[gnugo-devel] Crash in 3.4

[Gunnar Farneback]

I encountered a crash in GNU Go 3.4, when running a twogtp match
against Wally. The game is with 31 handicap stones and the game record
is appended. Loading the end position recreates the crash. The problem
is with pattern EE601 which causes a cyclic replacement assertion in
the crashing position.

This could of course have been avoided if we had remembered to turn
off that assertion for the stable release, as we did for 3.2. However,
I'm not convinced that this particular problem is likely to occur in a
game against a reasonable opponent.

Btw, the twogtp match, using handicap adjustment after every game,
seems to indicate that proper handicap between GNU Go 3.4 and Wally is
about 30 stones.

/Gunnar

(;
GM[1]FF[4]
SZ[19]HA[31]KM[0.5]
AB[cc][mc][qc][dd][gd][jd][pd][me][gf][dg][mg][qg]
[gh][dj][gj][jj][pj][dm][fm][hm][jm][lm][nm][pm]
[dp][jp][mp][pp][cq][gq][qq]
PW[GNU Go 3.4 (random seed 844491980)]
PB[Wally 2.1 (random seed unknown)]
RU[Japanese]
RE[Void]
GC[Engine `../gnugo --quiet --mode gtp --chinese-rules' playing white
crashed!]
;W[gc];B[og];W[ib];B[nf];W[fc];B[fd];W[ec];B[ed];W[kc];B[jb];W[jc];B[ic]
;W[hc];B[id];W[kb];B[hb];W[ja];B[hd];W[na];B[mi];W[db];B[cb];W[ca];B[ba]
;W[da];B[nh];W[pa];B[ig];W[ra];B[kg];W[rc];B[rd];W[rb];B[qb];W[qa];B[lh]
;W[sd];B[se];W[re];B[sc];W[oc];B[qe];W[kd];B[rf];W[ke];B[pf];W[od];B[oe]
;W[pb];B[nd];W[pc];B[qd];W[mb];B[lf];W[lc];B[la];W[nc];B[md];W[sb];B[sd]
;W[je];B[lb];W[ie];B[ob];W[he];B[ge];W[hf];B[hg];W[jf];B[ef];W[jg];B[fg]
;W[jh];B[fe];W[ki];B[mk];W[ih];B[ha];W[ij];B[ia];W[jb];B[eh];W[ji];B[fi]
;W[hk];B[hi];W[ii];B[hh];W[jk];B[kj];W[kk];B[lj];W[gk];B[li];W[fk];B[il]
;W[ik];B[nj];W[dk];B[oi];W[ck];B[ph];W[ej];B[ei];W[di];B[cj];W[ci];B[bj]
;W[bi];B[fj];W[ek];B[aj];W[cm];B[in];W[bk];B[ok];W[cf];B[nl];W[dn];B[em]
;W[co];B[bn];W[bo];B[cn];W[do];B[cl];W[bm];B[bl];W[am];B[al];W[an];B[ak]
;W[dl];B[bp];W[cp];B[bq];W[fo];B[en];W[eo];B[dq];W[ho];B[ap];W[hq];B[de]
;W[gp];B[gn];W[fq];B[gr];W[fr];B[ep];W[cs];B[fp];W[bs];B[go];W[hp];B[fn]
;W[jr];B[hn];W[lr];B[mr];W[lq];B[lp];W[nr];B[mq];W[ms];B[er];W[es];B[eq]
;W[fs];B[gs];W[ds];B[kq];W[kr];B[gl];W[pr];B[qr];W[be];B[bd];W[qs];B[rs]
;W[ps];B[ce];W[bf];B[df];W[jq];B[kp];W[rr];B[rq];W[ss];B[bg];W[cg];B[ch]
;W[bh];B[dh];W[ai];B[af];W[ag];B[bl];W[bb];B[bc];W[aa];B[al];W[io];B[jo]
;W[nq];B[np];W[oq];B[os];W[op];B[kn];W[pq];B[cj];W[qp];B[po];W[qo];B[bj]
;W[qn];B[ak];W[rl];B[oo];W[rj];B[pn];W[rh];B[rm];W[qm];B[ro]
;C[Engine `../gnugo --quiet --mode gtp --chinese-rules' playing white
crashed!]
)