Skip to content

Support inheriting from slots classes with gc=False #635

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jcrist merged 1 commit into from
Jan 21, 2024
Merged

Support inheriting from slots classes with gc=False #635

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 7 additions & 5 deletions msgspec/_core.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -5456,7 +5456,7 @@ typedef struct {
bool already_has_dict;
int cache_hash;
Py_ssize_t hash_offset;
bool has_non_struct_bases;
bool has_non_slots_bases;
} StructMetaInfo;

static int
Expand Down Expand Up @@ -5505,7 +5505,9 @@ structmeta_collect_base(StructMetaInfo *info, MsgspecState *mod, PyObject *base)
}

if (Py_TYPE(base) != &StructMetaType) {
info->has_non_struct_bases = true;
if (((PyTypeObject *)base)->tp_dictoffset) {
info->has_non_slots_bases = true;
}
/* XXX: in Python 3.8 Generic defines __new__, but we can ignore it.
* This can be removed when Python 3.8 support is dropped */
if (base == mod->typing_generic) return 0;
Expand Down Expand Up @@ -6221,7 +6223,7 @@ StructMeta_new_inner(
.already_has_dict = false,
.cache_hash = arg_cache_hash,
.hash_offset = 0,
.has_non_struct_bases = false,
.has_non_slots_bases = false,
};

info.defaults_lk = PyDict_New();
Expand Down Expand Up @@ -6273,10 +6275,10 @@ StructMeta_new_inner(
}

if (info.gc == OPT_FALSE) {
if (info.has_non_struct_bases) {
if (info.has_non_slots_bases) {
PyErr_SetString(
PyExc_ValueError,
"Cannot set gc=False when inheriting from non-struct types"
"Cannot set gc=False when inheriting from non-struct types with a __dict__"
);
goto cleanup;
}
Expand Down
18 changes: 14 additions & 4 deletions tests/test_struct.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1049,18 +1049,28 @@ class Test(Struct, gc=has_gc):
assert not gc.is_tracked(copy.copy(Test(1, ())))
assert gc.is_tracked(copy.copy(Test(1, []))) == has_gc

def test_struct_gc_false_forbids_mixins(self):
class Mixin:
def test_struct_gc_false_cannot_inherit_from_non_slots_classes(self):
class Base:
pass

with pytest.raises(
ValueError,
match="Cannot set gc=False when inheriting from non-struct types",
match="Cannot set gc=False when inheriting from non-struct types with a __dict__",
):

class Test(Struct, Mixin, gc=False):
class Test(Struct, Base, gc=False):
pass

def test_struct_gc_false_can_inherit_from_slots_class_mixin(self):
class Base:
__slots__ = ()

class Test(Struct, Base, gc=False):
x: int

t = Test(1)
assert not gc.is_tracked(t)

@pytest.mark.parametrize("case", ["base-dict", "base-nogc", "nobase"])
def test_struct_gc_false_forbids_dict_true(self, case):
if case == "base-dict":
Expand Down