Reduced further after finding #4549

pybind/pybind11#4549

main.cc

@@ -1,70 +1,43 @@
 #include <iostream>
+#include <memory>
 
 #include <pybind11/pybind11.h>
 
 namespace py = pybind11;
 
-class MyContext {
- public:
-  MyContext() : msg_("Can I be a mongoose dog?") {
-    std::cerr << "Context Constructor: " << (void*) this << std::endl;
-  }
-
-  ~MyContext() {
-    std::cerr << "Context Destructor: " << (void*) this << std::endl;
-  }
-
- std::string get() const {
-  return msg_;
- }
-
- private:
-  std::string msg_;
+struct Test {
+ Test(const std::string& val) : val_(val) {}
+ std::string val_;
 };
 
-class MyGroup {
+class ErrorTest {
  public:
-  MyGroup(const MyContext& ctx, const std::string& uri) : ctx_(ctx), uri_(uri) {
-    std::cerr << "Group Constructor: " << (void*) this << std::endl;
-    std::cerr << "Group Context: " << (void*) &ctx_ << std::endl;
-    throw std::runtime_error("Look! A squirrel!");
+  ErrorTest(const std::string& mesg)
+      : test_(std::make_shared<Test>(mesg)) {
+    std::cerr << "Constructor: " << (void*) this << std::endl;
+    throw std::runtime_error("");
   }
 
-  ~MyGroup() {
-    std::cerr << "Group Destructor: " << (void*) this << std::endl;
+  ~ErrorTest() {
+    std::cerr << "Destructor: " << (void*) this << std::endl;
   }
 
-  std::string dump(bool) {
-    return ctx_.get();
+  std::string repr() {
+    return test_->val_;
   }
 
  private:
-  const MyContext& ctx_;
-  std::string uri_;
+  std::shared_ptr<Test> test_;
 };
 
-void init_context(py::module &m) {
-  py::class_<MyContext>(m, "Context")
-      .def(py::init());
-}
-
-std::string do_dump(MyGroup& group, bool recursive) {
-  std::cerr << "DUMPING GROUP: " << (void*) &group << std::endl;
-  auto ret = group.dump(recursive);
-  std::cerr << "FINISHED DUMPING GROUP: " << (void*) &group << std::endl;
-  return ret;
-}
-
 void init_group(py::module &m) {
-  py::class_<MyGroup>(m, "Group")
-      .def(
-          py::init<const MyContext &, const std::string &>(),
-          py::keep_alive<1, 2>())
-      .def("_dump", do_dump);
+
 }
 
 PYBIND11_MODULE(errortest, m) {
-    m.doc() = "Test exceptions from contructors";
-    init_context(m);
-    init_group(m);
+  m.doc() = "Test exceptions from contructors";
+
+  py::class_<ErrorTest>(m, "ErrorTest")
+    .def(py::init<const std::string &>())
+    .def("__repr__", &ErrorTest::repr);
 }

requirements.txt

@@ -1,2 +1 @@
 pybind11
-pytest

run.sh

@@ -8,4 +8,4 @@ python3 -m venv venv
 source venv/bin/activate
 pip install -r requirements.txt
 python setup.py develop
-pytest --capture=no tests.py
+python tests.py

tests.py

@@ -1,22 +1,11 @@
-import pytest
-
 import errortest
 
-class Group(errortest.Group):
-    def __init__(self, uri):
-        try:
-            ctx = errortest.Context()
-            super().__init__(ctx, uri)
-        except Exception as exc:
-            print(exc)
-            raise
-
-    def __repr__(self):
-        return self._dump(True)
+class Derived(errortest.ErrorTest):
+    pass
 
-def test_invalid_object_type():
-    path = "not_a_group"
-    with pytest.raises(ValueError):
-        # Should return error that uri is not a Group
-        group = Group(uri=path)
+def test_new():
+    g = Derived.__new__(Derived)
+    print(repr(g))
 
+if __name__ == "__main__":
+    test_new()