[[refactor]] Check CTxMemPool options in constructor

This ensures that the tests run the same checks on the mempool options
that the init code also applies.

src/init.cpp

@@ -1523,16 +1523,14 @@ bool AppInitMain(NodeContext& node, interfaces::BlockAndHeaderTipInfo* tip_info)
     if (!result) {
         return InitError(util::ErrorString(result));
     }
-    mempool_opts.check_ratio = std::clamp<int>(mempool_opts.check_ratio, 0, 1'000'000);
-
-    int64_t descendant_limit_bytes = mempool_opts.limits.descendant_size_vbytes * 40;
-    if (mempool_opts.max_size_bytes < 0 || mempool_opts.max_size_bytes < descendant_limit_bytes) {
-        return InitError(strprintf(_("-maxmempool must be at least %d MB"), std::ceil(descendant_limit_bytes / 1'000'000.0)));
-    }
-    LogPrintf("* Using %.1f MiB for in-memory UTXO set (plus up to %.1f MiB of unused mempool space)\n", cache_sizes.coins * (1.0 / 1024 / 1024), mempool_opts.max_size_bytes * (1.0 / 1024 / 1024));
 
     for (bool fLoaded = false; !fLoaded && !ShutdownRequested(node);) {
-        node.mempool = std::make_unique<CTxMemPool>(mempool_opts);
+        bilingual_str mempool_error;
+        node.mempool = std::make_unique<CTxMemPool>(mempool_opts, mempool_error);
+        if (!mempool_error.empty()) {
+            return InitError(mempool_error);
+        }
+        LogPrintf("* Using %.1f MiB for in-memory UTXO set (plus up to %.1f MiB of unused mempool space)\n", cache_sizes.coins * (1.0 / 1024 / 1024), mempool_opts.max_size_bytes * (1.0 / 1024 / 1024));
 
         node.chainman = std::make_unique<ChainstateManager>(*Assert(node.shutdown), chainman_opts, blockman_opts);
         ChainstateManager& chainman = *node.chainman;

src/test/fuzz/mini_miner.cpp

@@ -33,7 +33,9 @@ void initialize_miner()
 FUZZ_TARGET(mini_miner, .init = initialize_miner)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
-    CTxMemPool pool{CTxMemPool::Options{}};
+    bilingual_str error;
+    CTxMemPool pool{CTxMemPool::Options{}, error};
+    Assert(error.empty());
     std::vector<COutPoint> outpoints;
     std::deque<COutPoint> available_coins = g_available_coins;
     LOCK2(::cs_main, pool.cs);
@@ -109,7 +111,9 @@ FUZZ_TARGET(mini_miner, .init = initialize_miner)
 FUZZ_TARGET(mini_miner_selection, .init = initialize_miner)
 {
     FuzzedDataProvider fuzzed_data_provider{buffer.data(), buffer.size()};
-    CTxMemPool pool{CTxMemPool::Options{}};
+    bilingual_str error;
+    CTxMemPool pool{CTxMemPool::Options{}, error};
+    Assert(error.empty());
     // Make a copy to preserve determinism.
     std::deque<COutPoint> available_coins = g_available_coins;
     std::vector<CTransactionRef> transactions;

src/test/fuzz/package_eval.cpp

@@ -126,8 +126,11 @@ CTxMemPool MakeMempool(FuzzedDataProvider& fuzzed_data_provider, const NodeConte
     mempool_opts.check_ratio = 1;
     mempool_opts.require_standard = fuzzed_data_provider.ConsumeBool();
 
+    // ... ignore the error since it might be beneficial to fuzz even when the
+    // mempool size is unreasonably small
+    bilingual_str error;
     // ...and construct a CTxMemPool from it
-    return CTxMemPool{mempool_opts};
+    return CTxMemPool{mempool_opts, error};
 }
 
 FUZZ_TARGET(tx_package_eval, .init = initialize_tx_pool)

src/test/fuzz/partially_downloaded_block.cpp

@@ -52,7 +52,9 @@ FUZZ_TARGET(partially_downloaded_block, .init = initialize_pdb)
 
     CBlockHeaderAndShortTxIDs cmpctblock{*block};
 
-    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+    bilingual_str error;
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node), error};
+    Assert(error.empty());
     PartiallyDownloadedBlock pdb{&pool};
 
     // Set of available transactions (mempool or extra_txn)

src/test/fuzz/rbf.cpp

@@ -56,7 +56,9 @@ FUZZ_TARGET(rbf, .init = initialize_rbf)
         return;
     }
 
-    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+    bilingual_str error;
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node), error};
+    Assert(error.empty());
 
     LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), NUM_ITERS)
     {
@@ -101,7 +103,9 @@ FUZZ_TARGET(package_rbf, .init = initialize_package_rbf)
     std::optional<CMutableTransaction> child = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider, TX_WITH_WITNESS);
     if (!child) return;
 
-    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+    bilingual_str error;
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node), error};
+    Assert(error.empty());
 
     // Add a bunch of parent-child pairs to the mempool, and remember them.
     std::vector<CTransaction> mempool_txs;

src/test/fuzz/tx_pool.cpp

@@ -126,7 +126,9 @@ CTxMemPool MakeMempool(FuzzedDataProvider& fuzzed_data_provider, const NodeConte
     mempool_opts.require_standard = fuzzed_data_provider.ConsumeBool();
 
     // ...and construct a CTxMemPool from it
-    return CTxMemPool{mempool_opts};
+    bilingual_str error;
+    return CTxMemPool{mempool_opts, error};
+    Assert(error.empty());
 }
 
 void CheckATMPInvariants(const MempoolAcceptResult& res, bool txid_in_mempool, bool wtxid_in_mempool)

src/test/fuzz/validation_load_mempool.cpp

@@ -40,7 +40,9 @@ FUZZ_TARGET(validation_load_mempool, .init = initialize_validation_load_mempool)
     SetMockTime(ConsumeTime(fuzzed_data_provider));
     FuzzedFileProvider fuzzed_file_provider{fuzzed_data_provider};
 
-    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+    bilingual_str error;
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node), error};
+    Assert(error.empty());
 
     auto& chainstate{static_cast<DummyChainState&>(g_setup->m_node.chainman->ActiveChainstate())};
     chainstate.SetMempool(&pool);

src/test/miner_tests.cpp

@@ -46,7 +46,9 @@ struct MinerTestingSetup : public TestingSetup {
         // pointer is not accessed, when the new one should be accessed
         // instead.
         m_node.mempool.reset();
-        m_node.mempool = std::make_unique<CTxMemPool>(MemPoolOptionsForTest(m_node));
+        bilingual_str error;
+        m_node.mempool = std::make_unique<CTxMemPool>(MemPoolOptionsForTest(m_node), error);
+        Assert(error.empty());
         return *m_node.mempool;
     }
     BlockAssembler AssemblerForTest(CTxMemPool& tx_mempool);

src/test/util/setup_common.cpp

@@ -229,7 +229,9 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, const std::vecto
     m_node.validation_signals = std::make_unique<ValidationSignals>(std::make_unique<SerialTaskRunner>(*m_node.scheduler));
 
     m_node.fee_estimator = std::make_unique<CBlockPolicyEstimator>(FeeestPath(*m_node.args), DEFAULT_ACCEPT_STALE_FEE_ESTIMATES);
-    m_node.mempool = std::make_unique<CTxMemPool>(MemPoolOptionsForTest(m_node));
+    bilingual_str error{};
+    m_node.mempool = std::make_unique<CTxMemPool>(MemPoolOptionsForTest(m_node), error);
+    Assert(error.empty());
 
     m_cache_sizes = CalculateCacheSizes(m_args);
 

src/txmempool.cpp

@@ -395,8 +395,8 @@ void CTxMemPoolEntry::UpdateAncestorState(int32_t modifySize, CAmount modifyFee,
     assert(int(nSigOpCostWithAncestors) >= 0);
 }
 
-CTxMemPool::CTxMemPool(const Options& opts)
-    : m_check_ratio{opts.check_ratio},
+CTxMemPool::CTxMemPool(const Options& opts, bilingual_str& error)
+    : m_check_ratio{std::clamp<int>(opts.check_ratio, 0, 1'000'000)},
       m_max_size_bytes{opts.max_size_bytes},
       m_expiry{opts.expiry},
       m_incremental_relay_feerate{opts.incremental_relay_feerate},
@@ -410,6 +410,10 @@ CTxMemPool::CTxMemPool(const Options& opts)
       m_limits{opts.limits},
       m_signals{opts.signals}
 {
+    int64_t descendant_limit_bytes = opts.limits.descendant_size_vbytes * 40;
+    if (opts.max_size_bytes < 0 || opts.max_size_bytes < descendant_limit_bytes) {
+        error = strprintf(_("-maxmempool must be at least %d MB"), std::ceil(descendant_limit_bytes / 1'000'000.0));
+    }
 }
 
 bool CTxMemPool::isSpent(const COutPoint& outpoint) const

src/txmempool.h

@@ -456,7 +456,7 @@ public:
      * accepting transactions becomes O(N^2) where N is the number of transactions
      * in the pool.
      */
-    explicit CTxMemPool(const Options& opts);
+    explicit CTxMemPool(const Options& opts, bilingual_str& error);
 
     /**
      * If sanity-checking is turned on, check makes sure the pool is