Pour obtenir une clé
d'essai remplissez le formulaire ci-dessous
Demandez des tariffs
Nouvelle licence
Renouvellement de licence
--Sélectionnez la devise--
USD
EUR
RUB
* En cliquant sur ce bouton, vous acceptez notre politique de confidentialité

Free PVS-Studio license for Microsoft MVP specialists
To get the licence for your open-source project, please fill out this form
** En cliquant sur ce bouton, vous acceptez notre politique de confidentialité.

I am interested to try it on the platforms:
** En cliquant sur ce bouton, vous acceptez notre politique de confidentialité.

Votre message a été envoyé.

Nous vous répondrons à


Si vous n'avez toujours pas reçu de réponse, vérifiez votre dossier
Spam/Junk et cliquez sur le bouton "Not Spam".
De cette façon, vous ne manquerez la réponse de notre équipe.

>
>
>
V3180. The 'HasFlag' method always retu…
Analyzer diagnostics
General Analysis (C++)
General Analysis (C#)
General Analysis (Java)
Diagnosis of micro-optimizations (C++)
Diagnosis of 64-bit errors (Viva64, C++)
Customer specific requests (C++)
MISRA errors
AUTOSAR errors
OWASP errors (C#)
Problems related to code analyzer
Additional information
Contents

V3180. The 'HasFlag' method always returns 'true' because the value '0' is passed as its argument.

07 Sep 2022

The analyzer has detected the call of the 'HasFlag' method, that always returns 'true' because the argument value is '0'.

Let's look at the following example:

public enum RuntimeEvent
{
  Initialize = 1,
  BeginRequest = 2,
  BeginSessionAccess = 4,
  ExecuteResource = 8,
  EndSessionAccess = 16,
  EndRequest = 32
}

public void FlagsTest()
{
  ....
  RuntimeEvent support = GetSupportEvent();
  ....
  Assert.True(support.HasFlag(  RuntimeEvent.EndRequest
                              & RuntimeEvent.BeginRequest),
              "End|Begin in End|SessionEnd");
  ....
}

'support' is an enumeration instance of the 'RuntimeEvent' type. The variable gets the value after the 'GetSupportEvent' method is called. After initialization, 'support' is checked for the flag with a bitwise 'AND' value for 'EndRequest' and 'BeginRequest'.

A check like this makes no sense, because the expression '32 & 2' is zero. If the 'HasFlag' argument is zero, the result of the method call is always 'true'. Therefore, the test passes regardless of the 'support' value. Such code looks suspicious.

The correct version of the check might look as follows:

public void FlagsTest()
{
  ....
  RuntimeEvent support = GetSupportEvent();
  ....
  Assert.True(support.HasFlag(  RuntimeEvent.EndRequest 
                              | RuntimeEvent.BeginRequest),
              "End|Begin in End|SessionEnd");
  ....
}
Unicorn with delicious cookie
Nous utilisons des cookies pour améliorer votre expérience de navigation. En savoir plus
Accepter