commit 32be30224703df053be11d1c953763e7d7f2a5f6
from: Stefan Sperling <stsp@stsp.name>
date: Tue Sep 22 22:11:55 2020 UTC

do not clobber the arraylist head if recallocarray fails

commit - dabc100859385b31dcfbe62d04187d6947a12795
commit + 32be30224703df053be11d1c953763e7d7f2a5f6
blob - bb6e626bf9c86e3fa8598f4710496f81737f2c17
blob + badedfc28278523e489b303c0c470e925bbbabfa
--- include/diff/arraylist.h
+++ include/diff/arraylist.h
@@ -40,6 +40,7 @@
 #define ARRAYLIST(MEMBER_TYPE) \
 	struct { \
 		MEMBER_TYPE *head; \
+		MEMBER_TYPE *p; \
 		unsigned int len; \
 		unsigned int allocated; \
 		unsigned int alloc_blocksize; \
@@ -61,12 +62,18 @@
 		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
 			(ARRAY_LIST).allocated += \
 				(ARRAY_LIST).alloc_blocksize ? : 8; \
-			(ARRAY_LIST).head = recallocarray((ARRAY_LIST).head, \
+			(ARRAY_LIST).p = recallocarray((ARRAY_LIST).head, \
 				(ARRAY_LIST).len, \
 				(ARRAY_LIST).allocated, \
 				sizeof(*(ARRAY_LIST).head)); \
+			if ((ARRAY_LIST).p == NULL) { \
+				NEW_ITEM_P = NULL; \
+				break; \
+			} \
+			(ARRAY_LIST).head = (ARRAY_LIST).p; \
+			(ARRAY_LIST).p = NULL; \
 		}; \
-		if (!(ARRAY_LIST).head \
+		if ((ARRAY_LIST).head == NULL \
 		    || (ARRAY_LIST).allocated < (ARRAY_LIST).len + 1) { \
 			NEW_ITEM_P = NULL; \
 			break; \