From d22205554479d22502d8eaef60ca01345744a15d Mon Sep 17 00:00:00 2001
From: Jeremy Nimmer <jeremy.nimmer@tri.global>
Date: Sat, 11 Nov 2023 12:43:40 -0800
Subject: [PATCH] [eigen] Obey noconvert() in Eigen::Sparse type type caster
 (#69)

---
 include/pybind11/eigen/matrix.h | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/pybind11/eigen/matrix.h b/include/pybind11/eigen/matrix.h
index 8d4342f81..22b8bf09b 100644
--- a/include/pybind11/eigen/matrix.h
+++ b/include/pybind11/eigen/matrix.h
@@ -649,7 +649,7 @@ struct type_caster<Type, enable_if_t<is_eigen_sparse<Type>::value>> {
     using Index = typename Type::Index;
     static constexpr bool rowMajor = Type::IsRowMajor;
 
-    bool load(handle src, bool) {
+    bool load(handle src, bool convert) {
         if (!src) {
             return false;
         }
@@ -659,6 +659,9 @@ struct type_caster<Type, enable_if_t<is_eigen_sparse<Type>::value>> {
         object matrix_type = sparse_module.attr(rowMajor ? "csr_matrix" : "csc_matrix");
 
         if (!type::handle_of(obj).is(matrix_type)) {
+            if (!convert) {
+                return false;
+            }
             try {
                 obj = matrix_type(obj);
             } catch (const error_already_set &) {