From d99a24843b4fbb9ab7f1b5b493d04e7350d2d5af Mon Sep 17 00:00:00 2001
From: nhmall <nhmall@nethack.org>
Date: Mon, 9 Dec 2024 21:41:26 -0500
Subject: [PATCH] deal with light sources in discard_migrations()

Otherwise, when discard_migrations() purges monsters,
their stale monster pointers can be left inside the light source data
structure.
---
 src/dog.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/dog.c b/src/dog.c
index 607f2cdf8..c4e4b60e7 100644
--- a/src/dog.c
+++ b/src/dog.c
@@ -914,6 +914,8 @@ discard_migrations(void)
             mtmp->nmon = 0;
             discard_minvent(mtmp, FALSE);
             /* bypass mongone() and its call to m_detach() plus dmonsfree() */
+            if (emits_light(mtmp->data))
+                del_light_source(LS_MONSTER, monst_to_any(mtmp));
             dealloc_monst(mtmp);
         }
     }