dash: add sharechain pool-peer state (S8 pool-node leaf 1)

DASH lacked the p2pool sharechain pool-node layer that btc and dgb both
carry (node.hpp/peer.hpp/messages.hpp/share_tracker.hpp/share_messages.hpp),
which blocks the full gate (b) bind/dial-crosses-shares path. This is leaf 1:
the per-peer state struct.

src/impl/dash/peer.hpp — dash::Peer, analog of btc::Peer/dgb::Peer: negotiated
version/subversion/services/nonce from the version handshake, connection
timestamp, and the remembered-tx protocol sets (m_remote_txs hash set +
m_remembered_txs hash->coin::Transaction map). Pure header-only state, no IO.

test/test_dash_peer.cpp — 5 KATs: fresh-peer defaults, version-handshake
round-trip, remote-tx set dedup, remembered-tx map roundtrip+erase, monotonic
connection timestamps. 5/5 green, non-hollow.

Strictly fenced to src/impl/dash/ + test wiring (CMakeLists + build.yml
allowlist); no bitcoin_family/src/core/other-coin touch.

Author: frstrtr

.github/workflows/build.yml

@@ -82,7 +82,7 @@ jobs:
                     test_threading test_weights \
                     test_header_chain test_mempool test_template_builder \
                     test_doge_chain test_compact_blocks test_dash_x11_kat \
-                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_cb_payee \
+                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_cb_payee test_dash_peer \
                     test_multiaddress_pplns test_pplns_stress \
                     test_hash_link test_decay_pplns \
                     test_pplns_consensus \
@@ -226,7 +226,7 @@ jobs:
                     test_threading test_weights \
                     test_header_chain test_mempool test_template_builder \
                     test_doge_chain test_compact_blocks test_dash_x11_kat \
-                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_cb_payee \
+                    test_dash_header_chain test_dash_block_replay test_dash_conformance test_dash_subsidy test_dash_mempool test_dash_simplifiedmns test_dash_quorum test_dash_quorum_root test_dash_mn_state test_dash_embedded_gbt test_dash_smldiff test_dash_p2p_messages test_dash_p2p_connection test_dash_p2p_node test_dash_node_interface test_dash_config test_dash_broadcaster test_dash_broadcaster_full test_dash_share_hash_link test_dash_block_relay test_dash_rpc_request test_dash_rpc_conf test_dash_block_producer test_dash_embedded_relay_e2e test_dash_block_relay_plan test_dash_version_activation_latch test_dash_block_relay_binding test_dash_block_relay_dual_arm test_dash_coinbase_parity test_dash_donation_combined test_dash_g3_assembled test_dash_work_target test_dash_work_job_targets test_dash_cb_payee test_dash_peer \
                     test_hash_link test_decay_pplns \
                     test_pplns_consensus \
                     test_v36_script_sorting test_v36_cross_impl_refhash \

src/impl/dash/peer.hpp

@@ -0,0 +1,43 @@
+#pragma once
+
+// Dash p2pool sharechain pool-peer state.
+//
+// S8 pool-node leaf 1 of N. Mirrors btc::Peer / dgb::Peer: the per-peer state a
+// pool Node keeps for every connected p2pool share-network peer (NOT a dashd
+// coin-daemon peer — that layer is coin/p2p_connection.hpp). Tracks the
+// negotiated version/subversion/services from the `version` handshake, the
+// connection timestamp, and the remembered-transaction sets used by the
+// share-message protocol (remote_txs = hashes the peer advertises; remembered_txs
+// = full txs we have forwarded/learned, keyed by hash).
+//
+// Pure state struct, no socket/IO — header-only, rig-free, fenced to src/impl/dash/.
+
+#include "coin/transaction.hpp"
+
+#include <chrono>
+#include <map>
+#include <optional>
+#include <set>
+#include <string>
+
+#include <core/uint256.hpp>
+
+namespace dash
+{
+
+struct Peer
+{
+    // === negotiated via the `version` handshake ===
+    std::optional<uint32_t> m_other_version;
+    std::string m_other_subversion;
+    uint64_t m_other_services{0};
+    uint64_t m_nonce{0};
+
+    std::chrono::steady_clock::time_point m_connected_at{std::chrono::steady_clock::now()};
+
+    // === remembered-transaction protocol state ===
+    std::set<uint256> m_remote_txs;                       // hashes the remote peer has advertised
+    std::map<uint256, coin::Transaction> m_remembered_txs; // full txs keyed by hash
+};
+
+}; // namespace dash

test/CMakeLists.txt

@@ -491,6 +491,16 @@ if (BUILD_TESTING AND GTest_FOUND)
     target_link_libraries(test_dash_config PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39)
     gtest_add_tests(test_dash_config "" AUTO)
 
