The diff algorithm does not always keep HTML entity references intact, which can be problematic when later loading the resulting diff as HTML (e.g. when diffing a list entry). This is best illustrated by the following test:
<options></options>
<oldText>
<ol><li>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec non justo & sapien;</li></ol>
</oldText>
<newText>
<ol><li>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec non sapien et justo;</li></ol>
</newText>
<expected>
<ol class="diff-list"><li class="normal">Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec non <ins class="diffins">sapien et </ins>justo<del class="diffdel"> & sapien</del>;</li></ol>
</expected>This test currently crashes with an error message DOMDocument::loadHTML(): htmlParseEntityRef: expecting ';' in Entity, line: 1 from ListDiffLines.php:409. This is because it tries to load the string
<body>Lorem ipsum dolor sit amet, consectetur adipiscing elit. Donec non <ins class="diffins">sapien et </ins>justo<del class="diffdel"> &</del>;<del class="diffdel"> sapien;</del></body>
You can see that the diff algorithm broke up the & from its terminating ;, which leads to invalid HTML.
The solution might be to consider HTML entities a special case in the regex in AbstractDiff.php line 457 (e.g. adding an extra &[a-zA-Z0-9]+; case there). That fixes the given test without breaking the others, but I cannot oversee what further possible impact that may have.
The diff algorithm does not always keep HTML entity references intact, which can be problematic when later loading the resulting diff as HTML (e.g. when diffing a list entry). This is best illustrated by the following test:
This test currently crashes with an error message
DOMDocument::loadHTML(): htmlParseEntityRef: expecting ';' in Entity, line: 1fromListDiffLines.php:409. This is because it tries to load the stringYou can see that the diff algorithm broke up the
&from its terminating;, which leads to invalid HTML.The solution might be to consider HTML entities a special case in the regex in
AbstractDiff.phpline 457 (e.g. adding an extra&[a-zA-Z0-9]+;case there). That fixes the given test without breaking the others, but I cannot oversee what further possible impact that may have.