Merge #21062: refactor: return MempoolAcceptResult from ATMP

53e716e [refactor] improve style for touched code (gzhao408)
174cb53 [refactor] const ATMPArgs and non-const Workspace (gzhao408)
f82baf0 [refactor] return MempoolAcceptResult (gzhao408)
9db10a5 [refactor] clean up logic in testmempoolaccept (gzhao408)

Pull request description:

  This is the first 4 commits of #20833, and does refactoring only. It should be relatively simple to review, and offers a few nice things:
  - It makes accessing values that don't make sense (e.g. fee) when the tx is invalid an error.
  - Returning `MempoolAcceptResult` from ATMP makes the interface cleaner. The caller can get a const instead of passing in a mutable "out" param.
  - We don't have to be iterating through a bunch of lists for package validation, we can just return a `std::vector<MempoolAcceptResult>`.
  - We don't have to refactor all ATMP call sites again if/when we want to return more stuff from it.

ACKs for top commit:
  MarcoFalke:
    ACK 53e716e 💿
  jnewbery:
    Code review ACK 53e716e
  ariard:
    Code Review ACK 53e716e, I did tweak a bit the touched paths to see if we had good test coverage. Didn't find holes.

Tree-SHA512: fa6ec324a08ad9e6e55948615cda324cba176255708bf0a0a0f37cedb7a75311aa334ac6f223be7d8df3c7379502b1081102b9589f9a9afa1713ad3d9ab3c24f

Author: MarcoFalke

src/bench/block_assemble.cpp

@@ -48,9 +48,8 @@ static void AssembleBlock(benchmark::Bench& bench)
         LOCK(::cs_main); // Required for ::AcceptToMemoryPool.
 
         for (const auto& txr : txs) {
-            TxValidationState state;
-            bool ret{::AcceptToMemoryPool(*test_setup.m_node.mempool, state, txr, nullptr /* plTxnReplaced */, false /* bypass_limits */)};
-            assert(ret);
+            const MempoolAcceptResult res = ::AcceptToMemoryPool(*test_setup.m_node.mempool, txr, false /* bypass_limits */);
+            assert(res.m_result_type == MempoolAcceptResult::ResultType::VALID);
         }
     }
 

src/net_processing.cpp

@@ -2178,10 +2178,10 @@ void PeerManagerImpl::ProcessOrphanTx(std::set<uint256>& orphan_work_set)
         if (orphan_it == mapOrphanTransactions.end()) continue;
 
         const CTransactionRef porphanTx = orphan_it->second.tx;
-        TxValidationState state;
-        std::list<CTransactionRef> removed_txn;
+        const MempoolAcceptResult result = AcceptToMemoryPool(m_mempool, porphanTx, false /* bypass_limits */);
+        const TxValidationState& state = result.m_state;
 
-        if (AcceptToMemoryPool(m_mempool, state, porphanTx, &removed_txn, false /* bypass_limits */)) {
+        if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
             LogPrint(BCLog::MEMPOOL, "   accepted orphan tx %s\n", orphanHash.ToString());
             RelayTransaction(orphanHash, porphanTx->GetWitnessHash(), m_connman);
             for (unsigned int i = 0; i < porphanTx->vout.size(); i++) {
@@ -2193,7 +2193,7 @@ void PeerManagerImpl::ProcessOrphanTx(std::set<uint256>& orphan_work_set)
                 }
             }
             EraseOrphanTx(orphanHash);
-            for (const CTransactionRef& removedTx : removed_txn) {
+            for (const CTransactionRef& removedTx : result.m_replaced_transactions.value()) {
                 AddToCompactExtraTransactions(removedTx);
             }
             break;
@@ -3200,10 +3200,10 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
             return;
         }
 
-        TxValidationState state;
-        std::list<CTransactionRef> lRemovedTxn;
+        const MempoolAcceptResult result = AcceptToMemoryPool(m_mempool, ptx, false /* bypass_limits */);
+        const TxValidationState& state = result.m_state;
 
-        if (AcceptToMemoryPool(m_mempool, state, ptx, &lRemovedTxn, false /* bypass_limits */)) {
+        if (result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
             m_mempool.check(&::ChainstateActive().CoinsTip());
             // As this version of the transaction was acceptable, we can forget about any
             // requests for it.
@@ -3226,7 +3226,7 @@ void PeerManagerImpl::ProcessMessage(CNode& pfrom, const std::string& msg_type,
                 tx.GetHash().ToString(),
                 m_mempool.size(), m_mempool.DynamicMemoryUsage() / 1000);
 
