ref: 843d4ca17def11671809786f2a5aebd75f230dd9
parent: 15f4fa851a5781cf77984a6046405ffa758e7b33
author: Ben Harris <bjh21@bjh21.me.uk>
date: Fri Feb 3 15:52:05 EST 2023
Tolerate incorrect solutions in Inertia
The "solve" operation in Inertia generates a proposed solution as a
move string. But if such a move string is loaded from a save file it
might not actually describe a solution. If that happens then it's
possible to reach the end of the "solution" without winning, and doing
so should probably cause a recalculation of the solution rather than
an assertion failure ("execute_move: Assertion `ret->solnpos <
ret->soln->len' failed.").
I am a little concerned by the way that normal solve operations end up
encoded in the save file, but the re-solvings caused by going off
course don't, but I haven't got a good answer to that.
Here's a save file that demonstrates the assertion failure:
SAVEFILE:41:Simon Tatham's Portable Puzzle Collection
GAME :7:Inertia
PARAMS :3:8x8
CPARAMS :3:8x8
DESC :64:sbgwsmswwgggwggmmbwgwbssbwbsbwbbwsSmwbbsbbmggbmssgmgwbmmwmbmmwsw
NSTATES :2:3
STATEPOS:1:1
MOVE 000:2:S0
MOVE 000:2:00
--- a/inertia.c
+++ b/inertia.c
@@ -1741,11 +1741,10 @@
if (ret->soln) {if (ret->dead || ret->gems == 0)
discard_solution(ret);
- else if (ret->soln->list[ret->solnpos] == dir) {+ else if (ret->soln->list[ret->solnpos] == dir &&
+ ret->solnpos+1 < ret->soln->len)
++ret->solnpos;
- assert(ret->solnpos < ret->soln->len); /* or gems == 0 */
- assert(!ret->dead); /* or not a solution */
- } else {+ else {const char *error = NULL;
char *soln = solve_game(NULL, ret, NULL, &error);
if (!error) {