diff --git a/Include/cpython/object.h b/Include/cpython/object.h index a65aaf6482159c..5a0ac4afdae83d 100644 --- a/Include/cpython/object.h +++ b/Include/cpython/object.h @@ -256,6 +256,9 @@ typedef struct _typeobject { destructor tp_finalize; vectorcallfunc tp_vectorcall; + /* bpo-37250: kept for backwards compatibility in CPython 3.8 only */ + Py_DEPRECATED(3.8) int (*tp_print)(PyObject *, FILE *, int); + #ifdef COUNT_ALLOCS /* these must be last and never explicitly initialized */ Py_ssize_t tp_allocs; diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py index 49f2722d95140e..a7df7a2fc8c978 100644 --- a/Lib/test/test_sys.py +++ b/Lib/test/test_sys.py @@ -1275,7 +1275,7 @@ def delx(self): del self.__x check((1,2,3), vsize('') + 3*self.P) # type # static type: PyTypeObject - fmt = 'P2nPI13Pl4Pn9Pn11PIPP' + fmt = 'P2nPI13Pl4Pn9Pn11PIPPP' if hasattr(sys, 'getcounts'): fmt += '3n2P' s = vsize(fmt) diff --git a/Misc/NEWS.d/next/C API/2019-06-12-11-45-36.bpo-37221.RhP1E7.rst b/Misc/NEWS.d/next/C API/2019-06-12-11-45-36.bpo-37221.RhP1E7.rst new file mode 100644 index 00000000000000..96b61dea0d9cde --- /dev/null +++ b/Misc/NEWS.d/next/C API/2019-06-12-11-45-36.bpo-37221.RhP1E7.rst @@ -0,0 +1,4 @@ +``tp_print`` is put back at the end of the ``PyTypeObject`` structure +to restore support for old code (in particular generated by Cython) +setting ``tp_print = 0``. +Note that ``tp_print`` will be removed entirely in Python 3.9. diff --git a/Modules/_testcapimodule.c b/Modules/_testcapimodule.c index 07aadea3e98395..1042ea701923c2 100644 --- a/Modules/_testcapimodule.c +++ b/Modules/_testcapimodule.c @@ -6008,6 +6008,10 @@ PyInit__testcapi(void) Py_INCREF(&MyList_Type); PyModule_AddObject(m, "MyList", (PyObject *)&MyList_Type); + /* bpo-37250: old Cython code sets tp_print to 0, we check that + * this doesn't break anything. */ + MyList_Type.tp_print = 0; + if (PyType_Ready(&MethodDescriptorBase_Type) < 0) return NULL; Py_INCREF(&MethodDescriptorBase_Type);