These two array allocations have several minor flaws:

  - they use bare malloc, rather than our error-checking

  - they do a bare multiplication to determine the total
    size (which in theory can overflow, though in this case
    the sizes are all constants)

  - they use sizeof(type), but the type in the second one
    doesn't match the actual array (though it's "int" versus
    "unsigned int", which are guaranteed by C99 to have the
    same size)

None of these are likely to be problems in practice, and
this is just a test helper. But since people often look at
test helpers as reference code, we should do our best to
model the recommended techniques.

Switching to ALLOC_ARRAY fixes all three.

Signed-off-by: Jeff King <>
The sizeof() thing came from Code AI's original email. I'm happy to
include a Reported-by there, but I wasn't sure of the correct entity to
credit. :)

 t/helper/test-hashmap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/t/helper/test-hashmap.c b/t/helper/test-hashmap.c
index 1145d51671..b36886bf35 100644
--- a/t/helper/test-hashmap.c
+++ b/t/helper/test-hashmap.c
@@ -85,8 +85,8 @@ static void perf_hashmap(unsigned int method, unsigned int 
        unsigned int *hashes;
        unsigned int i, j;
-       entries = malloc(TEST_SIZE * sizeof(struct test_entry *));
-       hashes = malloc(TEST_SIZE * sizeof(int));
+       ALLOC_ARRAY(entries, TEST_SIZE);
+       ALLOC_ARRAY(hashes, TEST_SIZE);
        for (i = 0; i < TEST_SIZE; i++) {
                snprintf(buf, sizeof(buf), "%i", i);
                entries[i] = alloc_test_entry(0, buf, strlen(buf), "", 0);

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