I think you may be missing the point, or maybe it's I who am missing the point. Your three very thorough examples are a good way of showing how (most?) languages handle floating-point arithmetic vs. arbitrary arithmetic.
But it seems to me - and let me stress that I am not a PHP developer and won't be bothered to install PHP on my machine at this time - that PHP is failing to exhibit exactly the behavior your code examples are giving.
Put it another way - type coercion 'run amok' being another thing entirely, you are correct that this bug stems from the fact that PHP is converting these integers to floating-point, and the standard floating point implementations will all behave in this exact way (thus, not a PHP bug.)
However, the issue here is that (again, "most?") languages also provide an easy way to get to arbitrary-precision arithmetic - and indeed, in the three examples you posted, you simply encode in the most natural way (by simply writing them) the two integers and they automatically compare correctly.
My understanding is that this is not the case in PHP, and that is a shame.
I agree that, when we are talking about high-level languages, I prefer ones that will transparently convert integers to bignum when required. I'm just replying to the contention that (paraphrased) "this is a bug in PHP's handling of floating point numbers".
But it seems to me - and let me stress that I am not a PHP developer and won't be bothered to install PHP on my machine at this time - that PHP is failing to exhibit exactly the behavior your code examples are giving.
Put it another way - type coercion 'run amok' being another thing entirely, you are correct that this bug stems from the fact that PHP is converting these integers to floating-point, and the standard floating point implementations will all behave in this exact way (thus, not a PHP bug.)
However, the issue here is that (again, "most?") languages also provide an easy way to get to arbitrary-precision arithmetic - and indeed, in the three examples you posted, you simply encode in the most natural way (by simply writing them) the two integers and they automatically compare correctly.
My understanding is that this is not the case in PHP, and that is a shame.