Ternary Associativity
The ternary operator used to have a left associativity : it would process first the then and else clauses, before executing itself.
Since PHP 8.0, the ternary operator produces a fatal error when the nested ternaries are ambiguous.
The update forces the code to use parenthesis, and set the priorities between the operators explicitly.
This doesn’t apply to the then clause, which is always unambiguous.
PHP code
<?php
$a = 2;
print $a == 1 ? 'one'
: $a == 2 ? 'two'
: $a == 3 ? 'three'
: 'other';
?>
Before
three
After
Fatal error: Unparenthesized `a ? b : c ? d : e` is not supported. Use either `(a ? b : c) ? d : e` or `a ? b : (c ? d : e)`
PHP version change
This behavior was deprecated in 7.4.
This behavior changed in 8.0.