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jazzyb / libforchess

A chess engine for the "ultimate social game".
GNU General Public License v3.0
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Assertion Fails in fc_get_pawn_moves() #14

Closed jazzyb closed 12 years ago

jazzyb commented 12 years ago

In commit d746891b63ef6c595c3aa641fc6066fd4dd52109.

The example program when run with the parameters -d 4 2 4 results in a segfault for the moves (1: d1-e1 a5-a4 e5-e4 h4-h5).

The following GDB output shows that an assertion is failing in fc_get_pawn_moves() where the program can't find the orientation of a particular pawn.

libforchess.git$ gdb ./a.out
GNU gdb 6.3.50-20050815 (Apple version gdb-1515) (Sat Jan 15 08:33:48 UTC 2011)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
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This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared libraries ... done

(gdb) run -d 4 2 4
Starting program: /Users/jazzyb/src/libforchess.git/a.out -d 4 2 4
Reading symbols for shared libraries ++. done
1:  d1-e1   :: 0s
2: warning: this program uses gets(), which is unsafe.
a5-a4
3:  e5-e4   :: 0s
4: h4-h5
Assertion failed: (0), function fc_get_pawn_moves, file src/board.c, line 460.

Program received signal SIGABRT, Aborted.
0x00007fff8329b0b6 in __kill ()
(gdb) where
#0  0x00007fff8329b0b6 in __kill ()
#1  0x00007fff8333b9f6 in abort ()
#2  0x00007fff833289bc in __assert_rtn ()
#3  0x00000001000074bb in fc_get_pawn_moves (board=0x100809900, moves=0x100100180, player=FC_FOURTH) at src/board.c:460
#4  0x0000000100007d29 in fc_board_get_moves (board=0x100809900, moves=0x100100180, player=FC_FOURTH) at src/board.c:701
#5  0x00000001000056ff in alphabeta (ai=0x7fff5fbfde90, ret=0x0, player=FC_FOURTH, depth=1, alpha=-50, beta=2147483647, max=0) at src/ai.c:163
#6  0x0000000100005904 in move_and_adjust_scores (mv=0x100802190, ai=0x7fff5fbfde90, ret=0x0, player=FC_THIRD, depth=2, alpha=0x7fff5fbfdb84, beta=0x7fff5fbfdb80, max=1) at src/ai.c:217
#7  0x00000001000057d9 in alphabeta (ai=0x7fff5fbfde90, ret=0x0, player=FC_THIRD, depth=2, alpha=-50, beta=2147483647, max=1) at src/ai.c:185
#8  0x0000000100005904 in move_and_adjust_scores (mv=0x100804800, ai=0x7fff5fbfde90, ret=0x0, player=FC_SECOND, depth=3, alpha=0x7fff5fbfdc84, beta=0x7fff5fbfdc80, max=0) at src/ai.c:217
#9  0x00000001000057d9 in alphabeta (ai=0x7fff5fbfde90, ret=0x0, player=FC_SECOND, depth=3, alpha=-2147483648, beta=2147483647, max=0) at src/ai.c:185
#10 0x0000000100005904 in move_and_adjust_scores (mv=0x100807028, ai=0x7fff5fbfde90, ret=0x7fff5fbfde60, player=FC_FIRST, depth=4, alpha=0x7fff5fbfdd84, beta=0x7fff5fbfdd80, max=1) at src/ai.c:217
#11 0x00000001000057d9 in alphabeta (ai=0x7fff5fbfde90, ret=0x7fff5fbfde60, player=FC_FIRST, depth=4, alpha=-2147483648, beta=2147483647, max=1) at src/ai.c:185
#12 0x0000000100005e29 in fc_ai_next_move (ai=0x7fff5fbfde90, ret=0x7fff5fbfde60, player=FC_FIRST, depth=4, seconds=0) at src/ai.c:362
#13 0x000000010000139f in make_computer_move (game=0x7fff5fbfdfe0, player=FC_FIRST, depth=4, timeout=0) at examples/cli/simple.c:205
#14 0x000000010000104f in main (argc=5, argv=0x7fff5fbfe040) at examples/cli/simple.c:120
(gdb)
jazzyb commented 12 years ago

The issue was in fc_game_convert_coords_to_move() in game.c. I had forgotten to update the game API to account for opp_player and opp_piece being added to the move struct. This has been broken for a really long time without me noticing anything. I really need to (1) perform better validation testing before any major commits (simply running ./a.out and not seeing a crash won't do it anymore) and (2) revamp or completely get rid of the game API -- it is complete trash and the one part of this library which isn't relatively well-written.