PHP 8 no longer silently ignores fatal errors. Background processing of profile pictures in our self-hosted instance was failing on system\Images\Gd.php line 224, which throws a fatal error on imagecolorsforindex if the computed transparency index of a GIF is outside the color range of the image. Fortunately, someone else document a fix at https://github.com/processwire/processwire-issues/issues/1299, which worked (after substituting variable names):
// Suggested by https://github.com/processwire/processwire-issues/issues/1299
$transcol = $transindex != -1 ? @imagecolorsforindex($this->image, ($transindex < imagecolorstotal($this->image) ? $transindex : $transindex - 1)) : 0;
// $transcol = @imagecolorsforindex( $this->image, $transindex );
My mod team reports alerts are not being seen if an end date is set, even if the end date is in the future. Changing the end date to None allows the alert to display correctly.
Rodrigo Castillo got a reaction from SeNioR- in Bug with Gd handling of transparent GIFs with PHP 8.0+
