Fix: prevent segfault for non-existent trap.

Caught this while fuzzing. Fix comes from NetHack 3.7 commit 5615974, slightly modified plus some other improvements in this block of code.
k21971 · Mar 12, 2025 · 27a4d7f · 27a4d7f
1 parent 4b0dd73
commit 27a4d7f
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diff --git a/doc/evilhack-changelog.md b/doc/evilhack-changelog.md
@@ -4383,4 +4383,5 @@ The following changes to date are:
   'output' used (windows build, crafting traps)
 - Debug hints files tweak
 - Fix: get rid of unneeded dispose_of_orig_obj() call
+- Fix: prevent segfault for non-existent trap
 
diff --git a/src/do.c b/src/do.c
@@ -2306,12 +2306,16 @@ struct obj *corpse;
                     struct trap *ttmp;
 
                     ttmp = t_at(mtmp->mx, mtmp->my);
-                    ttmp->tseen = TRUE;
+                    if (ttmp)
+                        ttmp->tseen = TRUE;
                     pline("%s claws its way out of the ground!",
-                          Amonnam(mtmp));
+                          canspotmon(mtmp) ? Amonnam(mtmp) : Something);
                     newsym(mtmp->mx, mtmp->my);
-                } else if (distu(mtmp->mx, mtmp->my) < 5 * 5)
-                    You_hear("scratching noises.");
+                } else if (distu(mtmp->mx, mtmp->my) < 5 * 5) {
+                    if (!Deaf)
+                        You_hear("scratching noises.");
+                }
+                fill_pit(mtmp->mx, mtmp->my);
                 break;
             }
             /*FALLTHRU*/