fix problem with infinite recursion on coercion within constructors

dtool/src/interrogate/interfaceMakerPythonNative.cxx

@@ -856,12 +856,37 @@ write_class_details(ostream &out, Object * obj) {
     out << "       return -1;\n" ;
     out << "}\n";
 
+    out
+      << "int Dtool_InitNoCoerce_" << ClassName << "(PyObject *self, PyObject *args, PyObject *kwds) {\n"
+      << "  return Dtool_Init_" << ClassName << "(self, args, kwds);\n"
+      << "}\n\n";
+
   } else {
+    bool coercion_attempted = false;
     for (fi = obj->_constructors.begin(); fi != obj->_constructors.end(); ++fi) {
       Function *func = (*fi);
       std::string fname = "int Dtool_Init_"+ClassName+"(PyObject *self, PyObject *args, PyObject *kwds)";
       
-      write_function_for_name(out, obj, func,fname,"",ClassName);
+      write_function_for_name(out, obj, func,fname,"",ClassName, true, coercion_attempted);
+    }
+    if (coercion_attempted) {
+      // If a coercion attempt was written into the above constructor,
+      // then write a secondary constructor, that won't attempt any
+      // coercion.  We'll need this for nested coercion calls.
+      for (fi = obj->_constructors.begin(); fi != obj->_constructors.end(); ++fi) {
+        Function *func = (*fi);
+        std::string fname = "int Dtool_InitNoCoerce_"+ClassName+"(PyObject *self, PyObject *args, PyObject *kwds)";
+        
+        write_function_for_name(out, obj, func,fname,"",ClassName, false, coercion_attempted);
+      }
+    } else {
+      // Otherwise, since the above constructor didn't involve any
+      // coercion anyway, we can use the same function for both
+      // purposes.  Construct a trivial wrapper.
+      out
+        << "int Dtool_InitNoCoerce_" << ClassName << "(PyObject *self, PyObject *args, PyObject *kwds) {\n"
+        << "  return Dtool_Init_" << ClassName << "(self, args, kwds);\n"
+        << "}\n\n";
     }
   }
   
@@ -1657,7 +1682,8 @@ write_module_class(ostream &out, Object *obj) {
       }
       ostringstream forward_decl;
       string expected_params;
-      write_function_forset(out, obj, func, remaps, expected_params, 2, forward_decl, false, args_cleanup);
+      bool coercion_attempted = false;
+      write_function_forset(out, obj, func, remaps, expected_params, 2, forward_decl, false, true, coercion_attempted, args_cleanup);
       out << "  if (PyErr_Occurred() && PyErr_ExceptionMatches(PyExc_TypeError)) {\n";
       out << "    PyErr_Clear();\n";
       out << "  }\n";
@@ -1966,7 +1992,8 @@ void InterfaceMakerPythonNative::
 write_function_for_top(ostream &out, InterfaceMaker::Object *obj, InterfaceMaker::Function *func, const std::string &PreProcess) {
   std::string fname = "static PyObject *" + func->_name + "(PyObject *self, PyObject *args, PyObject *kwds)";
 
-  write_function_for_name(out, obj, func, fname, PreProcess, "");
+  bool coercion_attempted = false;
+  write_function_for_name(out, obj, func, fname, PreProcess, "", true, coercion_attempted);
 }
 
 ////////////////////////////////////////////////////////////////////
@@ -1978,7 +2005,7 @@ void InterfaceMakerPythonNative::
 write_function_for_name(ostream &out1, InterfaceMaker::Object *obj, InterfaceMaker::Function *func, 
                         const std::string &function_name, 
                         const std::string &PreProcess,
-                        const std::string &ClassName) {
+                        const std::string &ClassName, bool coercion_allowed, bool &coercion_attempted) {
   ostringstream forward_decl;
   ostringstream out;
 
@@ -2042,7 +2069,7 @@ write_function_for_name(ostream &out1, InterfaceMaker::Object *obj, InterfaceMak
     for (mii = MapSets.begin(); mii != MapSets.end(); mii ++) {
       indent(out, 2) << "case " << mii->first << ": {\n";
 
