knownConditionTrueFalse False Positive

[Steve Albright]

I think it might be considering the isNull check and because not null it thinks it has content but they are two different things.

style: knownConditionTrueFalse - Condition '!sourceFilePath.isEmpty()' is always true

bool Example(const QString& sourceFilePath, const QUuid& rowMapErid)
{
   bool success = false;
   if(not sourceFilePath.isNull() and not sourceFilePath.isEmpty() and not rowMapErid.isNull())
   {
      success = CopyFile(sourceFilePath, rowMapErid);
   }

   return success;
}

[CHR]

https://doc.qt.io/qt-6/qstring.html#isNull doesn't explain the difference, except mentioning "historical reasons". So why have both checks?

[Steve Albright]

This is the key difference

QString("").isNull(); // returns false

QString().isEmpty(); // returns true
QString("").isEmpty(); // returns true

[CHR]

I have created https://trac.cppcheck.net/ticket/12776