dgb(phase-b): tail-hashrate-score chain-walk endpoints SSOT + KAT - #411
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Lift the pure integer endpoint arithmetic of ShareTracker::score() (the per-tail approximate-hashrate ranking that drives best_tail selection) into a fenced header-only SSOT, coin/tail_score_endpoints.hpp: - end-point offset = CHAIN_LENGTH * 15 / 16 (get_nth_parent_hash dist) - trailing walk len = min(CHAIN_LENGTH / 16, end_point_acc_height) - short-chain guard = head_acc_height < CHAIN_LENGTH - unresolvable block = 1e6 confirmation fallback (tiny but non-zero score) - time span = max(1, block_span * BLOCK_PERIOD) - score = total_work / time_span vs the p2pool-dgb-scrypt data.py:843-855 oracle. The chain-walk halves (get_nth_parent_hash / get_chain / get_delta) stay in ShareTracker; this slice lifts only the arithmetic, with a non-circular KAT (8/8) deriving every expectation from the oracle formula + DGB net constants (CHAIN_LENGTH 2880/400, BLOCK_PERIOD 75), including two full-composite hand-derived score anchors. FENCED, additive: share_tracker.hpp NOT rewired (byte-identity delegation is the follow-on). Per-coin isolation: src/impl/dgb/ only. Test in both build.yml --target arms + dir CMakeLists.txt.
This was referenced Jun 24, 2026
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…ow-on) Production byte-identical delegation of the six pure-arithmetic sites in ShareTracker::score() onto the KAT-pinned coin/tail_score_endpoints.hpp SSOT (landed header-only in #411). The chain walk stays inside the member (it needs the verified skip-list / TrackerView); only the integer endpoint/guard/span arithmetic is delegated: - short-chain guard -> score_head_too_short - 15/16 endpoint offset -> score_endpoint_offset - /16 tail walk count -> score_tail_walk_count - unresolved-block span -> score_resolved_block_span - span clamp -> score_time_span - work/span divide -> score_value Value-identical (same int32_t span type, same uint288 divide); chain_length is a positive net constant so signed/unsigned (CL*15)/16 and CL/16 coincide. Diagnostic tail-ranking arithmetic, fenced to src/impl/dgb/, no consensus value semantics changed. Closes the #411 SSOT drift-risk (header was not yet referenced by the live score path). dgb_share_test 34/34; dgb_tail_score_endpoints_test 8/8.
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dgb: rewire ShareTracker::score onto coin/ tail_score SSOT (#411 follow-on)
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What
Phase-B SSOT slice: lift the pure integer endpoint arithmetic of
ShareTracker::score()— the per-tail approximate-hashrate ranking that drivesbest_tailselection (data.py:767-772) — into a fenced header-only SSOTsrc/impl/dgb/coin/tail_score_endpoints.hpp.Lifted (free functions over already-resolved inputs):
CHAIN_LENGTH*15/16(get_nth_parent_hash distance)min(CHAIN_LENGTH/16, end_point_acc_height)head_acc_height < CHAIN_LENGTHmax(1, block_span*BLOCK_PERIOD)and thework/time_spandivideThe chain-walk halves (get_nth_parent_hash / get_chain / get_delta) stay in ShareTracker (they need the skip-list / TrackerView).
Oracle
p2pool-dgb-scrypt
data.py:843-855ShareTracker.score(). Every KAT expectation hand-derived from the oracle formula + DGB net constants (CHAIN_LENGTH 2880 mainnet / 400 testnet, PARENT.BLOCK_PERIOD 75s) — non-circular, incl. two full-composite hand-derived score anchors (resolved 4-deep → 3000; unresolvable → 10).Fencing
share_tracker.hppNOT rewired (byte-identity delegation is the follow-on).src/impl/dgb/only.dgb_tail_score_endpoints_test8/8 green; registered in dir CMakeLists.txt + both build.yml--targetarms (ci: build test_dgb_subsidy in both Linux test jobs (fix master-red NOT_BUILT) #143 NOT_BUILT trap).No self-merge — integrator taps on full-rollup green.