POC test for #2847

tests/pybind11_cross_module_tests.cpp

@@ -9,6 +9,7 @@
 
 #include "pybind11_tests.h"
 #include "local_bindings.h"
+#include "test_exceptions.h"
 #include <pybind11/stl_bind.h>
 #include <numeric>
 
@@ -30,6 +31,13 @@ PYBIND11_MODULE(pybind11_cross_module_tests, m) {
     m.def("throw_pybind_value_error", []() { throw py::value_error("pybind11 value error"); });
     m.def("throw_pybind_type_error", []() { throw py::type_error("pybind11 type error"); });
     m.def("throw_stop_iteration", []() { throw py::stop_iteration(); });
+    py::register_exception_translator([](std::exception_ptr p) {
+      try {
+          if (p) std::rethrow_exception(p);
+      } catch (const tmp_e &e) {
+          PyErr_SetString(PyExc_KeyError, e.what());
+      }
+    });
 
     // test_local_bindings.py
     // Local to both:

tests/test_exceptions.cpp

@@ -7,6 +7,7 @@
     BSD-style license that can be found in the LICENSE file.
 */
 
+#include "test_exceptions.h"
 #include "pybind11_tests.h"
 
 // A type that should be raised as an exception in Python
@@ -228,4 +229,5 @@ TEST_SUBMODULE(exceptions, m) {
     // Test repr that cannot be displayed
     m.def("simple_bool_passthrough", [](bool x) {return x;});
 
+    m.def("throw_", []() { throw tmp_e(); });
 }

tests/test_exceptions.h

@@ -0,0 +1,12 @@
+#pragma once
+#include "pybind11_tests.h"
+#include <stdexcept>
+
+// shared exceptions for cross_module_tests
+
+class PYBIND11_EXPORT tmp_e : public pybind11::builtin_exception {
+public:
+    using builtin_exception::builtin_exception;
+    explicit tmp_e() : tmp_e("") {}
+    void set_error() const override { PyErr_SetString(PyExc_RuntimeError, what()); }
+};

tests/test_exceptions.py

@@ -43,6 +43,9 @@ def test_cross_module_exceptions():
     with pytest.raises(StopIteration) as excinfo:
         cm.throw_stop_iteration()
 
+    with pytest.raises(KeyError) as excinfo:
+        m.throw_()
+
 
 def test_python_call_in_catch():
     d = {}