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.
This filters out over 200 invalid states which were previously considered just fine, including zero-width cakes, buttons with broken facing values, furnace/chest with crazy values, and more.
This will be needed to deal with things like chest/furnace which don't use 0 as a valid state (these both use facing horizontal for rotation, and vertical is invalid, so 0 would mean downwards facing which is invalid.
This is a major change to the way block metadata is handled within the PM core. This separates variant metadata (which really ought to be part of the ID) from state metadata, and in a couple of cases flattens separate states of blocks together.
The result of this is that invalid variants can be much more easily detected, and additionally state handling is much cleaner since meta is only needed at the serialize layer instead of throughout the code.
This is basically how blockstate discovery would actually work in the full-blown system. This maps blocks with unrecognized blockstates to static runtimeIDs not known to the client.
This means that all blocks which don't have corresponding runtimeIDs in the new system will translate to update! blocks instead.
Mojang do this differently: they try to a) match id+meta, if that fails b) match id+0, and if that fails, then replace with update! block runtime ID. I can't do that here because I need to be able to convert both ways. They only need to be able to convert from legacy -> new.
These are never called accidentally, or at least it's highly unlikely to do so. It might be reasonable to throw exceptions for this, but for the meantime they are redundant - extra indentation for no good reason.
This also removes the $force parameter from BlockFactory::init().
