Reference in foreach should be unset after loop

[BHSPitMonkey (Stephen Eisenhauer)]

SonarPHP should flag code which uses a reference in a foreach loop without unsetting that reference immediately after.

Noncompliant code:

foreach ($entries as &$entry) {
    $entry += 1;
}

Compliant code:

foreach ($entries as &$entry) {
    $entry += 1;
}
unset($entry);

External references:

• Rule implemented in PHP Inspections EA analysis tool: https://github.com/kalessil/phpinspectionsea/blob/master/src/main/java/com/kalessil/phpStorm/phpInspectionsEA/inspectors/forEach/AlterInForeachInspector.java
• https://schlueters.de/blog/archives/141-references-and-foreach.html
• https://alephnull.uk/call-unset-after-php-foreach-loop-values-passed-by-reference

Type: Bug

[Alexandre_Gigleux]

Hello Stephen,

Thanks for the suggestion. I created SONARPHP-822 to add it to SonarPHP.

Regards