Merge bitcoin/bitcoin#25290: [kernel 3a/n] Decouple `CTxMemPool` from `ArgsManager`

d1684beabe5b738c2cc83de83e1aaef11a761b69 fees: Pass in a filepath instead of referencing gArgs (Carl Dong)
9a3d825c30e8e6118d74a4e568744cb9d03f7f5d init: Remove redundant -*mempool*, -limit* queries (Carl Dong)
6c5c60c4124293d948735756f84efc85262ea66f mempool: Use m_limit for UpdateTransactionsFromBlock (Carl Dong)
9e93b1030182eff92ef91181e17c7dd498c7e164 node/ifaces: Use existing MemPoolLimits (Carl Dong)
38af2bcf358a72b9457d370282e57f4be1c5c849 mempoolaccept: Use limits from mempool in constructor (Carl Dong)
9333427014695ac235c96d48791098168dfdc9db mempool: Introduce (still-unused) MemPoolLimits (Carl Dong)
716bb5fbd31077bbe99d11a54d6c2c250afc8085 scripted-diff: Rename anc/desc size limit vars to indicate SI unit (Carl Dong)
1ecc77321deb61b9f6888e4e10752b9d972fd26e scripted-diff: Rename DEFAULT_MEMPOOL_EXPIRY to indicate time unit (Carl Dong)
aa9141cd8185cb7ad532bc16feb9d302b05d9697 mempool: Pass in -mempoolexpiry instead of referencing gArgs (Carl Dong)
51c7a41a5eb6fcb60333812c770d80227cf7b64d init: Only determine maxmempool once (Carl Dong)
386c9472c8764738282e6d163b42e15a8feda7ea mempool: Make GetMinFee() with custom size protected (Carl Dong)
82f00de7a6a60cbc9ad0c6e1d0ffb1bc70c49af5 mempool: Pass in -maxmempool instead of referencing gArgs (Carl Dong)
f1941e8bfd2eecc478c7660434b1ebf6a64095a0 pool: Add and use MemPoolOptions, ApplyArgsManOptions (Carl Dong)
0199bd35bb44e32ee0db9b51c9d1bd7518c26f19 fuzz/rbf: Add missing TestingSetup (Carl Dong)
ccbaf546a68d6cda8ed3efd0598c0e4121b366bb scripted-diff: Rename DEFAULT_MAX_MEMPOOL_SIZE to indicate SI unit (Carl Dong)
fc02f77ca604f0221171bfde3059b34f5d0fb1cd ArgsMan: Add Get*Arg functions returning optional (Carl Dong)

Pull request description:

  This is part of the `libbitcoinkernel` project: #24303, https://github.com/bitcoin/bitcoin/projects/18

  -----

  As mentioned in the Stage 1 Step 2 description of [the `libbitcoinkernel` project](https://github.com/bitcoin/bitcoin/issues/24303), `ArgsManager` will not be part of `libbitcoinkernel`. Therefore, it is important that we remove any dependence on `ArgsManager` by code that will be part of `libbitcoinkernel`. This is the first in a series of PRs aiming to achieve this.

  This PR removes `CTxMemPool+MempoolAccept`'s dependency on `ArgsManager` by introducing a `CTxMemPool::Options` struct, which is used to specify `CTxMemPool`'s various options at construction time.

  These options are:
  - `-maxmempool` -> `CTxMemPool::Options::max_size`
  - `-mempoolexpiry` -> `CTxMemPool::Options::expiry`
  - `-limitancestorcount` -> `CTxMemPool::Options::limits::ancestor_count`
  - `-limitancestorsize` -> `CTxMemPool::Options::limits::ancestor_size`
  - `-limitdescendantcount` -> `CTxMemPool::Options::limits::descendant_count`
  - `-limitdescendantsize` -> `CTxMemPool::Options::limits::descendant_size`

  More context can be gleaned from the commit messages. The important commits are:

  - 56eb479ded8bfb2ef635bb6f3b484f9d5952c70d "pool: Add and use MemPoolOptions, ApplyArgsManOptions"
  - a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
  - 6f4bf3ede5812b374828f08fc728ceded2f10024 "mempool: Pass in -mempoolexpiry instead of referencing gArgs"
  - 5958a7fe4806599fc620ee8c1a881ca10fa2dd16 "mempool: Introduce (still-unused) MemPoolLimits"

  Reviewers: Help needed in the following commits (see commit messages):
  - a1e08b70f3068f4e8def1c630d8f50cd54da7832 "mempool: Pass in -maxmempool instead of referencing gArgs"
  - 0695081a797e9a5d7787b78b0f8289dafcc6bff7 "node/ifaces: Use existing MemPoolLimits"

  Note to Reviewers: There are perhaps an infinite number of ways to architect `CTxMemPool::Options`, the current one tries to keep it simple, usable, and flexible. I hope we don't spend too much time arguing over the design here since that's not the point. In the case that you're 100% certain that a different design is strictly better than this one in every regard, please show us a fully-implemented branch.

