Re: RFC proposal: function array_filter_list() to avoid subtle bugs/workarounds

Hey Sergii, On Wed, 1 Feb 2023 at 18:22, Sergii Shymko <sergey@shymko.net> wrote: > Hi, > > After programming in PHP for two decades, my goal for 2023 is to try to > contribute to the language. > The plan is to start small and, if successful, work my way up increasing > complexity of proposals. > This topic has been chosen for starters, because IMO it strikes a good > balance between simplicity and usefulness. > I should be able to implement the RFC myself, unless some deep OPcache/JIT > nuances pop up. > > Let me give you a brief overview of the problem and the proposed solution.. > Function array_is_list() added in PHP 8.1 introduces the concept of a > "list" – array having 0..count-1 indexes. > The function is awesome and array "lists" are completely compatible with > all array_* functions! > However, function array_filter() exhibits a nuanced behavior when > filtering lists. > For instance, it preserves array keys which may (or may not) create gaps > in sequential indexes. > These gaps mean that a filtered list is not a list anymore as validated by > array_is_list(). > > For example: > $originalList = ['first', '', 'last']; > $filteredList = array_filter($originalList); > var_export(filteredList); // array(0 => 'first', 2 => 'last') > var_export(array_is_list($originalList)); // true > var_export(array_is_list($filteredList)); // false > > The behavior is counterintuitive and can lead to subtle bugs, such as > encoding issues: > echo json_encode($originalList); // ["first", "", "last"] > echo json_encode($filteredList); // {"0": "first", "2": > "last"} > > The workaround is to post-process the filtered array with array_values() > to reset the indexes. > The proposal is to introduce a function array_filter_list() that would > work solely on lists. > It will have the same signature as array_filter() and will always return a > valid list. > > See a draft RFC with more details here: > > N³eA>À > P(Mþhttps://dev.to/sshymko/php-rfc-arrayfilterlist-function-35mb-temp-slug-7074000?preview=21d6760126a02464b0511498bbb95749150afb17a7ff6377c458ee54a8f57cfe00d4e258aa06bad3232c0dd9e73a2d62138fc990048987e9e2339a3d > > I just registered a wiki account "sshymko" with the intention of > submitting the RFC. > Could someone please approve the account and give it some karma? > > Looking forward to collaborating with the internals team! 🙂 > > I don't want to shoot this down too early, but: 1. why in the language, when a simple userland function suffices? 2. what's wrong with writing array_values(array_filter(...))? Marco Pivetta https://twitter.com/Ocramius https://ocramius.github.io/