get rid of recursive dispatch; simplify, and get expected results

Author: EricCousineau-TRI

tests/test_issue1552.cpp

@@ -8,16 +8,12 @@ class Dispatcher;
 class Client
 {
 public:
-    Client(Dispatcher* disp): PtrD(disp)
+    Client()
     {
         std::cout << "In Client::Client\n";
     }
     virtual ~Client(){};
-    virtual void ProcessEvent()
-    {
-        std::cout << "THIS SHOULDN'T HAPPEN --In Client::ProcessEvent\n";
-    }
-    Dispatcher* PtrD;
+    virtual void ProcessEvent() = 0;
 };
 
 class Dispatcher
@@ -27,7 +23,6 @@ class Dispatcher
     {
         std::cout << "In Dispatcher::Dispatcher\n";
     }
-    virtual ~Dispatcher(){};
 
     void Dispatch(Client* client)
     {
@@ -36,31 +31,24 @@ class Dispatcher
     }
 };
 
-class DispatcherTrampoline : public Dispatcher
-{
-public:
-    using Dispatcher::Dispatcher;
-};
-
 class ClientTrampoline : public Client
 {
 public:
     using Client::Client;
 
     void ProcessEvent() override
     {
-        PYBIND11_OVERLOAD(void,Client,ProcessEvent,);
+        PYBIND11_OVERLOAD_PURE(void,Client,ProcessEvent,);
     }
 };
 
 TEST_SUBMODULE(issue1552, m)
 {
     py::class_<Client,ClientTrampoline> cli(m,"Client");
-    cli.def(py::init<Dispatcher* >());
+    cli.def(py::init());
     cli.def("ProcessEvent",&Client::ProcessEvent);
-    cli.def_readwrite("PtrD",&Client::PtrD);
 
-    py::class_<Dispatcher,DispatcherTrampoline> dsp(m,"Dispatcher");
+    py::class_<Dispatcher> dsp(m,"Dispatcher");
     dsp.def(py::init< >());
     dsp.def("Dispatch",&Dispatcher::Dispatch);
 }

tests/test_issue1552.py

@@ -5,17 +5,16 @@
 
 
 class SomeClient(m.Client):
-    def __init__(self,d):
+    def __init__(self):
         print("In SomeClient::__init__")
-        super().__init__(d);
+        super().__init__()
 
     def ProcessEvent(self):
-        print("in SomeClient::ProcessEvent,about to call self.ProcessEvent")
-        self.PtrD.Dispatch(self);
+        print("Python ProcessEvent")
 
 
 def test_main():
     # https://github.com/pybind/pybind11/issues/1552
     dd = m.Dispatcher()
-    cl = SomeClient(dd)
+    cl = SomeClient()
     dd.Dispatch(cl)