-      write_function_forset(out, obj, func, mii->second, expected_params, 4, forward_decl, is_inplace, "");
+      write_function_forset(out, obj, func, mii->second, expected_params, 4, forward_decl, is_inplace, coercion_allowed, coercion_attempted, "");
       if ((*mii->second.begin())->_type == FunctionRemap::T_constructor) {
         constructor = true;
       }
@@ -2107,7 +2134,7 @@ write_function_for_name(ostream &out1, InterfaceMaker::Object *obj, InterfaceMak
   } else {
     string expected_params = "";
     for (mii = MapSets.begin(); mii != MapSets.end(); mii++) {
-      write_function_forset(out, obj, func, mii->second, expected_params, 2, forward_decl, is_inplace, "");
+      write_function_forset(out, obj, func, mii->second, expected_params, 2, forward_decl, is_inplace, coercion_allowed, coercion_attempted, "");
       if ((*mii->second.begin())->_type == FunctionRemap::T_constructor) {
         constructor = true;
       }
@@ -2256,10 +2283,13 @@ write_function_forset(ostream &out, InterfaceMaker::Object *obj,
                       std::set<FunctionRemap *> &remapsin, 
                       string &expected_params, int indent_level, 
                       ostream &forward_decl, bool is_inplace,
+                      bool coercion_allowed,
+                      bool &coercion_attempted,
                       const string &args_cleanup) {
   // Do we accept any parameters that are class objects?  If so, we
   // might need to check for parameter coercion.
   bool coercion_possible = false;
+  if (coercion_allowed) {
     std::set<FunctionRemap *>::const_iterator sii;
     for (sii = remapsin.begin(); sii != remapsin.end() && !coercion_possible; ++sii) {
       FunctionRemap *remap = (*sii);
@@ -2285,6 +2315,7 @@ write_function_forset(ostream &out, InterfaceMaker::Object *obj,
         }
       }
     }
+  }
 
   if (coercion_possible) {
     // These objects keep track of whether we have attempted automatic
@@ -2326,7 +2357,7 @@ write_function_forset(ostream &out, InterfaceMaker::Object *obj,
         indent(out, indent_level) << "// -2 ";
         remap->write_orig_prototype(out, 0); out << "\n";
 
-        write_function_instance(out, obj, func, remap, expected_params, indent_level + 2, false, forward_decl, func->_name, is_inplace, coercion_possible, args_cleanup);
+        write_function_instance(out, obj, func, remap, expected_params, indent_level + 2, false, forward_decl, func->_name, is_inplace, coercion_possible, coercion_attempted, args_cleanup);
 
         indent(out, indent_level + 2) << "PyErr_Clear(); \n";
         indent(out, indent_level) << "}\n\n";            
@@ -2353,7 +2384,7 @@ write_function_forset(ostream &out, InterfaceMaker::Object *obj,
           << "// 1-" ;
         remap->write_orig_prototype(out, 0); 
         out << "\n" ;
-        write_function_instance(out, obj, func, remap, expected_params, indent_level + 2, true, forward_decl, func->_name, is_inplace, coercion_possible, args_cleanup);
+        write_function_instance(out, obj, func, remap, expected_params, indent_level + 2, true, forward_decl, func->_name, is_inplace, coercion_possible, coercion_attempted, args_cleanup);
 
         if (remap->_has_this && !remap->_const_method) {
           indent(out, indent_level)
@@ -2435,7 +2466,8 @@ write_function_instance(ostream &out, InterfaceMaker::Object *obj,
                         int indent_level, bool errors_fatal, 
                         ostream &ForwardDeclrs, 
                         const std::string &functionnamestr, bool is_inplace,
-                        bool coercion_possible, const string &args_cleanup) {
+                        bool coercion_possible, bool &coercion_attempted,
+                        const string &args_cleanup) {
   string format_specifiers;
   std::string keyword_list;
   string parameter_list;
@@ -2704,6 +2736,7 @@ write_function_instance(ostream &out, InterfaceMaker::Object *obj,
           // We never attempt to coerce a copy constructor parameter.
           // That would lead to infinite recursion.
           str << ", coerced_ptr, report_errors";
+          coercion_attempted = true;
         } else {
           str << ", NULL, true";
         }

dtool/src/interrogate/interfaceMakerPythonNative.h

@@ -86,18 +86,21 @@ private:
   
   void write_prototype_for_name(ostream &out, Function *func, const std::string &name);
   void write_prototype_for(ostream &out, Function *func);
-  void write_function_for_name(ostream &out, Object *obj, Function *func, const std::string &name, const std::string &PreProcess, const std::string &ClassName);
+  void write_function_for_name(ostream &out, Object *obj, Function *func, const std::string &name, const std::string &PreProcess, const std::string &ClassName,
+                               bool coercion_allowed, bool &coercion_attempted);
   void write_function_for_top(ostream &out, Object *obj, Function *func, const std::string &PreProcess);
   void write_function_instance(ostream &out, Object *obj, Function *func,
                                FunctionRemap *remap, string &expected_params, 
                                int indent_level, bool errors_fatal, 
                                ostream &forwarddecl, const std::string &functionnamestr,
-                               bool is_inplace, bool coercion_possible,
+                               bool is_inplace, bool coercion_allowed,
+                               bool &coercion_attempted,
                                const string &args_cleanup);
   
   void write_function_forset(ostream &out, Object *obj, Function *func,
                              std::set<FunctionRemap*> &remaps, string &expected_params,
                              int indent_level, ostream &forwarddecl, bool inplace,
+                             bool coercion_allowed, bool &coercion_attempted, 
                              const string &args_cleanup);
   
   void pack_return_value(ostream &out, int indent_level,

dtool/src/interrogatedb/dtool_super_base.cxx

@@ -83,4 +83,9 @@ int Dtool_Init_DTOOL_SUPER_BASE(PyObject *self, PyObject *args, PyObject *kwds)
   return -1;
 }
 
