
         coinbase_script = GetScriptForDestination(destination);
     }
 
-    const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    const CTxMemPool& mempool = EnsureMemPool(node);
 
     std::vector<CTransactionRef> txs;
     const auto raw_txs_or_txids = request.params[1].get_array();
@@ -358,7 +361,7 @@ static RPCHelpMan generateblock()
     CChainParams chainparams(Params());
     CBlock block;
 
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    ChainstateManager& chainman = EnsureChainman(node);
     {
         LOCK(cs_main);
 
@@ -424,9 +427,11 @@ static RPCHelpMan getmininginfo()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    const CTxMemPool& mempool = EnsureMemPool(node);
+    ChainstateManager& chainman = EnsureChainman(node);
     LOCK(cs_main);
-    const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
-    const CChain& active_chain = EnsureAnyChainman(request.context).ActiveChain();
+    const CChain& active_chain = chainman.ActiveChain();
 
     UniValue obj(UniValue::VOBJ);
     obj.pushKV("blocks",           (int)active_chain.Height());
@@ -595,8 +600,9 @@ static RPCHelpMan getblocktemplate()
                 },
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+    ChainstateManager& chainman = EnsureChainman(node);
     LOCK(cs_main);
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
 
     std::string strMode = "template";
     UniValue lpval = NullUniValue;
@@ -663,7 +669,6 @@ static RPCHelpMan getblocktemplate()
     if (strMode != "template")
         throw JSONRPCError(RPC_INVALID_PARAMETER, "Invalid mode");
 
-    NodeContext& node = EnsureAnyNodeContext(request.context);
     if(!node.connman)
         throw JSONRPCError(RPC_CLIENT_P2P_DISABLED, "Error: Peer-to-peer functionality missing or disabled");
 
@@ -678,7 +683,7 @@ static RPCHelpMan getblocktemplate()
     }
 
     static unsigned int nTransactionsUpdatedLast;
-    const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
+    const CTxMemPool& mempool = EnsureMemPool(node);
 
     if (!lpval.isNull())
     {
diff --git a/src/rpc/rawtransaction.cpp b/src/rpc/rawtransaction.cpp
index 3e6edde41a..5947755819 100644
--- a/src/rpc/rawtransaction.cpp
+++ b/src/rpc/rawtransaction.cpp
@@ -158,7 +158,7 @@ static RPCHelpMan getrawtransaction()
         [&](const RPCHelpMan& self, const JSONRPCRequest& request) -> UniValue
 {
     const NodeContext& node = EnsureAnyNodeContext(request.context);
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
+    ChainstateManager& chainman = EnsureChainman(node);
 
     bool in_active_chain = true;
     uint256 hash = ParseHashV(request.params[0], "parameter 1");
@@ -350,9 +350,9 @@ static RPCHelpMan verifytxoutproof()
     if (merkleBlock.txn.ExtractMatches(vMatch, vIndex) != merkleBlock.header.hashMerkleRoot)
         return res;
 
+    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     LOCK(cs_main);
 
-    ChainstateManager& chainman = EnsureAnyChainman(request.context);
     const CBlockIndex* pindex = chainman.m_blockman.LookupBlockIndex(merkleBlock.header.GetHash());
     if (!pindex || !chainman.ActiveChain().Contains(pindex) || pindex->nTx == 0) {
         throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, "Block not found in chain");
@@ -678,10 +678,11 @@ static RPCHelpMan combinerawtransaction()
     CCoinsView viewDummy;
     CCoinsViewCache view(&viewDummy);
     {
-        const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
-        LOCK(cs_main);
-        LOCK(mempool.cs);
-        CCoinsViewCache &viewChain = EnsureAnyChainman(request.context).ActiveChainstate().CoinsTip();
+        NodeContext& node = EnsureAnyNodeContext(request.context);
+        const CTxMemPool& mempool = EnsureMemPool(node);
+        ChainstateManager& chainman = EnsureChainman(node);
+        LOCK2(cs_main, mempool.cs);
+        CCoinsViewCache &viewChain = chainman.ActiveChainstate().CoinsTip();
         CCoinsViewMemPool viewMempool(&viewChain, mempool);
         view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view
 
@@ -943,7 +944,9 @@ static RPCHelpMan testmempoolaccept()
                                              DEFAULT_MAX_RAW_TX_FEE_RATE :
                                              CFeeRate(AmountFromValue(request.params[1]));
 
-    CTxMemPool& mempool = EnsureAnyMemPool(request.context);
+    NodeContext& node = EnsureAnyNodeContext(request.context);
+
+    CTxMemPool& mempool = EnsureMemPool(node);
     int64_t virtual_size = GetVirtualTransactionSize(*tx);
     CAmount max_raw_tx_fee = max_raw_tx_fee_rate.GetFee(virtual_size);
 
@@ -952,7 +955,8 @@ static RPCHelpMan testmempoolaccept()
     result_0.pushKV("txid", tx->GetHash().GetHex());
     result_0.pushKV("wtxid", tx->GetWitnessHash().GetHex());
 
-    const MempoolAcceptResult accept_result = WITH_LOCK(cs_main, return AcceptToMemoryPool(EnsureAnyChainman(request.context).ActiveChainstate(), mempool, std::move(tx),
+    ChainstateManager& chainman = EnsureChainman(node);
+    const MempoolAcceptResult accept_result = WITH_LOCK(cs_main, return AcceptToMemoryPool(chainman.ActiveChainstate(), mempool, std::move(tx),
                                                   false /* bypass_limits */, /* test_accept */ true));
 
     // Only return the fee and vsize if the transaction would pass ATMP.
@@ -1601,9 +1605,11 @@ static RPCHelpMan utxoupdatepsbt()
     CCoinsView viewDummy;
     CCoinsViewCache view(&viewDummy);
     {
-        const CTxMemPool& mempool = EnsureAnyMemPool(request.context);
+        NodeContext& node = EnsureAnyNodeContext(request.context);
+        const CTxMemPool& mempool = EnsureMemPool(node);
+        ChainstateManager& chainman = EnsureChainman(node);
         LOCK2(cs_main, mempool.cs);
-        CCoinsViewCache &viewChain = EnsureAnyChainman(request.context).ActiveChainstate().CoinsTip();
+        CCoinsViewCache &viewChain = chainman.ActiveChainstate().CoinsTip();
         CCoinsViewMemPool viewMempool(&viewChain, mempool);
         view.SetBackend(viewMempool); // temporarily switch cache backend to db+mempool view