[3.10] bpo-43760: Ensure that older Cython generated code compiles under 3.10.

[markshannon]

Not sure what sort of NEWS entry this needs, if any.

https://bugs.python.org/issue43760

[markshannon]

Why does the ABI checker claim this breaks the ABI?
The size of the PyThreadStatestruct is not part of the ABI. It is never passed by value, only be pointer.

[pablogsal]

The size of the PyThreadStatestruct is not part of the ABI. It is never passed by value, only be pointer.

Because code can dereference the pointer and if you know the full definition the compiler needs the offsets to optimize member access.

[pablogsal]

full definition the compiler needs the offsets to optimize member access.

For instance, this is this particular case:

 [C]'function void _PyErr_Clear(PyThreadState*)' at errors.c:453:1 has some indirect sub-type changes:
parameter 1 of type 'PyThreadState*' has sub-type changes:
in pointed to type 'typedef PyThreadState' at pystate.h:20:1:
underlying type 'struct _ts' at pystate.h:62:1 changed:
type size changed from 2240 to 2304 (in bits)
1 data member insertion:
'int _ts::use_tracing', at offset 384 (in bits) at pystate.h:79:1
6 data member changes (22 filtered):
'unsigned long int _ts::thread_id' offset changed from 1408 to 1472 (in bits) (by +64 bits)
'int _ts::trash_delete_nesting' offset changed from 1472 to 1536 (in bits) (by +64 bits)
'PyObject* _ts::trash_delete_later' offset changed from 1536 to 1600 (in bits) (by +64 bits)
'void (void*)* _ts::on_delete' offset changed from 1600 to 1664 (in bits) (by +64 bits)
'void* _ts::on_delete_data' offset changed from 1664 to 1728 (in bits) (by +64 bits)
'CFrame _ts::root_cframe' offset changed from 2112 to 2176 (in bits) (by +64 bits)

[pablogsal]

Don't worry too much, as the fields are not public we can just regenerate the ABI. The check is there so you don't change it unadvertedly.

[pablogsal]

Seems I cannot push to the fork you are using. Can you make sure the checkbox allowing pushes from maintaners is checked on this PR (on the right of the PR page, at the bottom IIRC)

[pablogsal]

[pablogsal]

Doesn't matter, I have created #28498