Merge #21062: refactor: return MempoolAcceptResult from ATMP

53e716ea11 [refactor] improve style for touched code (gzhao408)
174cb5330a [refactor] const ATMPArgs and non-const Workspace (gzhao408)
f82baf0762 [refactor] return MempoolAcceptResult (gzhao408)
9db10a5506 [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 53e716ea11 💿
  jnewbery:
    Code review ACK 53e716ea11
  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

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);
             }
         }