Re: [PATCH RESEND] selftests: Suppress unused variable warning

[Shuah Khan <skhan@linuxfoundation.org>]

On 6/19/25 15:40, Shuah Khan wrote:
> On 6/19/25 13:00, John Hubbard wrote:
>> On 6/19/25 10:00 AM, Shuah Khan wrote:
>>> On 6/19/25 01:46, Chen Linxuan wrote:
>>>> On Thu, Jun 19, 2025 at 5:23 AM Shuah Khan <skhan@linuxfoundation.org> wrote:
>>>>> On 6/9/25 20:07, Chen Linxuan wrote:
>> ...
>>>>>> diff --git a/tools/testing/selftests/filesystems/mount-notify/mount- notify_test.c b/tools/testing/selftests/filesystems/mount-notify/ mount-notify_test.c
>>>>>> index 63ce708d93ed0..34afe27b7978f 100644
>>>>>> --- a/tools/testing/selftests/filesystems/mount-notify/mount- notify_test.c
>>>>>> +++ b/tools/testing/selftests/filesystems/mount-notify/mount- notify_test.c
>>>>>> @@ -465,7 +465,9 @@ TEST_F(fanotify, rmdir)
>>>>>>        ASSERT_GE(ret, 0);
>>>>>>
>>>>>>        if (ret == 0) {
>>>>>> -             chdir("/");
>>>>>> +             // Suppress -Wunused-result
>>>>>> +             // Ref: https://gcc.gnu.org/bugzilla/show_bug.cgi? id=66425#c34
>>>>>> +             (void) !chdir("/");
>>
>> This is quite ugly. :)
>>
>>>>>>> Why not fix the problem the right way by checking the return value.
>>>>> Suppressing the error isn't useful.
>>>>
>>>> The code is already handling cleanup in error cases,
>>>> and I don't think checking the result of chdir would be useful here.
>>>
>>
>> Why not just fail with the appropriate test result, if chdir() fails
>> here, instead of making a bit of a mess with odd void casts to a
>> negated return value, and a reference to a compiler bug report?
>>
>> Really, Shuah is putting you on the right path here.
> 
> Ha. I didn't ask to suppress the error with the cast. I asked
> to check the return and fail.
> 
>>

Sorry John. I didn't read it correctly the first time.
I probably go get more coffee. :)

thanks,
-- Shuah