Investigate spec compliance (PHP 84)

[veewee]

Feature Request

More info:

• https://externals.io/message/122363
• RFC : https://wiki.php.net/rfc/opt_in_dom_spec_compliance
• RFC : HTML5 separation : https://wiki.php.net/rfc/domdocument_html5_parser

WIP: Extended DOM

• Extra dom additions 1 nielsdos/php-src#93

Additional new PHP 84 RFCs:

• RFC : https://wiki.php.net/rfc/improve_callbacks_dom_and_xsl
• RFC : https://wiki.php.net/rfc/xmlreader_writer_streams

Branch php/php-src#13031

./buildconf --force
make clean
./configure --without-iconv --enable-mbstring --disable-opcache --with-xsl
make -j4
./sapi/cli/php -v

Investigation

General idea : create v4 (or higher) that requries PHP 8.4 and make the DOM layer spec compliant.
Downside : this drops support for all older PHP versions which will be annoying.
Both v3 and v4 could remain LTS branches that are compatible in functionality.
However, this would be a maintainence pain for at least for the coming 3-4 year.
It won't be possible to support both v3 and v4 in downstream repo's either, since the signatures of the callbacks will be different.

First steps

•  POC : Try to get current DOM layer working with the new spec-compliant version.