fix!: respect ep square only if legal (#375)

Disservin · web-flow · commit f3efcc6fb34d · 2025-06-08T23:55:40.000+02:00
This is a potentially breaking change for engines which don't handle this 100% correct since fastchess checks for 3 fold repetitions in the pv line and now it might realize that the game ended earlier and such as might mark moves as illegal which follow

Fixes the issue where the following position wasn't adjudicated due to 3 fold repetition. 
This previously wasn't the case because h5 was a pseudo legal ep square

```
[Variant "From Position"]
[FEN "6k1/1p2p1rp/rP1pR3/2pP1pP1/p1P2P1P/R5K1/8/8 b - - 0 1"]

1... h5 2. Rh6 Rh7 3. Re6 Rg7 4. Rh6 Rh7 5. Re6 Rg7
```
diff --git a/app/src/game/book/pgn_reader.cpp b/app/src/game/book/pgn_reader.cpp
@@ -52,7 +52,7 @@ class PGNVisitor : public chess::pgn::Visitor {
             return;
         }
 
-        board_.makeMove(move_i);
+        board_.makeMove<true>(move_i);
 
         if (board_.isGameOver().second != chess::GameResult::NONE) {
             early_stop_ = true;
diff --git a/app/src/game/epd/epd_builder.hpp b/app/src/game/epd/epd_builder.hpp
@@ -23,7 +23,7 @@ class EpdBuilder {
 
             if (illegal) break;
 
-            board.makeMove(chess::uci::uciToMove(board, move.move));
+            board.makeMove<true>(chess::uci::uciToMove(board, move.move));
         }
 
         epd << board.getEpd() << "\n";
diff --git a/app/src/game/pgn/pgn_builder.cpp b/app/src/game/pgn/pgn_builder.cpp
@@ -82,7 +82,7 @@ PgnBuilder::PgnBuilder(const config::Pgn &pgn_config, const MatchData &match, st
         const auto last     = std::next(it) == match_.moves.end();
         const auto move_str = addMove(board, *it, move_number, n_dots, illegal, last);
 
-        board.makeMove(chess::uci::uciToMove(board, it->move));
+        board.makeMove<true>(chess::uci::uciToMove(board, it->move));
 
         move_number++;
 
diff --git a/app/src/matchmaking/match/match.cpp b/app/src/matchmaking/match/match.cpp
@@ -82,7 +82,7 @@ Match::Match(const book::Opening& opening)
 
     const auto insert_move = [&](const auto& opening_move) {
         const auto move = uci::moveToUci(opening_move, board_.chess960());
-        board_.makeMove(opening_move);
+        board_.makeMove<true>(opening_move);
 
         return MoveData(move, "0.00", 0, 0, 0, 0, 0, true, true);
     };
@@ -360,7 +360,7 @@ bool Match::playMove(Player& us, Player& them) {
         return false;
     }
 
-    board_.makeMove(move);
+    board_.makeMove<true>(move);
 
     // CuteChess uses plycount/2 for its movenumber, which is wrong for epd books as it doesnt take
     // into account the fullmove counter of the starting FEN, leading to different behavior between
@@ -528,7 +528,7 @@ void Match::verifyPvLines(const Player& us) {
                 break;
             }
 
-            board.makeMove(uci::uciToMove(board, *it_start));
+            board.makeMove<true>(uci::uciToMove(board, *it_start));
 
             it_start++;
         }

Original file line number	Diff line number	Diff line change
`@@ -52,7 +52,7 @@ class PGNVisitor : public chess::pgn::Visitor {`
`52`	`52`	`return;`
`53`	`53`	`}`
`54`	`54`
`55`		`- board_.makeMove(move_i);`
	`55`	`+ board_.makeMove<true>(move_i);`
`56`	`56`
`57`	`57`	`if (board_.isGameOver().second != chess::GameResult::NONE) {`
`58`	`58`	`early_stop_ = true;`
Original file line number	Diff line number	Diff line change
`@@ -23,7 +23,7 @@ class EpdBuilder {`
`23`	`23`
`24`	`24`	`if (illegal) break;`
`25`	`25`
`26`		`- board.makeMove(chess::uci::uciToMove(board, move.move));`
	`26`	`+ board.makeMove<true>(chess::uci::uciToMove(board, move.move));`
`27`	`27`	`}`
`28`	`28`
`29`	`29`	`epd << board.getEpd() << "\n";`
Original file line number	Diff line number	Diff line change
`@@ -82,7 +82,7 @@ Match::Match(const book::Opening& opening)`
`82`	`82`
`83`	`83`	`const auto insert_move = [&](const auto& opening_move) {`
`84`	`84`	`const auto move = uci::moveToUci(opening_move, board_.chess960());`
`85`		`- board_.makeMove(opening_move);`
	`85`	`+ board_.makeMove<true>(opening_move);`
`86`	`86`
`87`	`87`	`return MoveData(move, "0.00", 0, 0, 0, 0, 0, true, true);`
`88`	`88`	`};`
`@@ -360,7 +360,7 @@ bool Match::playMove(Player& us, Player& them) {`
`360`	`360`	`return false;`
`361`	`361`	`}`
`362`	`362`
`363`		`- board_.makeMove(move);`
	`363`	`+ board_.makeMove<true>(move);`
`364`	`364`
`365`	`365`	`// CuteChess uses plycount/2 for its movenumber, which is wrong for epd books as it doesnt take`
`366`	`366`	`// into account the fullmove counter of the starting FEN, leading to different behavior between`
`@@ -528,7 +528,7 @@ void Match::verifyPvLines(const Player& us) {`
`528`	`528`	`break;`
`529`	`529`	`}`
`530`	`530`
`531`		`- board.makeMove(uci::uciToMove(board, *it_start));`
	`531`	`+ board.makeMove<true>(uci::uciToMove(board, *it_start));`
`532`	`532`
`533`	`533`	`it_start++;`
`534`	`534`	`}`