Hi,
Since there is a discussion about the limited API and headers. A long time ago I asked about this on python-dev:
It concerns me a bit that the limited API does not seem to support MetaClasses in PyType_FromSpec (or FromSpecWithBase). In particular, last time I checked, it seemed impossible to extend the type struct within such a metaclass [1].
There also seemed to be an issue with PyType_FromSpecWithBases
allocating exactly a base type-object, instead of using tp_alloc as
PyType_Type.tp_new would.
This and how to efficiently cache Python objects in methods are the two main concerns I have right now for long-term full adoption of the limited API. (There are other difficulties, but for the ones I am aware, I at least have an idea how to they need to be addressed).
I suppose it may actually be possible to hack around the FromSpec issues, although I am not sure right now. unless subclassing PyType_Type in C is for some reason different and very much discouraged?
Cheers,
Sebastian
[1] And e.g. PySide seemed to "do" this, and got away with it, because there is an additional NULL at the end, as a termination for slots or so. Which for them is unused and they just happen to use.