The previous computation could result in invalid values, which could
lead to invalid promise ranges and subsequent crashes.

Don't include (part of) the PHP open tag in the HTML input.

JSP tags shouldn't trigger the PHP parser.  This used to happen and
trigger an infinite loop of a ping-pong effect with the HTML parser
asking the PHP parser to parse the JSP block, and the PHP parser, not
recognizing the input, asking the HTML one to deal with it.  Rinse and
repeat.