Hi, On 22/03/2022 6:07 pm, Victor Stinner wrote:
Hi,
I proposed two PRs to move the private C API (Include/cpython/) of PEP 523 "Adding a frame evaluation API to CPython" to the internal C API (Include/internals/):
* https://github.com/python/cpython/pull/32052 * https://github.com/python/cpython/pull/32054
I just want to say that it is important the API is easy to use and access. Otherwise there is a temptation to directly set the underlying function pointer, and that means we don't get to see when PEP 523 is used. We might then mis-optimize on the assumption that PEP 523 isn't used. Cheers, Mark.
API:
* _PyFrameEvalFunction type * _PyInterpreterState_GetEvalFrameFunc() * _PyInterpreterState_SetEvalFrameFunc() * (undocumented) _PyEval_EvalFrameDefault()
The private API to get/set the eval function *is* documented at: https://docs.python.org/dev/c-api/init.html#c._PyInterpreterState_GetEvalFra...
I added the Get/Set functions so debuggers don't have to access directly to the PyInterpreterState structure which has been moved to the internal C API in Python 3.8.
This API causes me multiple issues:
* It's a private API and I'm trying to remove the private API from the public C API header files. * The _PyFrameEvalFunction type is not stable: it got a new "tstate" parameter in Python 3.9 and the type of the second parameter changed from PyFrameObject* to _PyInterpreterFrame* in Python 3.11. * These functions use the _PyInterpreterFrame type which is part of the internal C API.
While Pyston didn't bring a JIT compiler to Python with PEP 523, debuggers were made faster by using this API. Debuggers like pydevd, debugpy and ptvsd use it.
I propose to move theses API to the internal header files (Include/internals/) to clarify that it's not part of the public C API and that there is no backward compatibility warranty.
The change is being discussed at: https://bugs.python.org/issue46850
--
PEP 523 API added more private functions for code objects:
* _PyEval_RequestCodeExtraIndex() * _PyCode_GetExtra() * _PyCode_SetExtra()
The _PyEval_RequestCodeExtraIndex() function seems to be used by the pydevd debugger. The two others seem to be unused in the wild. I'm not sure if these ones should be moved to the internal C API. They can be left unchanged, since they don't use a type only defined by the internal C API.
Victor