perf: Avoid zero-fill in redis_key_prefix

iliaal · michael-grunder · commit b9320359e890 · 2026-06-02T16:32:16.000-07:00
redis_key_prefix used ecalloc to allocate the prefixed-key buffer, then
immediately overwrote the entire allocation with two memcpy calls. The
zero-fill was wasted work on every keyed argument when a prefix is set.

Use emalloc and write the single trailing NUL explicitly.
diff --git a/library.c b/library.c
@@ -4483,9 +4483,10 @@ redis_key_prefix(RedisSock *redis_sock, char **key, size_t *key_len) {
     }
 
     ret_len = ZSTR_LEN(redis_sock->prefix) + *key_len;
-    ret = ecalloc(1 + ret_len, 1);
+    ret = emalloc(1 + ret_len);
     memcpy(ret, ZSTR_VAL(redis_sock->prefix), ZSTR_LEN(redis_sock->prefix));
     memcpy(ret + ZSTR_LEN(redis_sock->prefix), *key, *key_len);
+    ret[ret_len] = '\0';
 
     *key = ret;
     *key_len = ret_len;
