From 63eb1114892070a82da04d2659f8985f4763c085 Mon Sep 17 00:00:00 2001
From: Oran Agra <oran@redislabs.com>
Date: Wed, 21 Feb 2018 11:04:13 +0200
Subject: [PATCH] Fix zrealloc to behave similarly to je_realloc when size is 0

According to C11, the behavior of realloc with size 0 is now deprecated.
it can either behave as free(ptr) and return NULL, or return a valid pointer.
but in zmalloc it can lead to zmalloc_oom_handler and panic.
and that can affect modules that use it.

It looks like both glibc allocator and jemalloc behave like so:
  realloc(malloc(32),0) returns NULL
  realloc(NULL,0) returns a valid pointer

This commit changes zmalloc to behave the same
---
 src/zmalloc.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/zmalloc.c b/src/zmalloc.c
index 094dd80fa..01ac8c797 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -147,6 +147,10 @@ void *zrealloc(void *ptr, size_t size) {
     size_t oldsize;
     void *newptr;
 
+    if (size == 0 && ptr!=NULL) {
+        zfree(ptr);
+        return NULL;
+    }
     if (ptr == NULL) return zmalloc(size);
 #ifdef HAVE_MALLOC_SIZE
     oldsize = zmalloc_size(ptr);