Restore game state after restarting lichess-bot

Should lichess-bot need to be restarted for any reason, these changes will allow Xboard engines to resume a game that is still in progress. All prior moves will be sent so the engine can track 50-move and repetition information.
shashwat1705 · Mar 6, 2020 · d3306fa · d3306fa
1 parent 9362b39
commit d3306fa
Showing 1 changed file with 11 additions and 1 deletion.
diff --git a/engine_wrapper.py b/engine_wrapper.py
@@ -142,7 +142,13 @@ def __init__(self, board, commands, options=None, silence_stderr=False):
         if options:
             self._handle_options(options)
 
-        self.engine.setboard(board)
+        if board.fen() != chess.STARTING_FEN:
+            self.engine.force()
+            if board.root().fen() != chess.STARTING_FEN:
+                self.engine.setboard(board.root())
+            for move in board.move_stack:
+                self.engine.usermove(move)
+        self.last_fen_seen = board.fen()
 
         post_handler = chess.xboard.PostHandler()
         self.engine.post_handlers.append(post_handler)
@@ -176,11 +182,15 @@ def send_time(self):
         self.engine.level(0, self.minutes, self.seconds, self.inc)
 
     def send_last_move(self, board):
+        if board.fen() == self.last_fen_seen:
+            return
+
         self.engine.force()
         try:
             self.engine.usermove(board.peek())
         except IndexError:
             self.engine.setboard(board)
+        self.last_fen_seen = board.fen()
 
     def first_search(self, board, movetime):
         self.send_last_move(board)