  -----

  TODO:
  - [x] Use the more ergonomic `CTxMemPool::Options` where appropriate
  - [x] Doxygen comments for `ApplyArgsManOptions`, `MemPoolOptions`

  -----

  Questions for Reviewers:
  1. Should we use `std::chrono::seconds` for `CTxMemPool::Options::expiry` and `CTxMemPool::m_expiry` instead of an `int64_t`? Something else? (`std::chrono::hours`?)
  2. Should I merge `CTxMemPool::Limits` inside `CTxMemPool::Options`?

ACKs for top commit:
  MarcoFalke:
    ACK d1684beabe5b738c2cc83de83e1aaef11a761b69 🍜
  ryanofsky:
    Code review ACK d1684beabe5b738c2cc83de83e1aaef11a761b69. Just minor cleanups since last review, mostly switching to brace initialization

Tree-SHA512: 2c138e52d69f61c263f1c3648f01c801338a8f576762c815f478ef5148b8b2f51e91ded5c1be915e678c0b14f6cfba894b82afec58d999d39a7bb7c914736e0b

5 files changed, 53 insertions, 8 deletions

diff --git a/src/test/fuzz/policy_estimator.cpp b/src/test/fuzz/policy_estimator.cpp
index e4d95f72a0..58c19a91cb 100644
--- a/src/test/fuzz/policy_estimator.cpp
+++ b/src/test/fuzz/policy_estimator.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <policy/fees.h>
+#include <policy/fees_args.h>
 #include <primitives/transaction.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
@@ -15,15 +16,20 @@
 #include <string>
 #include <vector>
 
+namespace {
+const BasicTestingSetup* g_setup;
+} // namespace
+
 void initialize_policy_estimator()
 {
     static const auto testing_setup = MakeNoLogFileContext<>();
+    g_setup = testing_setup.get();
 }
 
 FUZZ_TARGET_INIT(policy_estimator, initialize_policy_estimator)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
-    CBlockPolicyEstimator block_policy_estimator;
+    CBlockPolicyEstimator block_policy_estimator{FeeestPath(*g_setup->m_node.args)};
     LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {
         CallOneOf(
             fuzzed_data_provider,
diff --git a/src/test/fuzz/policy_estimator_io.cpp b/src/test/fuzz/policy_estimator_io.cpp
index 9021d95954..77402c260a 100644
--- a/src/test/fuzz/policy_estimator_io.cpp
+++ b/src/test/fuzz/policy_estimator_io.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <policy/fees.h>
+#include <policy/fees_args.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
@@ -11,9 +12,14 @@
 #include <cstdint>
 #include <vector>
 
+namespace {
+const BasicTestingSetup* g_setup;
+} // namespace
+
 void initialize_policy_estimator_io()
 {
     static const auto testing_setup = MakeNoLogFileContext<>();
+    g_setup = testing_setup.get();
 }
 
 FUZZ_TARGET_INIT(policy_estimator_io, initialize_policy_estimator_io)
@@ -22,7 +28,7 @@ FUZZ_TARGET_INIT(policy_estimator_io, initialize_policy_estimator_io)
     FuzzedAutoFileProvider fuzzed_auto_file_provider = ConsumeAutoFile(fuzzed_data_provider);
     CAutoFile fuzzed_auto_file = fuzzed_auto_file_provider.open();
     // Re-using block_policy_estimator across runs to avoid costly creation of CBlockPolicyEstimator object.
-    static CBlockPolicyEstimator block_policy_estimator;
+    static CBlockPolicyEstimator block_policy_estimator{FeeestPath(*g_setup->m_node.args)};
     if (block_policy_estimator.Read(fuzzed_auto_file)) {
         block_policy_estimator.Write(fuzzed_auto_file);
     }
diff --git a/src/test/fuzz/rbf.cpp b/src/test/fuzz/rbf.cpp
index 8dcaa609b5..4801635791 100644
--- a/src/test/fuzz/rbf.cpp
+++ b/src/test/fuzz/rbf.cpp
@@ -2,12 +2,14 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
+#include <mempool_args.h>
 #include <policy/rbf.h>
 #include <primitives/transaction.h>
 #include <sync.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
+#include <test/util/setup_common.h>
 #include <txmempool.h>
 
