Comparisons between strings and numbers using == and other non-strict comparison operators currently work by casting the string to a number and subsequently performing a comparison on integers or floats. This results in many surprising comparison results, the most notable of which is that 0 == "foobar" returns true. PHP 8 fixed this issue using number comparison when comparing to a numeric string. Otherwise, it converts the number to a string and uses a string comparison.
Comparison | Before | PHP 8 ------------------------------ 0 == "0" | true | true 0 == "0.0" | true | true 0 == "foo" | true | false 0 == "" | true | false 42 == " 42" | true | true 42 == "42foo" | true | false