[cfe-dev] [RFC][PATCH] Static analyser warning about identical inner condition

[Daniel Marjamäki]

Hello!

This is just a request for comments.

The patch I attach improves the identicalexpr checker in the static analyser. It adds a warning when there is an identical inner condition inside a if.

Example code taken from a debian project:

        if(revint)
        {
            if(revint)

Testing:
I scanned 477 debian projects with this checker and got 2 warnings. Both are bugs as far as I see. Also, in both these cases the inner conditions does not have an 'else' so there is no unreachable code.

I think it would be a good idea to add a heuristic to avoid warnings when there is hidden code. For example:

    if (x)
    {
#if SOME_FALSE_CONDITION
        x = dostuff();
#endif
        if (x)

But other than that... this checker seems to be reliable imho.


A possible further improvement would be to warn also warn if the inner condition "overlaps". For instance:

    if (x == 15)
    {
        if (x > 0)
        ...

Any opinions / ideas?

Best regards,
Daniel Marjamäki

..................................................................................................................
Daniel Marjamäki Senior Engineer
Evidente ES East AB  Warfvinges väg 34  SE-112 51 Stockholm  Sweden

Mobile:                 +46 (0)709 12 42 62
E-mail:                 Daniel.Marjamaki at evidente.se

www.evidente.se
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