refactor: return recoverable errors from make_move

2 files changed, 21 insertions, 8 deletions

diff --git a/src/board/engine.rs b/src/board/engine.rs
index 2c6e47a..4fe8652 100644
--- a/src/board/engine.rs
+++ b/src/board/engine.rs
@@ -32,7 +32,7 @@ impl Board {
             let ep_target_before = self.ep_target.clone();
             let castling_rights_before = self.castling_rights.clone();
             let hash_before = self.hash.clone();
-            let captured_piece = self.make_move(mov);
+            let captured_piece = self.make_move(mov).unwrap();
             // King can not be in check after our own move
             if !self.is_king_in_check(color) {
                 if depth == 1 {
@@ -135,7 +135,10 @@ impl Board {
             let ep_target_before = self.ep_target.clone();
             let castling_rights_before = self.castling_rights.clone();
             let hash_before = self.hash.clone();
-            let captured_piece = self.make_move(mov);
+            let captured_piece = match self.make_move(mov) {
+                Ok(piece) => piece,
+                Err(err) => panic!("Handle me [{:?}]", err),
+            };
 
             if !self.is_king_in_check(color) {
                 let (mut score, mut subtree_pv) = self.negamax_search(-beta, -alpha, depth_left - 1);
@@ -184,7 +187,7 @@ impl Board {
             let ep_target_before = self.ep_target.clone();
             let castling_rights_before = self.castling_rights.clone();
             let hash_before = self.hash.clone();
-            let captured_piece = self.make_move(*mov);
+            let captured_piece = self.make_move(*mov).unwrap();
 
             if !self.is_king_in_check(color) {
                 let evaluation = -self.quiscence(-beta, -alpha);
diff --git a/src/board/mod.rs b/src/board/mod.rs
index 19c25ac..2b580b5 100644
--- a/src/board/mod.rs
+++ b/src/board/mod.rs
@@ -77,6 +77,11 @@ const PIECE_CHARS: [&str; 12] = [
     "♙", "♘", "♗", "♖", "♕", "♔",
 ];
 
+#[derive(Debug)]
+pub enum MakeMoveError {
+    PieceNotFound(String),
+}
+
 
 #[allow(unused)]
 impl Board {
@@ -485,10 +490,9 @@ impl Board {
         mobility
     }
 
-
     /// *Blindlessly* apply a move without any validation
     /// Move should be validated beforehand
-    pub fn make_move(&mut self, mov: Move) -> Option<PieceType> {
+    pub fn make_move(&mut self, mov: Move) -> Result<Option<PieceType>,MakeMoveError> {
         let move_source_bb = mov.source.to_bitboard();
         let move_target_bb = mov.target.to_bitboard();
 
@@ -521,7 +525,11 @@ impl Board {
                         self.hash ^= self.zobrist_seed[pawn_type * 12 + captured_square as usize];
                         Some(PieceType::from(pawn_type))
                     }
-                    None => panic!("Pawn captured by En Passant was not found"),
+                    None => {
+                        return Err(MakeMoveError::PieceNotFound(
+                                String::from("Pawn captured by En Passant was not found")
+                        ))
+                    }
                 }
         }
 
@@ -543,7 +551,9 @@ impl Board {
                 },
                 None => {
                     self.print();
-                    panic!("{:?} is malformed: source piece not found", mov);
+                    return Err(MakeMoveError::PieceNotFound(
+                            String::from("Source piece not found")
+                    ))
                 }
             };
 
@@ -617,7 +627,7 @@ impl Board {
         self.ply += 1;
         self.hash ^= self.zobrist_seed[780];
 
-        captured_piece
+        Ok(captured_piece)
     }
 
     /// Completely reverse make_move as if it never happened