Fix bug where deserializing nullpointers as functions failed instead of returning nil

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
 

src/clj/coffi/ffi.clj

@@ -367,13 +367,14 @@
 
 (defmethod mem/deserialize* ::fn
   [addr [_fn arg-types ret-type & {:keys [raw-fn?]}]]
+  (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))))
+            (not raw-fn?) (make-serde-wrapper arg-types ret-type)))))
 
 ;;; Static memory access