Bug #80502 [Opn->Ver]: Comparison of empty string to 0

Edit report at https://bugs.php.net/bug.php?id=80502&edit=1 ID: 80502 Updated by: cmb@php.net Reported by: craig at craigfrancis dot co dot uk Summary: Comparison of empty string to 0 -Status: Open +Status: Verified Type: Bug Package: *General Issues Operating System: N/A PHP Version: 8.0.0 Block user comment: N Private report: N New Comment: Yes, that is indeed a consequence of that RFC. Since the empty string is not a well-formed numeric string, a string comparison is done, and the empty string is less than any other string. The migration guide should not only mention == comparision, but the other affected operations as well. And of course the respective documentation in the manual proper needs to be updated. Previous Comments: ------------------------------------------------------------------------ [2020-12-10 12:33:42] rtrtrtrtrt at dfdfdfdf dot dfd while i agree in the case of == which was always luck for < and > it's idiotic https://www.php.net/manual/de/migration80.incompatible.php Non-strict comparisons between numbers and non-numeric strings now work by casting the number to string and comparing the strings. Comparisons between numbers and numeric strings continue to work as before. Notably, this means that 0 == "not-a-number" is considered false now. Comparison Before After 0 == "0" TRUE TRUE 0 == "0.0" TRUE TRUE 0 == "foo" TRUE FALSE 0 == "" TRUE FALSE 42 == " 42" TRUE TRUE 42 == "42foo" TRUE FALSE ------------------------------------------------------------------------ [2020-12-10 12:27:28] craig at craigfrancis dot co dot uk And the same with ('' == 0)... PHP 7 this would be true, PHP 8 it's false. While I appreciate that's supposed to be false with ('' === 0), the double equals comparison operator is supposed to be equal "after type juggling". ------------------------------------------------------------------------ [2020-12-10 12:18:56] craig at craigfrancis dot co dot uk Description: ------------ Maybe related to RFC "string_to_number_comparison"? In PHP 7 the comparison ('' < 0) would convert the empty string to 0, then return false. But in PHP 8.0.0, the empty string is now considered less-than 0? Common issue for HTML forms, which provide all values as strings, and a blank number field is effectively seen as 0 - e.g. entering a time with separate fields (hours and minutes), and the user does not enter a value in the seconds field... yes, you could cast the value to an integer, but a lot of websites out there don't. Test script: --------------- var_export([ ('' < 0), ('1' < 0), ('0' < 0), ]); Expected result: ---------------- array ( 0 => false, 1 => false, 2 => false, ) Actual result: -------------- array ( 0 => true, 1 => false, 2 => false, ) ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=80502&edit=1