Implement DISALLOW_INSTANTIATION PyTypeFlags

stdlib/src/array.rs

@@ -1403,7 +1403,7 @@ mod array {
  internal: PyMutex<PositionIterInternal<PyArrayRef>>,
  }
 
- #[pyclass(with(IterNext, Iterable), flags(HAS_DICT))]
+ #[pyclass(with(IterNext, Iterable), flags(HAS_DICT, DISALLOW_INSTANTIATION))]
  impl PyArrayIter {
  #[pymethod(magic)]
  fn setstate(&self, state: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {

stdlib/src/csv.rs

@@ -921,7 +921,7 @@ mod _csv {
  }
  }
 
- #[pyclass(with(IterNext, Iterable))]
+ #[pyclass(with(IterNext, Iterable), flags(DISALLOW_INSTANTIATION))]
  impl Reader {
  #[pygetset]
  fn line_num(&self) -> u64 {
@@ -1075,7 +1075,7 @@ mod _csv {
  }
  }
 
- #[pyclass]
+ #[pyclass(flags(DISALLOW_INSTANTIATION))]
  impl Writer {
  #[pygetset(name = "dialect")]
  fn get_dialect(&self, _vm: &VirtualMachine) -> PyDialect {

stdlib/src/pystruct.rs

@@ -194,7 +194,7 @@ pub(crate) mod _struct {
  }
  }
 
- #[pyclass(with(IterNext, Iterable))]
+ #[pyclass(with(IterNext, Iterable), flags(DISALLOW_INSTANTIATION))]
  impl UnpackIterator {
  #[pymethod(magic)]
  fn length_hint(&self) -> usize {

stdlib/src/unicodedata.rs

@@ -97,7 +97,7 @@ mod unicodedata {
  }
  }
 
- #[pyclass]
+ #[pyclass(flags(DISALLOW_INSTANTIATION))]
  impl Ucd {
  #[pymethod]
  fn category(&self, character: PyStrRef, vm: &VirtualMachine) -> PyResult<String> {

stdlib/src/zlib.rs

@@ -293,7 +293,7 @@ mod zlib {
  unused_data: PyMutex<PyBytesRef>,
  unconsumed_tail: PyMutex<PyBytesRef>,
  }
- #[pyclass]
+ #[pyclass(flags(DISALLOW_INSTANTIATION))]
  impl PyDecompress {
  #[pygetset]
  fn eof(&self) -> bool {
@@ -468,7 +468,7 @@ mod zlib {
  inner: PyMutex<CompressInner>,
  }
 
- #[pyclass]
+ #[pyclass(flags(DISALLOW_INSTANTIATION))]
  impl PyCompress {
  #[pymethod]
  fn compress(&self, data: ArgBytesLike, vm: &VirtualMachine) -> PyResult<Vec<u8>> {

vm/src/builtins/type.rs

@@ -205,6 +205,7 @@ impl PyType {
  if base.slots.flags.has_feature(PyTypeFlags::HAS_DICT) {
  slots.flags |= PyTypeFlags::HAS_DICT
  }
+ let slots = Self::set_new(&base, slots);
 
  let new_type = PyRef::new_ref(
  PyType {
@@ -247,6 +248,7 @@ impl PyType {
 
  let bases = vec![base.clone()];
  let mro = base.iter_mro().map(|x| x.to_owned()).collect();
+ let slots = Self::set_new(&base, slots);
 
  let new_type = PyRef::new_ref(
  PyType {
@@ -397,6 +399,24 @@ impl PyType {
  }
  }
 
+ fn set_new(base: &PyRef<Self>, slots: PyTypeSlots) -> PyTypeSlots {
+ // TODO: must provide ctx to new_static
+ // if slots.new.load().is_none()
+ // && base.class().is(ctx.types.object_type)
+ // && slots.flags.contains(PyTypeFlags::HEAPTYPE)
+ // {
+ // slots.flags |= PyTypeFlags::DISALLOW_INSTANTIATION;
+ // }
+
+ if slots.flags.contains(PyTypeFlags::DISALLOW_INSTANTIATION) {
+ slots.new.store(None)
+ } else if slots.new.load().is_none() {
+ slots.new.store(base.slots.new.load())
+ }
+
+ slots
+ }
+
  pub fn slot_name(&self) -> BorrowedValue<str> {
  self.name_inner(
  |name| name.into(),
@@ -1094,13 +1114,23 @@ impl Callable for PyType {
  type Args = FuncArgs;
  fn call(zelf: &Py<Self>, args: FuncArgs, vm: &VirtualMachine) -> PyResult {
  vm_trace!("type_call: {:?}", zelf);
- let obj = call_slot_new(zelf.to_owned(), zelf.to_owned(), args.clone(), vm)?;
+ if zelf.is(vm.ctx.types.type_type) {
+ let num_args = args.args.len();
 
- if (zelf.is(vm.ctx.types.type_type) && args.kwargs.is_empty()) || !obj.fast_isinstance(zelf)
- {
- return Ok(obj);
+ if num_args == 1 && args.kwargs.is_empty() {
+ return Ok(args.args[0].obj_type());
+ }
+ if num_args != 3 {
+ return Err(vm.new_type_error("type() takes 1 or 3 arguments".to_owned()));
+ }
  }
 
+ let obj = if let Some(slot_new) = zelf.slots.new.load() {
+ slot_new(zelf.to_owned(), args.clone(), vm)?
+ } else {
+ return Err(vm.new_type_error(format!("cannot create '{}' instances", zelf.slots.name)));
+ };
+
  let init = obj.class().mro_find_map(|cls| cls.slots.init.load());
  if let Some(init_method) = init {
  init_method(obj.clone(), args, vm)?;

vm/src/types/slot.rs

@@ -122,6 +122,7 @@ bitflags! {
  #[derive(Copy, Clone, Debug, PartialEq)]
  #[non_exhaustive]
  pub struct PyTypeFlags: u64 {
+ const DISALLOW_INSTANTIATION = 1 << 7;
  const IMMUTABLETYPE = 1 << 8;
  const HEAPTYPE = 1 << 9;
  const BASETYPE = 1 << 10;