-            for (const CTransactionRef& removedTx : lRemovedTxn) {
+            for (const CTransactionRef& removedTx : result.m_replaced_transactions.value()) {
                 AddToCompactExtraTransactions(removedTx);
             }
 

src/node/transaction.cpp

@@ -50,22 +50,22 @@ TransactionError BroadcastTransaction(NodeContext& node, const CTransactionRef t
     }
     if (!node.mempool->exists(hashTx)) {
         // Transaction is not already in the mempool.
-        TxValidationState state;
         if (max_tx_fee > 0) {
             // First, call ATMP with test_accept and check the fee. If ATMP
             // fails here, return error immediately.
-            CAmount fee{0};
-            if (!AcceptToMemoryPool(*node.mempool, state, tx,
-                nullptr /* plTxnReplaced */, false /* bypass_limits */, /* test_accept */ true, &fee)) {
-                return HandleATMPError(state, err_string);
-            } else if (fee > max_tx_fee) {
+            const MempoolAcceptResult result = AcceptToMemoryPool(*node.mempool, tx, false /* bypass_limits */,
+                                                                  true /* test_accept */);
+            if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {
+                return HandleATMPError(result.m_state, err_string);
+            } else if (result.m_base_fees.value() > max_tx_fee) {
                 return TransactionError::MAX_FEE_EXCEEDED;
             }
         }
         // Try to submit the transaction to the mempool.
-        if (!AcceptToMemoryPool(*node.mempool, state, tx,
-                nullptr /* plTxnReplaced */, false /* bypass_limits */)) {
-            return HandleATMPError(state, err_string);
+        const MempoolAcceptResult result = AcceptToMemoryPool(*node.mempool, tx, false /* bypass_limits */,
+                                                              false /* test_accept */);
+        if (result.m_result_type != MempoolAcceptResult::ResultType::VALID) {
+            return HandleATMPError(result.m_state, err_string);
         }
 
         // Transaction was accepted to the mempool.

src/rpc/rawtransaction.cpp

@@ -946,44 +946,35 @@ static RPCHelpMan testmempoolaccept()
     result_0.pushKV("txid", tx->GetHash().GetHex());
     result_0.pushKV("wtxid", tx->GetWitnessHash().GetHex());
 
-    TxValidationState state;
-    bool test_accept_res;
-    CAmount fee{0};
-    {
-        LOCK(cs_main);
-        test_accept_res = AcceptToMemoryPool(mempool, state, std::move(tx),
-            nullptr /* plTxnReplaced */, false /* bypass_limits */, /* test_accept */ true, &fee);
-    }
-
-    // Check that fee does not exceed maximum fee
-    if (test_accept_res && max_raw_tx_fee && fee > max_raw_tx_fee) {
-        result_0.pushKV("allowed", false);
-        result_0.pushKV("reject-reason", "max-fee-exceeded");
-        result.push_back(std::move(result_0));
-        return result;
-    }
-    result_0.pushKV("allowed", test_accept_res);
+    const MempoolAcceptResult accept_result = WITH_LOCK(cs_main, return AcceptToMemoryPool(mempool, std::move(tx),
+                                                  false /* bypass_limits */, /* test_accept */ true));
 
