From 091172f00ce0ba8ef2b495eed5e5aa07adc749da Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zandersgroup.com>
Date: Mon, 11 May 2026 13:23:49 +0200
Subject: [PATCH] Add macro for type check function in c-api

---
 crates/capi/src/object.rs | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/crates/capi/src/object.rs b/crates/capi/src/object.rs
index fb8fc3de54..3cfa461762 100644
--- a/crates/capi/src/object.rs
+++ b/crates/capi/src/object.rs
@@ -6,6 +6,35 @@ use rustpython_vm::{AsObject, Py};
 
 pub type PyTypeObject = Py<PyType>;
 
+macro_rules! define_py_check {
+    ($name:ident, $($ctx_path:ident).+) => {
+        #[unsafe(no_mangle)]
+        pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
+            crate::pystate::with_vm(|vm| unsafe {
+                obj
+                .as_ref()
+                .map(|obj| obj.class().is_subtype(vm.ctx.$($ctx_path).+))
+                .unwrap_or_default()
+            })
+        }
+    };
+    (exact $name:ident, $($ctx_path:ident).+) => {
+        #[unsafe(no_mangle)]
+        pub unsafe extern "C" fn $name(obj: *mut crate::PyObject) -> core::ffi::c_int {
+            use rustpython_vm::AsObject;
+            crate::pystate::with_vm(|vm| unsafe {
+                obj
+                .as_ref()
+                .map(|obj| obj.class().is(vm.ctx.$($ctx_path).+))
+                .unwrap_or_default()
+            })
+        }
+    };
+}
+
+define_py_check!(PyType_Check, types.type_type);
+define_py_check!(exact PyType_CheckExact, types.type_type);
+
 #[unsafe(no_mangle)]
 pub unsafe extern "C" fn Py_TYPE(op: *mut PyObject) -> *const PyTypeObject {
     unsafe { (*op).class() }
@@ -26,6 +55,15 @@ pub unsafe extern "C" fn PyType_GetFlags(ptr: *const PyTypeObject) -> c_ulong {
     ty.slots.flags.bits() as u32 as c_ulong
 }
 
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyType_IsSubtype(a: *const PyTypeObject, b: *const PyTypeObject) -> c_int {
+    with_vm(move |_vm| {
+        let a = unsafe { &*a };
+        let b = unsafe { &*b };
+        Ok(a.is_subtype(b))
+    })
+}
+
 #[unsafe(no_mangle)]
 pub extern "C" fn Py_GetConstantBorrowed(constant_id: c_uint) -> *mut PyObject {
     with_vm(|vm| {