Don't let PyInstanceMethod hide itself

Python 3's `PyInstanceMethod_Type` hides itself via its `tp_descr_get`,
which prevents aliasing methods via `cls.attr("m2") = cls.attr("m1")`:
instead the `tp_descr_get` returns a plain function, when called on a
class, or a `PyMethod`, when called on an instance.  Override that
behaviour for pybind11 types with a special bypass for
`PyInstanceMethod_Types`.
This commit is contained in:
Jason Rhinelander
2017-04-16 20:30:52 -04:00
parent a7f704b39b
commit 0a90b2db71
5 changed files with 50 additions and 6 deletions

View File

@@ -149,6 +149,24 @@ extern "C" inline int pybind11_meta_setattro(PyObject* obj, PyObject* name, PyOb
}
}
#if PY_MAJOR_VERSION >= 3
/** Python 3's PyInstanceMethod_Type hides itself via its tp_descr_get, which prevents aliasing
* methods via cls.attr("m2") = cls.attr("m1"): instead the tp_descr_get returns a plain function,
* when called on a class, or a PyMethod, when called on an instance. Override that behaviour here
* to do a special case bypass for PyInstanceMethod_Types.
*/
extern "C" inline PyObject *pybind11_meta_getattro(PyObject *obj, PyObject *name) {
PyObject *descr = _PyType_Lookup((PyTypeObject *) obj, name);
if (descr && PyInstanceMethod_Check(descr)) {
Py_INCREF(descr);
return descr;
}
else {
return PyType_Type.tp_getattro(obj, name);
}
}
#endif
/** This metaclass is assigned by default to all pybind11 types and is required in order
for static properties to function correctly. Users may override this using `py::metaclass`.
Return value: New reference. */
@@ -176,6 +194,9 @@ inline PyTypeObject* make_default_metaclass() {
type->tp_new = pybind11_meta_new;
type->tp_setattro = pybind11_meta_setattro;
#if PY_MAJOR_VERSION >= 3
type->tp_getattro = pybind11_meta_getattro;
#endif
if (PyType_Ready(type) < 0)
pybind11_fail("make_default_metaclass(): failure in PyType_Ready()!");

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@@ -135,6 +135,8 @@
#if PY_MAJOR_VERSION >= 3 /// Compatibility macros for various Python versions
#define PYBIND11_INSTANCE_METHOD_NEW(ptr, class_) PyInstanceMethod_New(ptr)
#define PYBIND11_INSTANCE_METHOD_CHECK PyInstanceMethod_Check
#define PYBIND11_INSTANCE_METHOD_GET_FUNCTION PyInstanceMethod_GET_FUNCTION
#define PYBIND11_BYTES_CHECK PyBytes_Check
#define PYBIND11_BYTES_FROM_STRING PyBytes_FromString
#define PYBIND11_BYTES_FROM_STRING_AND_SIZE PyBytes_FromStringAndSize
@@ -153,6 +155,8 @@
extern "C" PYBIND11_EXPORT PyObject *PyInit_##name()
#else
#define PYBIND11_INSTANCE_METHOD_NEW(ptr, class_) PyMethod_New(ptr, nullptr, class_)
#define PYBIND11_INSTANCE_METHOD_CHECK PyMethod_Check
#define PYBIND11_INSTANCE_METHOD_GET_FUNCTION PyMethod_GET_FUNCTION
#define PYBIND11_BYTES_CHECK PyString_Check
#define PYBIND11_BYTES_FROM_STRING PyString_FromString
#define PYBIND11_BYTES_FROM_STRING_AND_SIZE PyString_FromStringAndSize

View File

@@ -268,10 +268,8 @@ protected:
rec->is_constructor = !strcmp(rec->name, "__init__") || !strcmp(rec->name, "__setstate__");
rec->nargs = (std::uint16_t) args;
#if PY_MAJOR_VERSION < 3
if (rec->sibling && PyMethod_Check(rec->sibling.ptr()))
rec->sibling = PyMethod_GET_FUNCTION(rec->sibling.ptr());
#endif
if (rec->sibling && PYBIND11_INSTANCE_METHOD_CHECK(rec->sibling.ptr()))
rec->sibling = PYBIND11_INSTANCE_METHOD_GET_FUNCTION(rec->sibling.ptr());
detail::function_record *chain = nullptr, *chain_start = rec;
if (rec->sibling) {