diff options
| -rw-r--r-- | numpy/core/src/multiarray/usertypes.c | 67 |
1 files changed, 63 insertions, 4 deletions
diff --git a/numpy/core/src/multiarray/usertypes.c b/numpy/core/src/multiarray/usertypes.c index d0cf53576..a338d712d 100644 --- a/numpy/core/src/multiarray/usertypes.c +++ b/numpy/core/src/multiarray/usertypes.c @@ -268,6 +268,56 @@ PyArray_RegisterDataType(PyArray_Descr *descr) return typenum; } + +/* + * Checks that there is no cast already cached using the new casting-impl + * mechanism. + * In that case, we do not clear out the cache (but otherwise silently + * continue). Users should not modify casts after they have been used, + * but this may also happen accidentally during setup (and may never have + * mattered). See https://github.com/numpy/numpy/issues/20009 + */ +static int _warn_if_cast_exists_already( + PyArray_Descr *descr, int totype, char *funcname) +{ + PyArray_DTypeMeta *to_DType = PyArray_DTypeFromTypeNum(totype); + if (to_DType == NULL) { + return -1; + } + PyObject *cast_impl = PyDict_GetItemWithError( + NPY_DT_SLOTS(NPY_DTYPE(descr))->castingimpls, (PyObject *)to_DType); + Py_DECREF(to_DType); + if (cast_impl == NULL) { + if (PyErr_Occurred()) { + return -1; + } + } + else { + char *extra_msg; + if (cast_impl == Py_None) { + extra_msg = "the cast will continue to be considered impossible."; + } + else { + extra_msg = "the previous definition will continue to be used."; + } + Py_DECREF(cast_impl); + PyArray_Descr *to_descr = PyArray_DescrFromType(totype); + int ret = PyErr_WarnFormat(PyExc_RuntimeWarning, 1, + "A cast from %R to %R was registered/modified using `%s` " + "after the cast had been used. " + "This registration will have (mostly) no effect: %s\n" + "The most likely fix is to ensure that casts are the first " + "thing initialized after dtype registration. " + "Please contact the NumPy developers with any questions!", + descr, to_descr, funcname, extra_msg); + Py_DECREF(to_descr); + if (ret < 0) { + return -1; + } + } + return 0; +} + /*NUMPY_API Register Casting Function Replaces any function currently stored. @@ -279,14 +329,19 @@ PyArray_RegisterCastFunc(PyArray_Descr *descr, int totype, PyObject *cobj, *key; int ret; - if (totype < NPY_NTYPES_ABI_COMPATIBLE) { - descr->f->cast[totype] = castfunc; - return 0; - } if (totype >= NPY_NTYPES && !PyTypeNum_ISUSERDEF(totype)) { PyErr_SetString(PyExc_TypeError, "invalid type number."); return -1; } + if (_warn_if_cast_exists_already( + descr, totype, "PyArray_RegisterCastFunc") < 0) { + return -1; + } + + if (totype < NPY_NTYPES_ABI_COMPATIBLE) { + descr->f->cast[totype] = castfunc; + return 0; + } if (descr->f->castdict == NULL) { descr->f->castdict = PyDict_New(); if (descr->f->castdict == NULL) { @@ -328,6 +383,10 @@ PyArray_RegisterCanCast(PyArray_Descr *descr, int totype, "RegisterCanCast must be user-defined."); return -1; } + if (_warn_if_cast_exists_already( + descr, totype, "PyArray_RegisterCanCast") < 0) { + return -1; + } if (scalar == NPY_NOSCALAR) { /* |