CODEWITHSUNDEEP
c#nullsonarqube
Artemis
Artemis

Reputation: 1

Sonarqube bug, "Change this condition so that it does not always evaluate to 'false'; some subsequent code is never executed". Whats wrong here?:

IAlarmDevice alarmDevice = null;
 if(alarmFlag == 
     AlarmFlags.Acknowledge
    {
      alarmDevice = new 
     Acknowledged Armed Ice("Alarm1", 
     alarm.AcknowledgeCycle);
    }
 else{
      alarmDevice = new 
    ResetAlarmDevice("Alarm1", 
    alarm.ResetCycle);
     }

if(alarmDevice == null)
{
 throw new ArgumentException("Could 
 not create an Alarm device");
}

In the above code, the alarmDevice will get assigned in the "else" block if not the "if" block. In case even after assignment the value of alarmDevice is null( say could not find the alarm with the name passed in the constructor), the null check "if(alarmDevice == null)" will handle it. I don't understand why Sonarqube says that it always evaluates to false? It may evaluate to true in case there is no alarmDevice with the alarm name string passed in the constructor in which case alarmDevice will remain null. What am I missing here? Is it a sonar false positive by any chance?

Upvotes: 0

Views: 3308

Answers (1)

nvoigt
nvoigt

Reputation: 77304

If you remove all the noise, this is what your code comes down to:

if(...)
{
  alarmDevice = new ...
}
else
{
  alarmDevice = new ...
}

There is just no way in C# that alarmDevice could possibly be null. Constructors cannot return null in C# and so there is no possibility left to not have an instance assigned to your variable.

Upvotes: 0

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