+    add_executable(test_dash_peer test_dash_peer.cpp)
+    target_link_libraries(test_dash_peer PRIVATE
+        GTest::gtest_main GTest::gtest
+        dash_x11 core
+        nlohmann_json::nlohmann_json
+        ${Boost_LIBRARIES}
+    )
+    target_link_libraries(test_dash_peer PRIVATE c2pool_payout c2pool_hashrate c2pool_merged_mining)  # OBJECT-lib SCC direct-naming (#22/#39)
+    gtest_add_tests(test_dash_peer "" AUTO)
+
     # additive: pure persisted activation-latch (header-only version_activation_latch.hpp);
     # mirrors the test_dash_config link set (nlohmann_json + core), no ltc/pool SCC dependency.
     add_executable(test_dash_version_activation_latch test_dash_version_activation_latch.cpp)

test/test_dash_peer.cpp

@@ -0,0 +1,102 @@
+/// Phase S8 — Dash sharechain pool-node leaf 1: per-peer state (src/impl/dash/peer.hpp).
+///
+/// dash::Peer is the analog of btc::Peer / dgb::Peer: the state a pool Node holds
+/// for each connected p2pool share-network peer. The pool-node bridge (node.hpp,
+/// a later leaf) keys a Peer off every connection and drives it from the share
+/// message handlers. This KAT pins the observable contract those handlers read:
+///
+///   (a) fresh-peer defaults — no negotiated version yet, empty subversion,
+///       zeroed services/nonce, empty remember-sets, connection time stamped.
+///   (b) version-handshake fields round-trip (what the `version` handler writes).
+///   (c) the remembered-tx protocol state: m_remote_txs is a dedup hash set and
+///       m_remembered_txs maps hash -> full coin::Transaction with erase.
+///   (d) connection timestamps are monotonic across successive peers.
+
+#include <impl/dash/peer.hpp>
+#include <impl/dash/coin/transaction.hpp>
+
+#include <core/uint256.hpp>
+
+#include <gtest/gtest.h>
+
+#include <chrono>
+
+using dash::Peer;
+
+namespace
+{
+uint256 H(uint8_t b)
+{
+    uint256 h;
+    h.begin()[0] = b;
+    return h;
+}
+} // namespace
+
+TEST(DashPeer, FreshDefaultsAreSane)
+{
+    Peer p;
+    EXPECT_FALSE(p.m_other_version.has_value());
+    EXPECT_TRUE(p.m_other_subversion.empty());
+    EXPECT_EQ(p.m_other_services, 0u);
+    EXPECT_EQ(p.m_nonce, 0u);
+    EXPECT_TRUE(p.m_remote_txs.empty());
+    EXPECT_TRUE(p.m_remembered_txs.empty());
+    EXPECT_LE(p.m_connected_at, std::chrono::steady_clock::now());
+}
+
+TEST(DashPeer, VersionHandshakeRoundTrip)
+{
+    Peer p;
+    p.m_other_version = 70238u;        // dashd-aligned proto seen on the wire
+    p.m_other_subversion = "/c2pool-dash:0.1/";
+    p.m_other_services = 0x9u;
+    p.m_nonce = 0xdeadbeefull;
+
+    ASSERT_TRUE(p.m_other_version.has_value());
+    EXPECT_EQ(*p.m_other_version, 70238u);
+    EXPECT_EQ(p.m_other_subversion, "/c2pool-dash:0.1/");
+    EXPECT_EQ(p.m_other_services, 0x9u);
+    EXPECT_EQ(p.m_nonce, 0xdeadbeefull);
+}
+
+TEST(DashPeer, RemoteTxSetDedups)
+{
+    Peer p;
+    p.m_remote_txs.insert(H(1));
+    p.m_remote_txs.insert(H(2));
+    p.m_remote_txs.insert(H(1)); // duplicate advertise
+    EXPECT_EQ(p.m_remote_txs.size(), 2u);
+    EXPECT_EQ(p.m_remote_txs.count(H(1)), 1u);
+    EXPECT_EQ(p.m_remote_txs.count(H(9)), 0u);
+}
+
+TEST(DashPeer, RememberedTxRoundTripAndErase)
+{
+    Peer p;
+
+    dash::coin::MutableTransaction mtx;
+    mtx.version = 2;
+    mtx.type = 5;          // DIP4 CBTX
+    mtx.locktime = 99;
+    dash::coin::Transaction tx(mtx);
+
+    const uint256 key = H(7);
+    p.m_remembered_txs.emplace(key, tx);
+
+    auto it = p.m_remembered_txs.find(key);
+    ASSERT_NE(it, p.m_remembered_txs.end());
+    EXPECT_EQ(it->second.version, 2);
+    EXPECT_EQ(it->second.type, 5);
+    EXPECT_EQ(it->second.locktime, 99u);
+
+    EXPECT_EQ(p.m_remembered_txs.erase(key), 1u);
+    EXPECT_TRUE(p.m_remembered_txs.empty());
+}
+
+TEST(DashPeer, ConnectedAtMonotonicAcrossPeers)
+{
+    Peer a;
+    Peer b;
+    EXPECT_LE(a.m_connected_at, b.m_connected_at);
+}