Pointer and reference local variables should be "const" if the corresponding object is not modified

franz_at_zasso · November 27, 2021, 5:00pm

Hi,
my code looks like this:

esp_err_t iot_button_set_evt_cb(button_handle_t btn_handle, button_cb_type_t type, button_cb cb, const void* arg)
{
    POINT_ASSERT(TAG, btn_handle, ESP_ERR_INVALID_ARG) //no semicolon, because Macro.
	button_dev_t* btn = (button_dev_t*) btn_handle;
    if (type == BUTTON_CB_PUSH) {
        btn->tap_psh_cb.arg = arg;
        btn->tap_psh_cb.cb = cb;

you can find it there:

github.com

espressif/esp-idf/blob/master/examples/bluetooth/esp_ble_mesh/common_components/button/button.c

// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include <stdio.h>
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "freertos/timers.h"
#include "esp_log.h"
#include "driver/gpio.h"

This file has been truncated. show original

Sonar tells me:
Make the type of this variable a pointer-to-const. The current type of “btn” is “struct button_dev *”.
BUT,
btn-> makes writes to the btn which is intended.

making btn a pointer to -const does not make sense here.

how to solve ?

necto · December 7, 2021, 8:23am

Hello again @franz_at_zasso!

This looks like another potential false positive. It might be due to a parsing error (missing include file, non-standard syntax, etc.). You can see parsing errors by activating the debug log.
I didn’t succeed in reproducing the issue on my side so do you think you could create a small reproducer for it?
To generate a reproducer file:

Add the reproducer option to the scanner configuration:
sonar.cfamily.reproducer= "Full path to the button.c file"
Re-running the scanner should generate a file named sonar-cfamily.reproducer in the project folder.
Please share this file (I can send you a PM if you want to share it privately)

I’m looking forward to nail down this false positive!

necto · June 2, 2022, 9:39am

Hi @franz_at_zasso
Let me know if you still experience the issue, or I can close the topic.

system · July 4, 2022, 11:20am

This topic was automatically closed 7 days after the last reply. New replies are no longer allowed.

necto · July 4, 2022, 11:21am

@franz_at_zasso , I’m closing the topic. Feel free to open another one with additional information I requested if you are still encountering the issue.