From ea53cfbdc2f03cfa88ffec3623ee7df7745846ab Mon Sep 17 00:00:00 2001
From: Joshua Suskalo <joshua@iris.tv>
Date: Thu, 30 Sep 2021 15:26:56 -0500
Subject: [PATCH] Fix bug where deserializing nullpointers as functions failed
 instead of returning nil

---
 CHANGELOG.md          |  1 +
 src/clj/coffi/ffi.clj | 15 ++++++++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 462474b..11068eb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file. This change
 
 ## [Unreleased]
 ### Fixed
+- Deserializing nullpointers as functions threw an exception
 - Upcall stubs with non-primitive arguments failed to compile
 - Upcall stubs had incorrect types
 
diff --git a/src/clj/coffi/ffi.clj b/src/clj/coffi/ffi.clj
index ed93bfc..c6558a0 100644
--- a/src/clj/coffi/ffi.clj
+++ b/src/clj/coffi/ffi.clj
@@ -367,13 +367,14 @@
 
 (defmethod mem/deserialize* ::fn
   [addr [_fn arg-types ret-type & {:keys [raw-fn?]}]]
-  (-> addr
-      (downcall-handle
-       (method-type arg-types ret-type)
-       (function-descriptor arg-types ret-type))
-      (downcall-fn arg-types ret-type)
-      (cond->
-        (not raw-fn?) (make-serde-wrapper arg-types ret-type))))
+  (when-not (mem/null? addr)
+    (-> addr
+        (downcall-handle
+         (method-type arg-types ret-type)
+         (function-descriptor arg-types ret-type))
+        (downcall-fn arg-types ret-type)
+        (cond->
+            (not raw-fn?) (make-serde-wrapper arg-types ret-type)))))
 
 ;;; Static memory access