From 6906c3431988978802ccfe2daef093a3ba31e9a8 Mon Sep 17 00:00:00 2001
From: Omar Chebib <omar.chebib@espressif.com>
Date: Mon, 8 Aug 2022 15:39:25 +0800
Subject: [PATCH] heap: add a unit test for malloc(0) and slightly optimize
 heap_caps_malloc_prefer

---
 components/heap/heap_caps.c        |  2 +-
 components/heap/test/test_malloc.c | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/components/heap/heap_caps.c b/components/heap/heap_caps.c
index 19e45cfa6e..f3ac9460ee 100644
--- a/components/heap/heap_caps.c
+++ b/components/heap/heap_caps.c
@@ -267,7 +267,7 @@ IRAM_ATTR void *heap_caps_malloc_prefer( size_t size, size_t num, ... )
     while (num--) {
         caps = va_arg( argp, uint32_t );
         r = heap_caps_malloc_base( size, caps );
-        if (r != NULL) {
+        if (r != NULL || size == 0) {
             break;
         }
     }
diff --git a/components/heap/test/test_malloc.c b/components/heap/test/test_malloc.c
index 6f4bbd8728..995a64da33 100644
--- a/components/heap/test/test_malloc.c
+++ b/components/heap/test/test_malloc.c
@@ -132,3 +132,25 @@ TEST_CASE("malloc(0) should return a NULL pointer", "[heap]")
     p = malloc(0);
     TEST_ASSERT(p == NULL);
 }
+
+static bool failure_occured = false;
+
+static void test_alloc_failure_callback(size_t size, uint32_t caps, const char * function_name)
+{
+    failure_occured = true;
+}
+
+TEST_CASE("malloc/calloc(0) should not call failure callback", "[heap]")
+{
+    void* ptr = NULL;
+    esp_err_t ret = heap_caps_register_failed_alloc_callback(test_alloc_failure_callback);
+    TEST_ASSERT(ret == ESP_OK);
+    ptr = malloc(0);
+    TEST_ASSERT_NULL(ptr);
+    /* Check that our callback was NOT called */
+    TEST_ASSERT_FALSE(failure_occured);
+    /* Do the same thing for calloc */
+    ptr = calloc(0, 0);
+    TEST_ASSERT_NULL(ptr);
+    TEST_ASSERT_FALSE(failure_occured);
+}