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Fix bug affecting reversible status of pawn moves for threefold repetition detection #421

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Merged
TheRealGioviok merged 2 commits into from
Aug 5, 2026
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Merged

Fix bug affecting reversible status of pawn moves for threefold repetition detection #421

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3693ea2
Bench: 12674412
TheRealGioviok Aug 4, 2026
c18839e
Bench: 13841007
TheRealGioviok Aug 4, 2026
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2 changes: 1 addition & 1 deletion src/position.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -499,8 +499,8 @@
m8x64 pinner = maybe_pinner1 & maybe_pinner2;

// Does this ray have a pinner?
const m8x64 has_pinner = geometry::ray_fill(pinner);

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src/position.cpp:502:17 [readability-identifier-naming] 

invalid case style for constant 'has_pinner'
const m8x64 pinned = maybe_pinned & has_pinner;

Check warning on line 503 in src/position.cpp

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src/position.cpp:503:17 [readability-identifier-naming] 

invalid case style for constant 'pinned'

u8x64 nonmasked_pinned_ids =
geometry::lane_broadcast(pinned.mask(ray_places & u8x64::splat(0xF)));
Expand Down Expand Up @@ -991,7 +991,7 @@
return os;
}

bool Position::is_reversible(Move move) {
bool Position::is_reversible(Move move) const {
return !(move.is_capture() || move.is_promotion() || move.is_castle()
|| (m_board[move.from()].ptype() == PieceType::Pawn));
}
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2 changes: 1 addition & 1 deletion src/position.hpp
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Expand Up @@ -305,7 +305,7 @@ struct Position {

[[nodiscard]] u16 get_50mr_counter() const;

[[nodiscard]] bool is_reversible(Move move);
[[nodiscard]] bool is_reversible(Move move) const;

const std::array<Wordboard, 2> calc_attacks_slow();
const std::array<PieceMask, 2> calc_attacks_slow(Square sq);
Expand Down
6 changes: 3 additions & 3 deletions src/search.cpp
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Expand Up @@ -579,7 +579,7 @@ Value Worker::search(

ss->cont_hist_entry = &m_td.history.get_cont_hist_entry(pos, m);
Position pos_after = pos.move(m, m_td.push_psqt_state(), &m_searcher.tt);
repetition_info.push(pos_after.get_hash_key(), pos_after.is_reversible(m));
repetition_info.push(pos_after.get_hash_key(), pos.is_reversible(m));

Value probcut_value = -quiesce<IS_MAIN, false>(pos_after, ss + 1, -probcut_beta,
-probcut_beta + 1, ply + 1);
Expand Down Expand Up @@ -740,7 +740,7 @@ Value Worker::search(
moves_played++;

// Put hash into repetition table. TODO: encapsulate this and any other future adjustment to do "on move" into a proper function
repetition_info.push(pos_after.get_hash_key(), pos_after.is_reversible(m));
repetition_info.push(pos_after.get_hash_key(), pos.is_reversible(m));

// Get search value
Depth new_depth = depth - 1 + extension;
Expand Down Expand Up @@ -1066,7 +1066,7 @@ Value Worker::quiesce(const Position& pos, Stack* ss, Value alpha, Value beta, i
moves.skip_quiets();

// Put hash into repetition table. TODO: encapsulate this and any other future adjustment to do "on move" into a proper function
repetition_info.push(pos_after.get_hash_key(), pos_after.is_reversible(m));
repetition_info.push(pos_after.get_hash_key(), pos.is_reversible(m));

// Get search value
Value value = -quiesce<IS_MAIN, PV_NODE>(pos_after, ss + 1, -beta, -alpha, ply + 1);
Expand Down
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