+int Dtool_InitNoCoerce_DTOOL_SUPER_BASE(PyObject *self, PyObject *args, PyObject *kwds) {
+  PyErr_SetString(PyExc_TypeError, "cannot init super base");
+  return -1;
+}
+
 #endif  // HAVE_PYTHON

dtool/src/interrogatedb/py_panda.cxx

@@ -71,9 +71,25 @@ attempt_coercion(PyObject *self, Dtool_PyTypedObject *classdef,
   if (coerced != NULL) {
     // Attempt coercion: try to create a temporary instance of the
     // required class using the supplied parameter.
-    PyObject *obj = PyObject_Call((PyObject *)classdef, self, NULL);
+    // Because we want to use the special InitNoCoerce constructor
+    // here instead of the regular constructor (we don't want to risk
+    // recursive coercion on the nested type we're creating), we have
+    // to call the constructor with a few more steps.
+    PyObject *obj = NULL;
+    if (classdef->_PyType.tp_new != NULL) {
+      obj = classdef->_PyType.tp_new(&classdef->_PyType, self, NULL);
+      assert(obj != NULL);
+      if (classdef->_Dtool_InitNoCoerce(obj, self, NULL) != 0) {
+        Py_DECREF(obj);
+        obj = NULL;
+      }
+    }
     if (obj == NULL) {
       // That didn't work; try to call a static "make" method instead.
+      // Presently, we don't bother filtering this for coercion,
+      // because none of our classes suffer from a recursion danger
+      // here.  Maybe one day we will need to also construct a
+      // makeNoCoerce wrapper?
       PyObject *make = PyObject_GetAttrString((PyObject *)classdef, "make");
       if (make != NULL) {
         PyErr_Clear();

dtool/src/interrogatedb/py_panda.h

@@ -139,6 +139,8 @@ typedef void * ( * ConvertFunctionType  )(PyObject *,Dtool_PyTypedObject * );
 typedef void * ( * ConvertFunctionType1  )(void *, Dtool_PyTypedObject *);
 typedef void   ( *FreeFunction  )(PyObject *);
 typedef void   ( *PyModuleClassInit)(PyObject *module);
+typedef int    ( *InitNoCoerce)(PyObject *self, PyObject *args, PyObject *kwds);
+
 //inline          Dtool_PyTypedObject *  Dtool_RuntimeTypeDtoolType(int type);
 inline void     Dtool_Deallocate_General(PyObject * self);
 //inline int      DTOOL_PyObject_Compare(PyObject *v1, PyObject *v2);
@@ -186,7 +188,8 @@ struct Dtool_PyTypedObject {
   ConvertFunctionType _Dtool_UpcastInterface;    // The Upcast Function By Slot
   ConvertFunctionType1 _Dtool_DowncastInterface; // The Downcast Function By Slot
   FreeFunction _Dtool_FreeInstance;
-  PyModuleClassInit _Dtool_ClassInit;            // The init function pointer
+  PyModuleClassInit _Dtool_ClassInit;            // The module init function pointer
+  InitNoCoerce _Dtool_InitNoCoerce;              // A variant of the constructor that does not attempt to perform coercion of its arguments.
 
   // some convenience functions..
   inline PyTypeObject &As_PyTypeObject() { return _PyType; };
@@ -245,7 +248,8 @@ struct Dtool_PyTypedObject {
       Dtool_UpcastInterface_##CLASS_NAME,                               \
       Dtool_DowncastInterface_##CLASS_NAME,                             \
       Dtool_FreeInstance_##CLASS_NAME,                                  \
-      Dtool_PyModuleClassInit_##CLASS_NAME                              \
+      Dtool_PyModuleClassInit_##CLASS_NAME,                             \
+      Dtool_InitNoCoerce_##CLASS_NAME                                   \
     };
 
 #if PY_MAJOR_VERSION >= 3
@@ -482,6 +486,7 @@ EXPCL_DTOOLCONFIG PyObject *DTool_CreatePyInstance(void *local_this, Dtool_PyTyp
 extern EXPORT_THIS   Dtool_PyTypedObject Dtool_##CLASS_NAME;\
 extern struct        PyMethodDef Dtool_Methods_##CLASS_NAME[];\
 int         Dtool_Init_##CLASS_NAME(PyObject *self, PyObject *args, PyObject *kwds);\
+int         Dtool_InitNoCoerce_##CLASS_NAME(PyObject *self, PyObject *args, PyObject *kwds);\
 PyObject *  Dtool_new_##CLASS_NAME(PyTypeObject *type, PyObject *args, PyObject *kwds);\
 void  *     Dtool_UpcastInterface_##CLASS_NAME(PyObject *self, Dtool_PyTypedObject *requested_type);\
 void  *     Dtool_DowncastInterface_##CLASS_NAME(void *self, Dtool_PyTypedObject *requested_type);\