issue2551212 - enable wsgi cache_tracker by default Switch the code so the wsgi cache_tracker optimization is enabled by default. Leave the unoptimized/uncached code path available in case it breaks something. The feature flag can be set to False to disable caching. Updated tests to test the disabled (non-cache) code path. Updated upgrading.txt with info on how to disable caching.

try:
    from html import escape as html_escape_  # python 3

    def html_escape(string, quote=False):
        # html_escape under python 3 sets quote to true by default
        # make it python 2 compatible
        return html_escape_(string, quote=quote)
except ImportError:
    # python 2 fallback
    from cgi import escape as html_escape  # noqa: F401