From f77d9a727059f2aece992176013db7467c045fd7 Mon Sep 17 00:00:00 2001
From: Bloop <13398309+vinylspiders@users.noreply.github.com>
Date: Sun, 19 Nov 2023 12:08:59 -0500
Subject: [PATCH] Fixes a race condition in mutations code (#79829)

## About The Pull Request

One of the timers has a callback to the `modify()` proc which also
doesn't check whether the mutation owner has been deleted since the
timer began, potentially resulting in a runtime.


![image](https://github.com/tgstation/tgstation/assets/13398309/1e41c48b-2620-4473-9278-702d490871cc)

## Why It's Good For The Game

Fixes bugs

## Changelog

:cl:
fix: fixed a race condition with mutations
/:cl:
---
 code/datums/mutations/_mutations.dm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/code/datums/mutations/_mutations.dm b/code/datums/mutations/_mutations.dm
index 9ea3c8dfb17..82e948ec44f 100644
--- a/code/datums/mutations/_mutations.dm
+++ b/code/datums/mutations/_mutations.dm
@@ -173,7 +173,7 @@
  * returns an instance of a power if modification was complete
  */
 /datum/mutation/human/proc/modify()
-	if(modified || !power_path || !owner)
+	if(modified || !power_path || QDELETED(owner))
 		return
 	var/datum/action/cooldown/modified_power = locate(power_path) in owner.actions
 	if(!modified_power)