This is better for performance because these then don't need to be reevaluated every time they are called.
When encountering an unqualified function or constant reference, PHP will first try to locate a symbol in the current namespace by that name, and then fall back to the global namespace.
This short-circuits the check, which has substantial performance effects in some cases - in particular, ord(), chr() and strlen() show ~1500x faster calls when they are fully qualified.
However, this doesn't mean that PM is getting a massive amount faster. In real world terms, this translates to about 10-15% performance improvement.
But before anyone gets excited, you should know that the CodeOptimizer in the PreProcessor repo has been applying fully-qualified symbol optimizations to Jenkins builds for years, which is one of the reasons why Jenkins builds have better performance than home-built or source installations.
We're choosing to do this for the sake of future SafePHP integration and also to be able to get rid of the buggy CodeOptimizer, so that phar and source are more consistent.
https://bugs.php.net/bug.php?id=75992
When plugins do time-limited bans and users enter stupid time values, a shitty bug in ext/date gets triggered, but only when reading the ban entries from disk. DateTime->format() is able to produce formatted strings which have more than 4 digits in the year, which are then considered invalid. This works around it by trying to parse a formatted version on the fly to ensure that it is valid.
This also cleans up and improves ban list loading and handling.
