diff --git a/docs/differences/python_36.rst b/docs/differences/python_36.rst index 3315b0594dafc..7d294fbf6f136 100644 --- a/docs/differences/python_36.rst +++ b/docs/differences/python_36.rst @@ -25,7 +25,8 @@ Python 3.6 beta 1 was released on 12 Sep 2016, and a summary of the new features +--------------------------------------------------------+--------------------------------------------------+-----------------+ | `PEP 468 `_ | Preserving the order of *kwargs* in a function | | +--------------------------------------------------------+--------------------------------------------------+-----------------+ - | `PEP 487 `_ | Simpler customization of class creation | | + | `PEP 487 `_ | Simpler customization of class creation | Partial | + | | | [#setname]_ | +--------------------------------------------------------+--------------------------------------------------+-----------------+ | `PEP 520 `_ | Preserving Class Attribute Definition Order | | +--------------------------------------------------------+--------------------------------------------------+-----------------+ @@ -198,3 +199,7 @@ Changes to built-in modules: +--------------------------------------------------------------------------------------------------------------+----------------+ | The *compress()* and *decompress()* functions now accept keyword arguments | | +--------------------------------------------------------------------------------------------------------------+----------------+ + +.. rubric:: Notes + +.. [#setname] Only :func:`__set_name__` is implemented. diff --git a/py/mpconfig.h b/py/mpconfig.h index a1025fe5e1b18..787477358a06d 100644 --- a/py/mpconfig.h +++ b/py/mpconfig.h @@ -1124,7 +1124,7 @@ typedef time_t mp_timestamp_t; #define MICROPY_PY_FUNCTION_ATTRS_CODE (MICROPY_CONFIG_ROM_LEVEL_AT_LEAST_FULL_FEATURES) #endif -// Whether to support the descriptors __get__, __set__, __delete__ +// Whether to support the descriptors __get__, __set__, __delete__, __set_name__ // This costs some code size and makes load/store/delete of instance // attributes slower for the classes that use this feature #ifndef MICROPY_PY_DESCRIPTORS diff --git a/py/objtype.c b/py/objtype.c index b9af1008995ef..7455384541a49 100644 --- a/py/objtype.c +++ b/py/objtype.c @@ -661,8 +661,8 @@ static void mp_obj_instance_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *des // try __getattr__ if (attr != MP_QSTR___getattr__) { #if MICROPY_PY_DESCRIPTORS - // With descriptors enabled, don't delegate lookups of __get__/__set__/__delete__. - if (attr == MP_QSTR___get__ || attr == MP_QSTR___set__ || attr == MP_QSTR___delete__) { + // With descriptors enabled, don't delegate lookups of __get__/__set__/__delete__/__set_name__. + if (attr == MP_QSTR___get__ || attr == MP_QSTR___set__ || attr == MP_QSTR___delete__ || attr == MP_QSTR___set_name__) { return; } #endif @@ -960,7 +960,7 @@ static bool check_for_special_accessors(mp_obj_t key, mp_obj_t value) { #endif #if MICROPY_PY_DESCRIPTORS static const uint8_t to_check[] = { - MP_QSTR___get__, MP_QSTR___set__, MP_QSTR___delete__, + MP_QSTR___get__, MP_QSTR___set__, MP_QSTR___delete__, // not needed for MP_QSTR___set_name__ tho }; for (size_t i = 0; i < MP_ARRAY_SIZE(to_check); ++i) { mp_obj_t dest_temp[2]; @@ -974,6 +974,48 @@ static bool check_for_special_accessors(mp_obj_t key, mp_obj_t value) { } #endif +#if MICROPY_PY_DESCRIPTORS +// Shared data layout for the __set_name__ call and a linked list of calls to be made. +typedef union _setname_list_t setname_list_t; +union _setname_list_t { + mp_obj_t call[4]; + struct { + mp_obj_t _meth; + mp_obj_t _self; + setname_list_t *next; // can use the "owner" argument position temporarily for the linked list + mp_obj_t _name; + }; +}; + +// Append any `__set_name__` method on `value` to the setname list, with its per-attr args +static setname_list_t *setname_maybe_bind_append(setname_list_t *tail, mp_obj_t name, mp_obj_t value) { + // make certain our type-punning is safe: + MP_STATIC_ASSERT_NONCONSTEXPR(offsetof(setname_list_t, next) == offsetof(setname_list_t, call[2])); + + // tail is a blank list entry + mp_load_method_maybe(value, MP_QSTR___set_name__, tail->call); + if (tail->call[1] != MP_OBJ_NULL) { + // Each time a __set_name__ is found, leave it in-place in the former tail and allocate a new tail + tail->next = m_new_obj(setname_list_t); + tail->next->next = NULL; + tail->call[3] = name; + return tail->next; + } else { + return tail; + } +} + +// Execute the captured `__set_name__` calls, destroying the setname list in the process. +static inline void setname_consume_call_all(setname_list_t *head, mp_obj_t owner) { + setname_list_t *next; + while ((next = head->next) != NULL) { + head->call[2] = owner; + mp_call_method_n_kw(2, 0, head->call); + head = next; + } +} +#endif + static void type_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) { (void)kind; mp_obj_type_t *self = MP_OBJ_TO_PTR(self_in); @@ -1210,20 +1252,38 @@ mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict) } } + #if MICROPY_PY_DESCRIPTORS + // To avoid any dynamic allocations when no __set_name__ exists, + // the head of this list is kept on the stack (marked blank with `next = NULL`). + setname_list_t setname_list = { .next = NULL }; + setname_list_t *setname_tail = &setname_list; + #endif + #if ENABLE_SPECIAL_ACCESSORS - // Check if the class has any special accessor methods - if (!(o->flags & MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS)) { - for (size_t i = 0; i < locals_ptr->map.alloc; i++) { - if (mp_map_slot_is_filled(&locals_ptr->map, i)) { - const mp_map_elem_t *elem = &locals_ptr->map.table[i]; - if (check_for_special_accessors(elem->key, elem->value)) { - o->flags |= MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS; - break; - } + // Check if the class has any special accessor methods, + // and accumulate bound __set_name__ methods that need to be called + for (size_t i = 0; i < locals_ptr->map.alloc; i++) { + #if !MICROPY_PY_DESCRIPTORS + // __set_name__ needs to scan the entire locals map, can't early-terminate + if (o->flags & MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS) { + break; + } + #endif + + if (mp_map_slot_is_filled(&locals_ptr->map, i)) { + const mp_map_elem_t *elem = &locals_ptr->map.table[i]; + + if (!(o->flags & MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS) // elidable when the early-termination check is enabled + && check_for_special_accessors(elem->key, elem->value)) { + o->flags |= MP_TYPE_FLAG_HAS_SPECIAL_ACCESSORS; } + + #if MICROPY_PY_DESCRIPTORS + setname_tail = setname_maybe_bind_append(setname_tail, elem->key, elem->value); + #endif } } - #endif + #endif // ENABLE_SPECIAL_ACCESSORS const mp_obj_type_t *native_base; size_t num_native_bases = instance_count_native_bases(o, &native_base); @@ -1241,6 +1301,10 @@ mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict) } } + #if MICROPY_PY_DESCRIPTORS + setname_consume_call_all(&setname_list, MP_OBJ_FROM_PTR(o)); + #endif + return MP_OBJ_FROM_PTR(o); } diff --git a/tests/basics/class_descriptor.py b/tests/basics/class_descriptor.py index 83d31674301d5..feaed2fbb2a43 100644 --- a/tests/basics/class_descriptor.py +++ b/tests/basics/class_descriptor.py @@ -1,22 +1,28 @@ class Descriptor: def __get__(self, obj, cls): - print('get') + print("get") print(type(obj) is Main) print(cls is Main) - return 'result' + return "result" def __set__(self, obj, val): - print('set') + print("set") print(type(obj) is Main) print(val) def __delete__(self, obj): - print('delete') + print("delete") print(type(obj) is Main) + def __set_name__(self, owner, name): + print("set_name", name) + print(owner.__name__ == "Main") + + class Main: Forward = Descriptor() + m = Main() try: m.__class__ @@ -26,15 +32,15 @@ class Main: raise SystemExit r = m.Forward -if 'Descriptor' in repr(r.__class__): +if "Descriptor" in repr(r.__class__): # Target doesn't support descriptors. - print('SKIP') + print("SKIP") raise SystemExit # Test assignment and deletion. print(r) -m.Forward = 'a' +m.Forward = "a" del m.Forward # Test that lookup of descriptors like __get__ are not passed into __getattr__. diff --git a/tests/basics/class_setname_hazard.py b/tests/basics/class_setname_hazard.py new file mode 100644 index 0000000000000..dad4089a66610 --- /dev/null +++ b/tests/basics/class_setname_hazard.py @@ -0,0 +1,179 @@ +def skip_if_no_descriptors(): + class Descriptor: + def __get__(self, obj, cls): + return + + class TestClass: + Forward = Descriptor() + + a = TestClass() + try: + a.__class__ + except AttributeError: + # Target doesn't support __class__. + print("SKIP") + raise SystemExit + + b = a.Forward + if "Descriptor" in repr(b.