• Stan Hu's avatar
    Fix slow Markdown rendering · be495c6a
    Stan Hu authored
    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
    be495c6a