Fix indirect loading of Eigen::Ref
Put the caster's temporary array on life support to ensure correct
lifetime when it's being used as a subcaster.
diff --git a/tests/test_eigen.cpp b/tests/test_eigen.cpp
index 52358ab..413fed3 100644
--- a/tests/test_eigen.cpp
+++ b/tests/test_eigen.cpp
@@ -10,6 +10,7 @@
#include "pybind11_tests.h"
#include "constructor_stats.h"
#include <pybind11/eigen.h>
+#include <pybind11/stl.h>
#include <Eigen/Cholesky>
using MatrixXdR = Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>;
@@ -298,4 +299,17 @@
.def(py::init<>())
.def_readonly("a", &CustomOperatorNew::a)
.def_readonly("b", &CustomOperatorNew::b);
+
+ // test_eigen_ref_life_support
+ // In case of a failure (the caster's temp array does not live long enough), creating
+ // a new array (np.ones(10)) increases the chances that the temp array will be garbage
+ // collected and/or that its memory will be overridden with different values.
+ m.def("get_elem_direct", [](Eigen::Ref<const Eigen::VectorXd> v) {
+ py::module::import("numpy").attr("ones")(10);
+ return v(5);
+ });
+ m.def("get_elem_indirect", [](std::vector<Eigen::Ref<const Eigen::VectorXd>> v) {
+ py::module::import("numpy").attr("ones")(10);
+ return v[0](5);
+ });
});
diff --git a/tests/test_eigen.py b/tests/test_eigen.py
index f9ad3a5..c9fe69f 100644
--- a/tests/test_eigen.py
+++ b/tests/test_eigen.py
@@ -602,6 +602,21 @@
', flags.c_contiguous' in str(excinfo.value))
+def test_eigen_ref_life_support():
+ """Ensure the lifetime of temporary arrays created by the `Ref` caster
+
+ The `Ref` caster sometimes creates a copy which needs to stay alive. This needs to
+ happen both for directs casts (just the array) or indirectly (e.g. list of arrays).
+ """
+ from pybind11_tests import get_elem_direct, get_elem_indirect
+
+ a = np.full(shape=10, fill_value=8, dtype=np.int8)
+ assert get_elem_direct(a) == 8
+
+ list_of_a = [a]
+ assert get_elem_indirect(list_of_a) == 8
+
+
def test_special_matrix_objects():
from pybind11_tests import incr_diag, symmetric_upper, symmetric_lower