Test "if" condition usefuleness

[kubawerlos]

Would it make sense to test if the if condition is useful?

The mutation would be:

-if ($foo) {
+if (true || $foo) {
     return 1;
 }
 return 3;

[maks-rafalko]

Are you saying only about cases when variable (not negated) is used in an if statement?

because, we already have other mutators that do

- if (! $var)
+ if ($var)

- if ($var === 1)
+ if ($var !== 1)

...

If yes, then probably makes sense, but we will definitely need to analyze the results of this mutator (how many mutants are created / escaped / killed) to understand if it's useful one or not

[kubawerlos]

No, not only, in general test "if" condition.

Maybe better example would be with with return false.

The real life scenario would be some validator like this:

function isValid($a, $b, $c)
{
    if ($a || someGlobalFunction($a)) {
        return true;
    }
    if ($b) {
        return false;
    }
    if ($c) {
        return true;
    }
    return false;
}

and adding false && (...) to the condition (not true || as my first post - but maybe both mutation make sense) would verify if each condition is useful because maybe the other ifs handle all tests cases.

we will definitely need to analyze the results of this mutator

Is there any good practise flow for that? Or do you mean writing the mutator and running it in some "random" repositories and see the output?

[maks-rafalko]

This one is probably related to #243

Is there any good practise flow for that? Or do you mean writing the mutator and running it in some "random" repositories and see the output?

You can see e.g. #1215 (comment) - there is a table with stats that can be generated by perMutator logger, see https://infection.github.io/guide/usage.html