Fix a memory leak when using PyList_SET_ITEM on GraalPy

Author: timfel

newsfragments/1.fixed.md

@@ -0,0 +1 @@
+Fix memory leak using `PyList_SET_ITEM` on GraalPy

pyo3-ffi/src/cpython/listobject.rs

@@ -28,9 +28,18 @@ pub unsafe fn PyList_GET_ITEM(op: *mut PyObject, i: Py_ssize_t) -> *mut PyObject
 
 /// Macro, *only* to be used to fill in brand new lists
 #[inline]
-#[cfg(not(any(PyPy, GraalPy)))]
+#[cfg(not(PyPy))]
 pub unsafe fn PyList_SET_ITEM(op: *mut PyObject, i: Py_ssize_t, v: *mut PyObject) {
-    *(*(op as *mut PyListObject)).ob_item.offset(i) = v;
+    #[cfg(not(GraalPy))]
+    {
+        *(*(op as *mut PyListObject)).ob_item.offset(i) = v;
+    }
+    #[cfg(GraalPy)]
+    {
+        let previous = crate::PyList_GetItem(op, i);
+        Py_XDECREF(previous);
+        crate::PyList_SetItem(op, i, v);
+    }
 }
 
 #[inline]

pyo3-ffi/src/listobject.rs

@@ -69,8 +69,7 @@ extern "C" {
     #[cfg(PyPy)]
     #[cfg_attr(PyPy, link_name = "PyPyList_GET_SIZE")]
     pub fn PyList_GET_SIZE(arg1: *mut PyObject) -> Py_ssize_t;
-    #[cfg(any(PyPy, GraalPy))]
+    #[cfg(PyPy)]
     #[cfg_attr(PyPy, link_name = "PyPyList_SET_ITEM")]
-    #[cfg_attr(GraalPy, link_name = "_PyList_SET_ITEM")]
     pub fn PyList_SET_ITEM(arg1: *mut PyObject, arg2: Py_ssize_t, arg3: *mut PyObject);
 }