From 148d048bc8e930776bdc1557693a7cd6ee199507 Mon Sep 17 00:00:00 2001
From: "sentry[bot]" <39604003+sentry[bot]@users.noreply.github.com>
Date: Mon, 1 Jun 2026 17:05:27 +0200
Subject: [PATCH] Fixes null.b_type error in handle_rejection (#22556)

* Please describe the intent of your changes in a clear fashion.
The `handle_rejection()` proc in `code/modules/organs/organ.dm` was
attempting to access `owner.dna.b_type` without first verifying that
`owner` or `owner.dna` were non-null. This could happen if an organ's
`process()` chain continued to tick after the organ had been detached
from its mob, leading to a runtime error.
This change adds an early return guard `if(!owner || !owner.dna) return`
at the beginning of the `handle_rejection()` proc. This prevents the
null dereference and aligns the proc's behavior with similar checks
found in `handle_germ_effects()`.
* Please make sure that, in the case of mapping changes, you include
images of these changes in the PR's description.
* Please make sure to mark your PR as wip or review required by making a
comment with !wip or !review required
* If you include sprites/sounds/... (assets) that you have not created
yourself specify the license and original author below.
* Ensure that you also credit them in the appropriate location /
changelog as specified in the contributor guidelines

### Asset Licenses
The following assets that **have not** been created by myself are
included in this PR:

| Path | Original Author | License |
| --- | --- | --- |
| icons/example.dmi | ExamplePerson (Example Station) | CC0 |


Fixes SERVER-PROD-CN

---------

Co-authored-by: sentry[bot] <39604003+sentry[bot]@users.noreply.github.com>
Co-authored-by: VMSolidus <evilexecutive@gmail.com>
---
 code/modules/organs/organ.dm                  | 36 ++++++++++---------
 .../hellfirejag-organ-transplant-runtime.yml  |  4 +++
 2 files changed, 23 insertions(+), 17 deletions(-)
 create mode 100644 html/changelogs/hellfirejag-organ-transplant-runtime.yml

diff --git a/code/modules/organs/organ.dm b/code/modules/organs/organ.dm
index d175fb42c53..19c1e52e860 100644
--- a/code/modules/organs/organ.dm
+++ b/code/modules/organs/organ.dm
@@ -251,23 +251,25 @@ INITIALIZE_IMMEDIATE(/obj/item/organ)
 
 /obj/item/organ/proc/handle_rejection()
 	// Process unsuitable transplants.
-	if(dna)
-		if(!rejecting)
-			if(blood_incompatible(dna.b_type, owner.dna.b_type, species, owner.species))
-				rejecting = 1
-		else
-			rejecting++ //Rejection severity increases over time.
-			if(rejecting % 10 == 0) //Only fire every ten rejection ticks.
-				switch(rejecting)
-					if(1 to 50)
-						germ_level++
-					if(51 to 200)
-						germ_level += rand(1,2)
-					if(201 to 500)
-						germ_level += rand(2,3)
-					if(501 to INFINITY)
-						germ_level += rand(3,5)
-						owner.reagents.add_reagent(/singleton/reagent/toxin, rand(1,2))
+	if(!owner || !owner.dna || !dna)
+		return
+
+	if(!rejecting && blood_incompatible(dna.b_type, owner.dna.b_type, species, owner.species))
+		rejecting = 1
+		return
+
+	rejecting++ //Rejection severity increases over time.
+	if(rejecting % 10 == 0) //Only fire every ten rejection ticks.
+		switch(rejecting)
+			if(1 to 50)
+				germ_level++
+			if(51 to 200)
+				germ_level += rand(1,2)
+			if(201 to 500)
+				germ_level += rand(2,3)
+			if(501 to INFINITY)
+				germ_level += rand(3,5)
+				owner.reagents.add_reagent(/singleton/reagent/toxin, rand(1,2))
 
 /obj/item/organ/proc/receive_chem(chemical as obj)
 	return 0
diff --git a/html/changelogs/hellfirejag-organ-transplant-runtime.yml b/html/changelogs/hellfirejag-organ-transplant-runtime.yml
new file mode 100644
index 00000000000..4d42a97ba84
--- /dev/null
+++ b/html/changelogs/hellfirejag-organ-transplant-runtime.yml
@@ -0,0 +1,4 @@
+author: Hellfirejag
+delete-after: True
+changes:
+  - bugfix: "Fixed a runtime error in organ rejection."