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dgb(phase-b): delegate generate_share_transaction payout split to PPLNS SSOT helper #329

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Merged
frstrtr merged 1 commit into from
Jun 22, 2026
Merged

dgb(phase-b): delegate generate_share_transaction payout split to PPLNS SSOT helper #329

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93 changes: 20 additions & 73 deletions src/impl/dgb/share_check.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -9,6 +9,7 @@
#include "share_types.hpp"

#include <impl/dgb/coin/gentx_coinbase.hpp>
#include <impl/dgb/coin/pplns_payout_split.hpp>

#include <core/coin_params.hpp>
#include <core/hash.hpp>
Expand Down Expand Up @@ -1029,7 +1030,6 @@ uint256 generate_share_transaction(const ShareT& share, TrackerT& tracker, const
// donation = subsidy - sum(amounts)

auto gst_t1 = std::chrono::steady_clock::now(); // after PPLNS walk
std::map<std::vector<unsigned char>, uint64_t> amounts;

// Periodic dump of PPLNS weights for cross-impl comparison
{
Expand All @@ -1051,89 +1051,36 @@ uint256 generate_share_transaction(const ShareT& share, TrackerT& tracker, const
}
}

if (!total_weight.IsNull())
{
for (auto& [script, weight] : weights)
{
uint64_t amount;
if (use_v36_pplns)
{
// V36: amounts[script] = subsidy * weight / total_weight
uint288 num = uint288(subsidy) * weight;
amount = (num / total_weight).GetLow64();
}
else
{
// Pre-V36: amounts[script] = subsidy * (199 * weight) / (200 * total_weight)
uint288 num = uint288(subsidy) * (weight * 199);
uint288 den = total_weight * 200;
amount = (num / den).GetLow64();
}
if (amount > 0)
amounts[script] = amount;
}
}

// Pre-V36: add 0.5% finder fee to share creator
if (!use_v36_pplns)
{
auto finder_script = get_share_script(&share);
amounts[finder_script] += subsidy / 200;
}
// --- 2-3. PPLNS amount math + consensus output ordering (SSOT) ----------
// Steps 2-3 are now the single tracker-free helper compute_pplns_payout_split().
// The per-connection Stratum coinbase assembler draws the SAME split, so
// emission and this verification path cannot diverge on a payout satoshi.
// The helper is a verbatim lift of the former inline math (exact V36 /
// pre-V36 formulae, 0.5% finder fee, >=1-sat V36 donation floor with the
// (amount, script) tiebreak, and the ascending sort truncated to [-4000:]).
// Reference: frstrtr/p2pool-merged-v36 data.py generate_transaction().
auto finder_script = get_share_script(&share);
auto pplns_split = dgb::coin::compute_pplns_payout_split(
weights, total_weight, subsidy, use_v36_pplns, finder_script);
auto& payout_outputs = pplns_split.payout_outputs;
uint64_t donation_amount = pplns_split.donation_amount;

// Donation output = subsidy minus sum of all payout amounts
uint64_t sum_amounts = 0;
for (auto& [s, a] : amounts)
sum_amounts += a;
uint64_t donation_amount = (subsidy > sum_amounts) ? (subsidy - sum_amounts) : 0;
auto gst_t2 = std::chrono::steady_clock::now(); // after amounts+ordering

// Dump amounts for cross-impl debugging
// Dump payouts for cross-impl debugging
if (dump_diag) {
LOG_DEBUG_DIAG << "[GST-AMOUNTS] subsidy=" << subsidy << " addrs=" << amounts.size()
uint64_t sum_amounts = 0;
for (auto& [s, a] : payout_outputs) sum_amounts += a;
LOG_DEBUG_DIAG << "[GST-AMOUNTS] subsidy=" << subsidy << " addrs=" << payout_outputs.size()
<< " sum=" << sum_amounts << " donation=" << donation_amount
<< " prev=" << prev_hash.GetHex().substr(0,16);
for (auto& [s, a] : amounts) {
for (auto& [s, a] : payout_outputs) {
static const char* HX = "0123456789abcdef";
std::string sh; for (size_t i = 0; i < std::min(s.size(), size_t(10)); ++i) { sh += HX[s[i]>>4]; sh += HX[s[i]&0xf]; }
LOG_DEBUG_DIAG << "[GST-AMOUNTS] " << sh << "... = " << a;
}
}

// V36 consensus: donation output must carry >= 1 satoshi (a60f7f7f)
if (use_v36_pplns) {
if (donation_amount < 1 && subsidy > 0 && !amounts.empty()) {
// Deduct 1 sat from the largest miner payout
// Deterministic tiebreak: (amount, script) — largest script wins when equal
auto largest = std::max_element(amounts.begin(), amounts.end(),
[](const auto& a, const auto& b) {
if (a.second != b.second) return a.second < b.second;
return a.first < b.first;
});
if (largest != amounts.end() && largest->second > 0) {
largest->second -= 1;
sum_amounts -= 1;
donation_amount = subsidy - sum_amounts;
}
}
}

// --- 3. Build sorted output list ---
auto gst_t2 = std::chrono::steady_clock::now(); // after amounts
// Python: sorted(dests, key=lambda a: (amounts[a], a))[-4000:]
// = ascending by (amount, script), keep last 4000 (highest amounts)
std::vector<std::pair<std::vector<unsigned char>, uint64_t>> payout_outputs(
amounts.begin(), amounts.end());
std::sort(payout_outputs.begin(), payout_outputs.end(),
[](const auto& a, const auto& b) {
if (a.second != b.second) return a.second < b.second; // asc by amount
return a.first < b.first; // asc by script for tie-breaking
});

// Keep last MAX_OUTPUTS (highest amounts), matching Python's [-4000:]
constexpr size_t MAX_OUTPUTS = 4000;
if (payout_outputs.size() > MAX_OUTPUTS)
payout_outputs.erase(payout_outputs.begin(), payout_outputs.end() - MAX_OUTPUTS);

// --- 4. Serialise the coinbase transaction ---
// Wire layout (version|vin|vouts|locktime) and txid are produced by the
// SSOT assembler dgb::coin::assemble_gentx_coinbase() so that emission and
Expand Down
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