Check for spprintf failure in key generation

Add a check for negative length returned by spprintf to ensure key generation doesn't proceed with invalid data. This prevents potential issues or crashes that could occur if the function fails and returns an error.

rayaop.c

@@ -106,6 +106,9 @@ PHP_RAYAOP_API char *php_rayaop_generate_key(zend_string *class_name, zend_strin
     }
     char *key;
     int len = spprintf(&key, 0, "%s::%s", ZSTR_VAL(class_name), ZSTR_VAL(method_name));
+    if (len < 0) {
+        return NULL;
+    }
     if (key_len) {
         *key_len = (size_t)len;
     }