From 2ae701e82539ee346c3721e5ed9d7b8b6c69e08c Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <7943856+bschoenmaeckers@users.noreply.github.com>
Date: Wed, 21 Oct 2026 05:02:11 +0200
Subject: [PATCH] Add a test for `PyType_FromSpec` (#9258)

---
 crates/capi/src/object/pytype.rs | 32 +++++++++++++++++++++++++++++++-
 crates/capi/src/slots.rs         |  2 ++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/crates/capi/src/object/pytype.rs b/crates/capi/src/object/pytype.rs
index 44d3ff2f2..8d05ef0bf 100644
--- a/crates/capi/src/object/pytype.rs
+++ b/crates/capi/src/object/pytype.rs
@@ -128,7 +128,9 @@ pub unsafe extern "C" fn PyType_FromSlots(slots: *const PySlot) -> *mut PyObject
                             })?;
                             type_slots.flags = AtomicPyTypeFlags::from_plain(flags);
                         }
-                        PySlotType::BasicSize(size) | PySlotType::ExtraBasicSize(size) => {
+                        PySlotType::BasicSize(size)
+                        | PySlotType::ExtraBasicSize(size)
+                        | PySlotType::ItemSize(size) => {
                             if size != 0 {
                                 return Err(vm.new_not_implemented_error(
                                     "PyType_FromSlots with non-zero size is not yet supported",
@@ -323,6 +325,7 @@ pub extern "C" fn PyType_Freeze(_ty: *mut PyTypeObject) -> c_int {
 #[cfg(test)]
 mod tests {
     use pyo3::IntoPyObjectExt;
+    use pyo3::ffi;
     use pyo3::prelude::*;
     use pyo3::types::{PyDict, PyInt, PyList, PyString, PyType, PyTypeMethods};
 
@@ -512,4 +515,31 @@ mod tests {
             );
         });
     }
+
+    #[test]
+    fn type_from_spec() {
+        Python::attach(|py| {
+            let mut slots = [ffi::PyType_Slot {
+                slot: 0,
+                pfunc: core::ptr::null_mut(),
+            }];
+            let mut spec = ffi::PyType_Spec {
+                name: c"somemodule.MySpecClass".as_ptr(),
+                basicsize: 0,
+                itemsize: 0,
+                flags: ffi::Py_TPFLAGS_DEFAULT as _,
+                slots: slots.as_mut_ptr(),
+            };
+
+            let type_ptr = unsafe { ffi::PyType_FromSpec(&mut spec) };
+            let type_obj = unsafe {
+                Bound::from_borrowed_ptr_or_err(py, type_ptr)
+                    .unwrap()
+                    .cast_into::<PyType>()
+                    .unwrap()
+            };
+
+            assert_eq!(type_obj.qualname().unwrap(), "somemodule.MySpecClass");
+        });
+    }
 }
diff --git a/crates/capi/src/slots.rs b/crates/capi/src/slots.rs
index 7e6ed3899..590ffcf3b 100644
--- a/crates/capi/src/slots.rs
+++ b/crates/capi/src/slots.rs
@@ -158,6 +158,7 @@ impl PySlot {
             })),
             96 => PySlotKind::Type(PySlotType::BasicSize(unsafe { self.value.sl_size })),
             97 => PySlotKind::Type(PySlotType::ExtraBasicSize(unsafe { self.value.sl_size })),
+            98 => PySlotKind::Type(PySlotType::ItemSize(unsafe { self.value.sl_size })),
             99 => PySlotKind::Type(PySlotType::Flags(unsafe { self.value.sl_uint64 })),
             100 => PySlotKind::Module(PySlotModule::Name(unsafe {
                 value_ptr.cast::<c_char>().try_as_str(vm)?
@@ -239,6 +240,7 @@ pub(crate) enum PySlotType<'a> {
     Flags(u64),
     BasicSize(isize),
     ExtraBasicSize(isize),
+    ItemSize(isize),
     Metaclass(&'a Py<PyType>),
     Module(&'a Py<PyModule>),
 }