PHP: rfc:grapheme_limit_codepoints

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
====== PHP RFC: Your Title Here ======
  * Version: 0.9
  * Date: 2026-02-28
  * Author: Yuya Hamada <youkidearitai@gmail.com>
  * Status: Draft
  * Implementation: https://github.com/php/php-src/pull/21311

I noticed there is not exist limit of codepoint that reading Unicode Standard Annex #29([[https://www.unicode.org/reports/tr29/|UAX#29]]). So that means grapheme cluster can crash computer because computer resource is limited but grapheme cluster is not limited.



===== Introduction =====
This proposal is use to safe for grapheme cluster that it is limit codepoint.

<PHP>
<?php
$f = "あい👨‍👨‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦‍👦うえお";
var_dump(grapheme_limit_codepoints($f)); // returns false because no 3 grapheme cluster is greater than 32 codepoints.

$f = "あいうえお👨‍👨‍👦";
var_dump(grapheme_limit_codepoints($f)); // returns true

$f = "あいうえおH̵̛͕̞̦̰̜͍̰̥̟͆̏͂̌͑ͅä̷͔̟͓̬̯̟͍̭͉͈̮͙̣̯̬͚̞̭̍̀̾͠m̴̡̧̛̝̯̹̗̹̤̲̺̟̥̈̏͊̔̑̍͆̌̀̚͝͝b̴̢̢̫̝̠̗̼̬̻̮̺̭͔̘͑̆̎̚ư̵̧̡̥̙̭̿̈̀̒̐̊͒͑r̷̡̡̲̼̖͎̫̮̜͇̬͌͘g̷̹͍͎̬͕͓͕̐̃̈́̓̆̚͝ẻ̵̡̼̬̥̹͇̭͔̯̉͛̈́̕r̸̮̖̻̮̣̗͚͖̝̂͌̾̓̀̿̔̀͋̈́͌̈́̋͜👨‍👨‍👦";
var_dump(grapheme_limit_codepoints($f)); // returns true because zalgo text for Hamburger but lower than 32 codepoints
?>
</PHP>

===== Proposal =====
Check grapheme cluster's codepoints lower than $limit

<PHP>
<?php
function grapheme_limit_codepoints(string $string, int $limit = GRAPHEME_LIMIT_CODEPOINTS): bool {}
?>
</PHP>

GRAPHEME_LIMIT_CODEPOINTS is 32, Because based on [[https://unicode.org/reports/tr15/#UAX15-D3|UAX#15 Stream-safe Text Format]]. Unicode's official answer is not rely Stream-safe Text Format, But I think make sense to it.

==== Examples ====
Check the codepoints per grapheme cluster. Then measure grapheme_strlen.

Simple example:
<PHP>
<?php

$f = "あいうえお👨‍👨‍👦";
var_dump(grapheme_limit_codepoints($f)); // true
var_dump(grapheme_strlen($f)); // result is 6

?>
</PHP>


===== Backward Incompatible Changes =====


This could break a function existing in userland with the same name.


===== Proposed PHP Version(s) =====
Next of PHP 8.5 (PHP 8.6 or PHP 9.0)

===== RFC Impact =====
==== To the Ecosystem ====
None

==== To Existing Extensions ====
Adds grapheme_limit_codepoints() to the intl extension.


==== To SAPIs ====
None

===== Future Scope =====
None

===== Voting Choices =====

Please consult [[https://github.com/php/policies/blob/main/feature-proposals.rst#voting-phase|the php/policies repository]] for the current voting guidelines.

----

Primary Vote requiring a 2/3 majority to accept the RFC:

<doodle title="Add grapheme_limit_codepoints" voteType="single" closed="false" closeon="2026-01-01T15:30:00Z">
   * Yes
   * No
   * Abstain
</doodle>

===== Patches and Tests =====
https://github.com/php/php-src/pull/21311

===== Implementation =====


===== References =====
  * https://www.unicode.org/reports/tr29/
  * https://unicode-org.atlassian.net/browse/ICU-23302

===== Rejected Features =====
Keep this updated with features that were discussed on the mail lists.

===== Changelog =====
If there are major changes to the initial proposal, please include a short summary with a date or a link to the mailing list announcement here, as not everyone has access to the wikis' version history.
Page Tools
