Missed always true situation

[Steve Albright]

I was told clazy caught this, tried with cppcheck 2.6 and it passed so there might be an opportunity to make the tool better.

I checked and confirmed that enum1 and enum2 were not equal so therefore mode can't be equal to both so the or is always true.

if((mode != enum1 || mode != enum2) && !SomeBooleanFunction())

[Daniel Marjamäki]

can you please provide a proper example code. with this code I get a warning:

enum class Mode { enum1, enum2 };

void foo(Mode mode) {
    if((mode != enum1 || mode != enum2) && !SomeBooleanFunction()) {}
}

[Daniel Marjamäki]

1.cpp:5:23: warning: Logical disjunction always evaluates to true: mode != 0 || mode != 1. [incorrectLogicOperator]
    if((mode != enum1 || mode != enum2) && !SomeBooleanFunction()) {}
                      ^

[Steve Albright]

OK, this was hard to reproduce but I finally did but it required me to put the enum definition in a different header file instead (which happens to be referenced as ProjectName/HeaderFile.h in the cpp file and is in a completely different location so this could be a case of cppcheck not finding the path that we have managed with CMake to keep our source compiling.

The Header (say path is sourceDir/OtherFolder/ProjectName/Example.h)

enum ExampleEnum
{
   val1 = 0,
   val2,
   val3
};

The CPP The Header (say path is sourceDir/ProjectName/Example.cpp)

void Example(ExampleEnum exampleEnumValue)
{
   if(exampleEnumValue != val1 || exampleEnumValue != val3)
   {
      // clazy knows the paths better and gives the warning that there are overlapping conditions so there is an always true
   }
}

Maybe I need to figure out how to set paths better in CPPCheck or it could/should scan cmake better?

[Daniel Marjamäki]

yes it sounds like a include path problem.. does it work better if you generate and load a compile database. cppcheck --project=compile_commands.json

[Steve Albright]

I tried that and it still didn't find this issue but I did find others to look into...