# HG changeset patch
# User Laman
# Date 2017-12-16 15:56:41
# Node ID 231b6d9b956192d68aa32f05f770c2e9aab5ebf2
# Parent  32221aadca28d27c73ac5325216a8f777cedf47a

engine: slightly enhanced handling movelist

diff --git a/src/go/engine.py b/src/go/engine.py
--- a/src/go/engine.py
+++ b/src/go/engine.py
@@ -66,7 +66,8 @@ class Engine:
 
 	def dfs(self,state2,limit):
 		g=self._g
-		for (r,c) in self._moveList[(1-g.toMove)>>1]:
+		moveSet=self._moveList[(1-g.toMove)>>1]
+		for (r,c) in moveSet.copy():
 			if g.board[r][c]!=EMPTY: continue
 			neighbours=(
 				g.board[r-1][c] if r>0 else None,
@@ -75,18 +76,27 @@ class Engine:
 				g.board[r][c+1] if c+1<g.boardSize else None
 			)
 			if not g.doMove(g.toMove,r,c): continue
+			moveSet.remove((r,c))
 			captured=tuple(
 				coords for (i,coords) in enumerate(((r-1,c),(r+1,c),(r,c-1),(r,c+1)))
 				if neighbours[i] is not None and neighbours[i]!=EMPTY and g.board[coords[0]][coords[1]]==EMPTY
 			)
-			if g.hash()==state2.hash(): return [(-1*g.toMove,r,c)]
+
+			if g.hash()==state2.hash():
+				g.undoMove(r,c,captured)
+				moveSet.add((r,c))
+				return [(g.toMove,r,c)]
+
 			if limit>1:
-				toMove=-1*g.toMove
 				seq=self.dfs(state2,limit-1)
 				if seq:
-					seq.append((toMove,r,c))
+					g.undoMove(r,c,captured)
+					moveSet.add((r,c))
+					seq.append((g.toMove,r,c))
 					return seq
+
 			g.undoMove(r,c,captured)
+			moveSet.add((r,c))
 		return False
 
 eng=Engine()