[CodingStyle] IdenticalFalseToBooleanNotRector applies on bool|null

[gnutix]

Subject	Details
Rector version	0.6.x-dev@9a330e2
PHP version	unknown (inside Docker)
Full Command	docker run --rm -v $(pwd):/app rector_phar process --ansi --autoload-file /app/vendor/autoload.php --config /app/rector.yaml /app/vendor-unmanaged/gammadia/moment/src/Period.php --dry-run

Current Behaviour

1) src/SomeFile.php

    ---------- begin diff ----------
--- Original
+++ New
@@ -66,13 +66,13 @@
        $start = !empty($startStr)
            ? ($startStr[0] === 'P' ? false : \DateTimeImmutable::createFromISOString($startStr, $timezone))
            : null;
        $end = !empty($endStr)
             ? ($endStr[0] === 'P' ? false : \DateTimeImmutable::createFromISOString($endStr, $timezone))
             : null;

-        if (false === $end && $start) {
+        if (!$end && $start) {
             $end = $start->add(new \DateInterval($endStr));
-        } elseif (false === $start && $end) {
+        } elseif (!$start && $end) {
             $start = $end->sub(new \DateInterval($startStr));
         }

-        if ($start === false || $end === false) {
+        if (!$start || !$end) {
             throw new InvalidArgumentException(sprintf('Invalid ISO period "%s"', $period));
         }
    ----------- end diff -----------

Applied rules:

 * Rector\CodeQuality\Rector\Class_\CompleteDynamicPropertiesRector
 * Rector\CodingStyle\Rector\Identical\IdenticalFalseToBooleanNotRector
 * Rector\CodeQuality\Rector\If_\RemoveAlwaysTrueConditionSetInConstructorRector
 * Rector\DeadCode\Rector\ClassMethod\RemoveOverriddenValuesRector
 * Rector\DeadCode\Rector\FunctionLike\RemoveCodeAfterReturnRector
 * Rector\Rector\Argument\ArgumentRemoverRector
 * Rector\CodingStyle\Rector\ClassMethod\ReturnArrayClassMethodToYieldRector
 * Rector\Renaming\Rector\Annotation\RenameAnnotationRector
 * Rector\Rector\Argument\ArgumentDefaultValueReplacerRector
 * Rector\Rector\Argument\ArgumentAdderRector
 * Rector\Rector\ClassMethod\WrapReturnRector

This change breaks the code, as null now passes the !$var test, where it should only be false that does.

Minimal PHP Code Causing Issue

<?php 
function someFunction(string $startStr, string $endStr)
{
        $start = !empty($startStr)
            ? ($startStr[0] === 'P' ? false : \DateTimeImmutable::createFromISOString($startStr, $timezone))
            : null;
        $end = !empty($endStr)
            ? ($endStr[0] === 'P' ? false :  \DateTimeImmutable::createFromISOString($endStr, $timezone))
            : null;

        if (false === $end && $start) {
            $end = $start->add(new \DateInterval($endStr));
        } elseif (false === $start && $end) {
            $start = $end->sub(new \DateInterval($startStr));
        }

        if ($start === false || $end === false) {
            throw new InvalidArgumentException(sprintf('Invalid ISO period "%s"', $period));
        }

       // ...
}

Expected Behaviour

Nothing should change, as $start and $end can be both bool or null values.

[TomasVotruba]

Thanks for easy to understand and descriptive report with all the needed test data 👍