 #include <cstdint>
@@ -15,7 +17,17 @@
 #include <string>
 #include <vector>
 
-FUZZ_TARGET(rbf)
+namespace {
+const BasicTestingSetup* g_setup;
+} // namespace
+
+void initialize_rbf()
+{
+    static const auto testing_setup = MakeNoLogFileContext<>();
+    g_setup = testing_setup.get();
+}
+
+FUZZ_TARGET_INIT(rbf, initialize_rbf)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
     SetMockTime(ConsumeTime(fuzzed_data_provider));
@@ -23,8 +35,11 @@ FUZZ_TARGET(rbf)
     if (!mtx) {
         return;
     }
-    CTxMemPool pool;
-    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000) {
+
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+
+    LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 10000)
+    {
         const std::optional<CMutableTransaction> another_mtx = ConsumeDeserializable<CMutableTransaction>(fuzzed_data_provider);
         if (!another_mtx) {
             break;
diff --git a/src/test/fuzz/tx_pool.cpp b/src/test/fuzz/tx_pool.cpp
index 4f40608c4f..2d88ee295b 100644
--- a/src/test/fuzz/tx_pool.cpp
+++ b/src/test/fuzz/tx_pool.cpp
@@ -3,6 +3,8 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <consensus/validation.h>
+#include <mempool_args.h>
+#include <node/context.h>
 #include <node/miner.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
@@ -15,6 +17,7 @@
 #include <validationinterface.h>
 
 using node::BlockAssembler;
+using node::NodeContext;
 
 namespace {
 
@@ -121,6 +124,19 @@ void MockTime(FuzzedDataProvider& fuzzed_data_provider, const CChainState& chain
     SetMockTime(time);
 }
 
+CTxMemPool MakeMempool(const NodeContext& node)
+{
+    // Take the default options for tests...
+    CTxMemPool::Options mempool_opts{MemPoolOptionsForTest(node)};
+
+    // ...override specific options for this specific fuzz suite
+    mempool_opts.estimator = nullptr;
+    mempool_opts.check_ratio = 1;
+
+    // ...and construct a CTxMemPool from it
+    return CTxMemPool{mempool_opts};
+}
+
 FUZZ_TARGET_INIT(tx_pool_standard, initialize_tx_pool)
 {
     FuzzedDataProvider fuzzed_data_provider(buffer.data(), buffer.size());
@@ -142,7 +158,7 @@ FUZZ_TARGET_INIT(tx_pool_standard, initialize_tx_pool)
     // The sum of the values of all spendable outpoints
     constexpr CAmount SUPPLY_TOTAL{COINBASE_MATURITY * 50 * COIN};
 
-    CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
+    CTxMemPool tx_pool_{MakeMempool(node)};
     MockedTxPool& tx_pool = *static_cast<MockedTxPool*>(&tx_pool_);
 
     chainstate.SetMempool(&tx_pool);
@@ -320,7 +336,7 @@ FUZZ_TARGET_INIT(tx_pool, initialize_tx_pool)
         txids.push_back(ConsumeUInt256(fuzzed_data_provider));
     }
 
-    CTxMemPool tx_pool_{/*estimator=*/nullptr, /*check_ratio=*/1};
+    CTxMemPool tx_pool_{MakeMempool(node)};
     MockedTxPool& tx_pool = *static_cast<MockedTxPool*>(&tx_pool_);
 
     LIMITED_WHILE(fuzzed_data_provider.ConsumeBool(), 300)
diff --git a/src/test/fuzz/validation_load_mempool.cpp b/src/test/fuzz/validation_load_mempool.cpp
index c2aaf486c5..9532610f8d 100644
--- a/src/test/fuzz/validation_load_mempool.cpp
+++ b/src/test/fuzz/validation_load_mempool.cpp
@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <chainparamsbase.h>
+#include <mempool_args.h>
 #include <test/fuzz/FuzzedDataProvider.h>
 #include <test/fuzz/fuzz.h>
 #include <test/fuzz/util.h>
@@ -30,7 +31,8 @@ FUZZ_TARGET_INIT(validation_load_mempool, initialize_validation_load_mempool)
     SetMockTime(ConsumeTime(fuzzed_data_provider));
     FuzzedFileProvider fuzzed_file_provider = ConsumeFile(fuzzed_data_provider);
 
-    CTxMemPool pool{};
+    CTxMemPool pool{MemPoolOptionsForTest(g_setup->m_node)};
+
     auto fuzzed_fopen = [&](const fs::path&, const char*) {
         return fuzzed_file_provider.open();
     };