__class__): + # Target doesn't support descriptors. + print("SKIP") + raise SystemExit + + +skip_if_no_descriptors() + + +# Test basic hazard-free mutations of the enclosing class. + + +class GetSibling: + def __set_name__(self, owner, name): + print(getattr(owner, name + "_sib")) + + +class GetSiblingTest: + desc = GetSibling() + desc_sib = 111 + + +t110 = GetSiblingTest() + + +class SetSibling: + def __set_name__(self, owner, name): + setattr(owner, name + "_sib", 121) + + +class SetSiblingTest: + desc = SetSibling() + + +t120 = SetSiblingTest() + +print(t120.desc_sib) + + +class DelSibling: + def __set_name__(self, owner, name): + delattr(owner, name + "_sib") + + +class DelSiblingTest: + desc = DelSibling() + desc_sib = 131 + + +t130 = DelSiblingTest() + +try: + print(t130.desc_sib) +except AttributeError: + print("AttributeError") + + +class GetSelf: + x = 211 + + def __set_name__(self, owner, name): + print(getattr(owner, name).x) + + +class GetSelfTest: + desc = GetSelf() + + +t210 = GetSelfTest() + + +class SetSelf: + def __set_name__(self, owner, name): + setattr(owner, name, 221) + + +class SetSelfTest: + desc = SetSelf() + + +t220 = SetSelfTest() + +print(t220.desc) + + +class DelSelf: + def __set_name__(self, owner, name): + delattr(owner, name) + + +class DelSelfTest: + desc = DelSelf() + + +t230 = DelSelfTest() + +try: + print(t230.desc) +except AttributeError: + print("AttributeError") + + +# Test exception behavior + + +class Raise: + def __set_name__(self, owner, name): + raise Exception() + + +try: + + class RaiseTest: + desc = Raise() +except Exception as e: + print("Exception") + + +# Test simple hazards: whether other class attributes still get __set_name__ even if removed before being run + + +class SetSpecific: + def __init__(self, sib_name, sib_replace): + self.sib_name = sib_name + self.sib_replace = sib_replace + + def __set_name__(self, owner, name): + setattr(owner, self.sib_name, self.sib_replace) + + +class SetReplaceTest: + a = SetSpecific("b", 312) # one of these is changed first + b = SetSpecific("a", 311) + + +t310 = SetReplaceTest() +print(t310.a) +print(t310.b) + + +class DelSpecific: + def __init__(self, sib_name): + self.sib_name = sib_name + + def __set_name__(self, owner, name): + delattr(owner, self.sib_name) + + +class DelReplaceTest: + a = DelSpecific("b") # one of these is removed first + b = DelSpecific("a") + + +t320 = DelReplaceTest() +try: + print(t320.a) +except AttributeError: + print("AttributeError") +try: + print(t320.b) +except AttributeError: + print("AttributeError") diff --git a/tests/basics/class_setname_hazard_rand.py b/tests/basics/class_setname_hazard_rand.py new file mode 100644 index 0000000000000..10270285dc5a4 --- /dev/null +++ b/tests/basics/class_setname_hazard_rand.py @@ -0,0 +1,130 @@ +# Test to make sure there's no sequence hazard even when a __set_name__ implementation +# mutates and reorders the class namespace. +# VERY hard bug to prove out except via a stochastic test. + + +def skip_if_no_descriptors(): + class Descriptor: + def __get__(self, obj, cls): + return + + class TestClass: + Forward = Descriptor() + + a = TestClass() + try: + a.__class__ + except AttributeError: + # Target doesn't support __class__. + print("SKIP") + raise SystemExit + + b = a.Forward + if "Descriptor" in repr(b.__class__): + # Target doesn't support descriptors. + print("SKIP") + raise SystemExit + + +def skip_if_no_libs(): + try: + import random + except ImportError: + # Target doesn't have a random library + print("SKIP") + raise SystemExit + + try: + random.choice + except AttributeError: + # Target doesn't have an ACTUAL random library + print("SKIP") + raise SystemExit + + try: + import re + except ImportError: + # Target doesn't have a regex library + print("SKIP") + raise SystemExit + + +skip_if_no_descriptors() +skip_if_no_libs() + + +import random +import re + +letters = "ABCDEFGHIJKLMNOPQRSTUVWXYZ" + +junk_re = re.compile(r"[A-Z][A-Z][A-Z][A-Z][A-Z]") + + +def junk_fill(obj, n=10): # Add randomly-generated attributes to an object. + for i in range(n): + name = "".join(random.choice(letters) for j in range(5)) + setattr(obj, name, object()) + + +def junk_clear(obj): # Remove attributes added by junk_fill. + to_del = [name for name in dir(obj) if junk_re.match(name)] + for name in to_del: + delattr(obj, name) + + +def junk_sequencer(): + global runs + try: + while True: + owner, name = yield + runs[name] = runs.get(name, 0) + 1 + junk_fill(owner) + finally: + junk_clear(owner) + + +class JunkMaker: + def __set_name__(self, owner, name): + global seq + seq.send((owner, name)) + + +runs = {} +seq = junk_sequencer() +next(seq) + + +class Main: + a = JunkMaker() + b = JunkMaker() + c = JunkMaker() + d = JunkMaker() + e = JunkMaker() + f = JunkMaker() + g = JunkMaker() + h = JunkMaker() + i = JunkMaker() + j = JunkMaker() + k = JunkMaker() + l = JunkMaker() + m = JunkMaker() + n = JunkMaker() + o = JunkMaker() + p = JunkMaker() + q = JunkMaker() + r = JunkMaker() + s = JunkMaker() + t = JunkMaker() + u = JunkMaker() + v = JunkMaker() + w = JunkMaker() + x = JunkMaker() + y = JunkMaker() + z = JunkMaker() + + +seq.close() + +for k in letters.lower(): + print(k, runs.get(k, 0)) pFad - Phonifier reborn

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