     // Only return the fee and vsize if the transaction would pass ATMP.
     // These can be used to calculate the feerate.
-    if (test_accept_res) {
-        result_0.pushKV("vsize", virtual_size);
-        UniValue fees(UniValue::VOBJ);
-        fees.pushKV("base", ValueFromAmount(fee));
-        result_0.pushKV("fees", fees);
+    if (accept_result.m_result_type == MempoolAcceptResult::ResultType::VALID) {
+        const CAmount fee = accept_result.m_base_fees.value();
+        // Check that fee does not exceed maximum fee
+        if (max_raw_tx_fee && fee > max_raw_tx_fee) {
+            result_0.pushKV("allowed", false);
+            result_0.pushKV("reject-reason", "max-fee-exceeded");
+        } else {
+            result_0.pushKV("allowed", true);
+            result_0.pushKV("vsize", virtual_size);
+            UniValue fees(UniValue::VOBJ);
+            fees.pushKV("base", ValueFromAmount(fee));
+            result_0.pushKV("fees", fees);
+        }
+        result.push_back(std::move(result_0));
     } else {
-        if (state.IsInvalid()) {
-            if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {
-                result_0.pushKV("reject-reason", "missing-inputs");
-            } else {
-                result_0.pushKV("reject-reason", strprintf("%s", state.GetRejectReason()));
-            }
+        result_0.pushKV("allowed", false);
+        const TxValidationState state = accept_result.m_state;
+        if (state.GetResult() == TxValidationResult::TX_MISSING_INPUTS) {
+            result_0.pushKV("reject-reason", "missing-inputs");
         } else {
             result_0.pushKV("reject-reason", state.GetRejectReason());
         }
+        result.push_back(std::move(result_0));
     }
-
-    result.push_back(std::move(result_0));
     return result;
 },
     };

src/test/txvalidation_tests.cpp

@@ -30,25 +30,21 @@ BOOST_FIXTURE_TEST_CASE(tx_mempool_reject_coinbase, TestChain100Setup)
 
     BOOST_CHECK(CTransaction(coinbaseTx).IsCoinBase());
 
-    TxValidationState state;
-
     LOCK(cs_main);
 
     unsigned int initialPoolSize = m_node.mempool->size();
+    const MempoolAcceptResult result = AcceptToMemoryPool(*m_node.mempool, MakeTransactionRef(coinbaseTx),
+                true /* bypass_limits */);
 
-    BOOST_CHECK_EQUAL(
-            false,
-            AcceptToMemoryPool(*m_node.mempool, state, MakeTransactionRef(coinbaseTx),
-                nullptr /* plTxnReplaced */,
-                true /* bypass_limits */));
+    BOOST_CHECK(result.m_result_type == MempoolAcceptResult::ResultType::INVALID);
 
     // Check that the transaction hasn't been added to mempool.
     BOOST_CHECK_EQUAL(m_node.mempool->size(), initialPoolSize);
 
     // Check that the validation state reflects the unsuccessful attempt.
-    BOOST_CHECK(state.IsInvalid());
-    BOOST_CHECK_EQUAL(state.GetRejectReason(), "coinbase");
-    BOOST_CHECK(state.GetResult() == TxValidationResult::TX_CONSENSUS);
+    BOOST_CHECK(result.m_state.IsInvalid());
+    BOOST_CHECK_EQUAL(result.m_state.GetRejectReason(), "coinbase");
+    BOOST_CHECK(result.m_state.GetResult() == TxValidationResult::TX_CONSENSUS);
 }
 
 BOOST_AUTO_TEST_SUITE_END()

src/test/txvalidationcache_tests.cpp

@@ -28,9 +28,9 @@ BOOST_FIXTURE_TEST_CASE(tx_mempool_block_doublespend, TestChain100Setup)
     const auto ToMemPool = [this](const CMutableTransaction& tx) {
         LOCK(cs_main);
 
-        TxValidationState state;
-        return AcceptToMemoryPool(*m_node.mempool, state, MakeTransactionRef(tx),
-            nullptr /* plTxnReplaced */, true /* bypass_limits */);
+        const MempoolAcceptResult result = AcceptToMemoryPool(*m_node.mempool, MakeTransactionRef(tx),
+            true /* bypass_limits */);
+        return result.m_result_type == MempoolAcceptResult::ResultType::VALID;
     };
 
     // Create a double-spend of mature coinbase txn:

src/test/validation_block_tests.cpp

@@ -283,15 +283,9 @@ BOOST_AUTO_TEST_CASE(mempool_locks_reorg)
         // Add the txs to the tx pool
         {
             LOCK(cs_main);
-            TxValidationState state;
-            std::list<CTransactionRef> plTxnReplaced;
             for (const auto& tx : txs) {
-                BOOST_REQUIRE(AcceptToMemoryPool(
-                    *m_node.mempool,
-                    state,
-                    tx,
-                    &plTxnReplaced,
-                    /* bypass_limits */ false));
+                const MempoolAcceptResult result = AcceptToMemoryPool(*m_node.mempool, tx, false /* bypass_limits */);
+                BOOST_REQUIRE(result.m_result_type == MempoolAcceptResult::ResultType::VALID);
             }
         }