A fix was introduced to the Tag Processor to ensure that contiguous text
in an HTML document emerges as a single text node spanning the full
sequence. Unfortunately, that patch was marginally over-zealous in
checking if a "<" started a syntax token or not. It used the following:
{{{
<?php
if ( 'A' <= $c && 'z' >= $c ) { ... }
}}}
This was based on the assumption that the A-Z and a-z letters are
contiguous in the ASCII range; they aren't, and there's a gap of
several characters in between. The result of this is that in some
cases the parser created a text boundary when it didn't need to.
Text boundaries can be surprising and can be created when reaching
invalid syntax, HTML comments, and more hidden elements, so
semantically this wasn't a major bug, but it was an aesthetic
challenge.
In this patch the check is properly compared for both upper- and
lower-case variants that could potentially form tag names.
{{{
<?php
if ( ( 'A' <= $c && 'Z' >= $c ) || ( 'a' <= $c && 'z' >= $c ) ) { ... }
}}}
This solves the problem and ensures that contiguous text appears
as a single text node when scanning tokens.
Developed in https://github.com/WordPress/wordpress-develop/pull/6041
Discussed in https://core.trac.wordpress.org/ticket/60385
Follow-up to [57489]
Props dmsnell, jonsurrell
Fixes#60385
Built from https://develop.svn.wordpress.org/trunk@57542
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