Breaking: #99898 - Continuous array keys from GeneralUtility::intExplode

See forge#99898

Description

When the method \TYPO3\CMS\Core\Utility\GeneralUtility::intExplode() is called with the parameter $removeEmptyEntries set to true, the array keys are now continuous.

Previously, the array had gaps in the keys in the places where empty values were removed. This behavior had been an undocumented side-effect of the implementation. It is now changed to always return an array with continuous integer array keys (i.e., a list) to reduce surprising behavior.

Before this change (TYPO3 v12):

GeneralUtility::intExplode(',', '1,,3', true);
// Result: [0 => 1, 2 => 3]

After this change (TYPO3 v13):

GeneralUtility::intExplode(',', '1,,3', true);
// Result: [0 => 1, 1 => 3]

Impact

Calling GeneralUtility::intExplode() with the parameter $removeEmptyEntries set to true and relying on gaps in the keys of the resulting array keys may lead to unexpected results.

Affected installations

Custom extensions that rely on the array keys of the result of GeneralUtility::intExplode() to have gaps in the keys.

Migration

Adapt your code to not rely on gaps in the keys anymore.