PHP RFC: Oniguruma maintenance end and end of mbregex

• Version: 0.1
• Date: 2025-08-21
• Author: Yuya Hamada youkidearitai@gmail.com
• Status: Under Discussion
• Implementation: https://github.com/php/php-src/pull/21490

Oniguruma maintenance ended on 2025-04-24. PHP uses mbregex (mb_ereg...) functions. So we decide future of mbregex. This proposal is ends of support mbregex PHP 9.0 and Deprecate 8.6.

Deprecate mbregex functions in PHP 8.6, Delete 9.0.

Deprecated: Function mb_ereg_replace() is deprecated since 8.6, Oniguruma functions support ends PHP 9.0 in %s on line %d

It is likely that the following points need to be decided, and how we will maintain versions 8.2 - 8.5.

• Maintenance versions: 8.2, 8.3, 8.4, 8.5
  • Mbregex instead of mb_onig
• Deprecate version: 8.6 (next after 8.5)
• Drop support: 9.0

Maintenance versions can use mbregex functions. However, FreeBSD will drop support on 2026-12-01 (ref: https://github.com/php/php-src/issues/18467#issuecomment-3044192511). We should decide what we will do after EOL in FreeBSD. (This is effect CI in php-src repository)

I suggest to below:

• External packaging for example https://github.com/youkidearitai/mb_onig/ (create by me)
• Disable mbregex in configure option(--disable-mbregex)

• mb_ereg
• mb_ereg_match
• mb_ereg_replace
• mb_ereg_replace_callback
• mb_ereg_search
• mb_ereg_search_getpos
• mb_ereg_search_getregs
• mb_ereg_search_init
• mb_ereg_search_pos
• mb_ereg_search_regs
• mb_ereg_search_setpos
• mb_eregi
• mb_eregi_replace
• mb_regex_encoding
• mb_regex_set_options
• mb_split

• MB_ONIGURUMA_VERSION

• mbstring.regex_retry_limit
• mbstring.regex_stack_limit

In Ruby, There is a Onigmo forked from Oniguruma.

However, Onigmo is different in Oniguruma.

• Performance(faster than Oniguruma)
• Unicode version
• Some expressions: `\K`, `\R`, `(?(cond)yes|no)`
  • Source: https://github.com/k-takata/Onigmo/blob/master/README

I quoted from https://news-web.php.net/php.internals/130429

Uses code from Juliette https://gist.github.com/jrfnl/bd0f66f1c185930427db4f093babf214

Summary of findings:

PHP CODE SNIFFER VIOLATION SOURCE SUMMARY
-------------------------------------------------------------------------------------------
SOURCE COUNT
-------------------------------------------------------------------------------------------
PHPCompatibility.FunctionUse.RemovedFunctions.mb_splitDeprecated 30
PHPCompatibility.FunctionUse.RemovedFunctions.mb_regex_encodingDeprecated 25
PHPCompatibility.FunctionUse.RemovedFunctions.mb_eregi_replaceDeprecated 20
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_replaceDeprecated 18
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_matchDeprecated 13
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_search_initDeprecated 10
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_search_regsDeprecated 9
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_replace_callbackDeprecated 6
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_search_getregsDeprecated 5
PHPCompatibility.FunctionUse.RemovedFunctions.mb_eregDeprecated 4
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_search_setposDeprecated 4
PHPCompatibility.FunctionUse.RemovedFunctions.mb_eregiDeprecated 2
PHPCompatibility.FunctionUse.RemovedFunctions.mb_ereg_search_posDeprecated 1
-------------------------------------------------------------------------------------------
A TOTAL OF 147 SNIFF VIOLATIONS WERE FOUND IN 13 SOURCES
-------------------------------------------------------------------------------------------

Thanks, Juliette.

However, Probably proprietary software are uses mbregex functions. Impact is larger than that result.

This RFC is big impact from multibyte(not UTF-8) users.

Therefore, I created bailout extension mb_onig https://packagist.org/packages/mb_onig/mb_onig that we can still use mbregex functions. So PHP 8.x can still use mbregex functions and we can still maintain mbregex for PHP 9.x.

Debian/Ubuntu users calls Oniguruma to `onig`. I quoted this.

$ sudo apt search onig
libonig-dev/noble,now 6.9.9-1build1 amd64 [installed]
  regular expressions library — development files

libonig5/noble,now 6.9.9-1build1 amd64 [installed,automatic]
  regular expressions library

./configure --enable-mbstring --disable-mbregex
make
make install
pie install mb_onig/mb_onig

./configure --enable-mbstring
make
make install
pie install mb_onig/mb_onig

The mbregex functions cannot be used.

Deprecate for 8.6 and remove in 9.0.

Mbregex

Describe the impact to CLI, Development web server, embedded PHP etc.

https://github.com/php/php-src/issues/18467

This section should outline areas that you are not planning to work on in the scope of this RFC, but that might be iterated upon in the future by yourself or another contributor.

This helps with long-term planning and ensuring this RFC does not prevent future work.

• Drop support the mbregex functions, Deprecate 8.6 and delete 9.0

• Re-include Oniguruma version: https://github.com/php/php-src/pull/19258
• mb_onig: https://github.com/youkidearitai/mb_onig
  • Packagist: https://packagist.org/packages/mb_onig/mb_onig
• Deprecate mbregex: https://github.com/php/php-src/pull/21490

• Mailing list when mbregex was changed to Oniguruma (Japanese mailing list ml.php.gr.jp)
• https://externals.io/message/127245#127245

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

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.