[Mlir-commits] [mlir] [mlir][python] value casting (PR #69644)

[Oleksandr Alex Zinenko]

================
@@ -1899,13 +1899,26 @@ bool PyTypeID::operator==(const PyTypeID &other) const {
 }
 
 //------------------------------------------------------------------------------
-// PyValue and subclases.
+// PyValue and subclasses.
 //------------------------------------------------------------------------------
 
 pybind11::object PyValue::getCapsule() {
   return py::reinterpret_steal<py::object>(mlirPythonValueToCapsule(get()));
 }
 
+pybind11::object PyValue::maybeDownCast() {
+  MlirType type = mlirValueGetType(get());
+  MlirTypeID mlirTypeID = mlirTypeGetTypeID(type);
+  assert(!mlirTypeIDIsNull(mlirTypeID) &&
+         "mlirTypeID was expected to be non-null.");
+  std::optional<pybind11::function> valueCaster =
+      PyGlobals::get().lookupValueCaster(mlirTypeID, mlirTypeGetDialect(type));
+  py::object thisObj = py::cast(this, py::return_value_policy::move);
----------------
ftynse wrote:

Nit: I'm often confused by various ownership/return value rules. What does `move` imply here?

https://github.com/llvm/llvm-project/pull/69644