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<?php $a = array(); $a[] = 1; var_dump(array_keys($a)); array_shift($a); $a[] = 1; var_dump(array_keys($a));
Output for 4.3.2 - 7.2.0
array(1) { [0]=> int(0) } array(1) { [0]=> int(0) }
Output for 4.3.0 - 4.3.1
array(1) { [0]=> int(0) } array(1) { [0]=> int(1) }