Fix slow Markdown rendering
The sanitize transformers were being duplicated each time the Markdown renderer was called, leading to expontential growth in rendering times.
The problem was that although HTML::Pipeline::SanitizationFilter.WHITELIST
is a frozen hash, the :transformers
array can be modified. We need
to do deep copy of this to avoid adding duplicates.
Closes #49409 (closed)
Edited by Stan Hu