Fix typecheck typemaps for non-pointers and NULL

The typecheck typemaps succeed for non pointers (SWIGTYPE, SWIGTYPE&,
SWIGTYPE&&) when the equivalent to C NULL is passed from the target
language. This commit implements a fix for Python to not accept a Python
None for non-pointer types.

Issue #1202

Examples/test-suite/python/implicittest_runme.py

@@ -13,15 +13,7 @@ check(1, A(1).get())
 check(2, A(1.0).get())
 check(3, A(B()).get())
 check(4, A("hello").get())
-try:
+check(4, A(None).get())
-    check(3, A(None).get())
-    raise RuntimeError
-except ValueError:
-    # ValueError: invalid null reference in method 'new_A', argument 1 of type 'B const &'
-    # Arguably A(char *) should be chosen, but there is a bug to do with None passed to methods overloaded by value,
-    # references and pointers to different types, where pointers ought to be
-    # given a slightly higher precedence.
-    pass
 
 check(1, get(1))
 check(2, get(1.0))

Lib/python/pyrun.swg

@@ -1018,7 +1018,7 @@ SWIG_Python_ConvertPtrAndOwn(PyObject *obj, void **ptr, swig_type_info *ty, int
   if (obj == Py_None && !implicit_conv) {
     if (ptr)
       *ptr = 0;
-    return SWIG_OK;
+    return (flags & SWIG_POINTER_NO_NULL) ? SWIG_NullReferenceError : SWIG_OK;
   }
 
   res = SWIG_ERROR;

Lib/swigrun.swg

@@ -43,6 +43,7 @@
 /* Flags for pointer conversions */
 #define SWIG_POINTER_DISOWN        0x1
 #define SWIG_CAST_NEW_MEMORY       0x2
+#define SWIG_POINTER_NO_NULL       0x4
 
 /* Flags for new pointer objects */
 #define SWIG_POINTER_OWN           0x1

Lib/typemaps/swigtype.swg

@@ -358,46 +358,46 @@
 
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1) SWIGTYPE & {
   void *vptr = 0;
-  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, 0);
+  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, SWIG_POINTER_NO_NULL);
   $1 = SWIG_CheckState(res);
 }
 
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1) SWIGTYPE && {
   void *vptr = 0;
-  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, 0);
+  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, SWIG_POINTER_NO_NULL);
   $1 = SWIG_CheckState(res);
 }
 
 #if defined(__cplusplus) && defined(%implicitconv_flag)
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1,implicitconv=1) const SWIGTYPE & {
-  int res = SWIG_ConvertPtr($input, 0, $descriptor, %implicitconv_flag);
+  int res = SWIG_ConvertPtr($input, 0, $descriptor, SWIG_POINTER_NO_NULL | %implicitconv_flag);
   $1 = SWIG_CheckState(res);
 }
 
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1,implicitconv=1) const SWIGTYPE && {
-  int res = SWIG_ConvertPtr($input, 0, $descriptor, %implicitconv_flag);
+  int res = SWIG_ConvertPtr($input, 0, $descriptor, SWIG_POINTER_NO_NULL | %implicitconv_flag);
   $1 = SWIG_CheckState(res);
 }
 
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1,implicitconv=1) SWIGTYPE {
-  int res = SWIG_ConvertPtr($input, 0, $&descriptor, %implicitconv_flag);
+  int res = SWIG_ConvertPtr($input, 0, $&descriptor, SWIG_POINTER_NO_NULL | %implicitconv_flag);
   $1 = SWIG_CheckState(res);
 }
 #else
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1) const SWIGTYPE & {
   void *vptr = 0;
-  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, 0);
+  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, SWIG_POINTER_NO_NULL);
   $1 = SWIG_CheckState(res);
 }
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1) const SWIGTYPE && {
   void *vptr = 0;
-  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, 0);
+  int res = SWIG_ConvertPtr($input, &vptr, $descriptor, SWIG_POINTER_NO_NULL);
   $1 = SWIG_CheckState(res);
 }
 
 %typemap(typecheck,precedence=SWIG_TYPECHECK_POINTER,noblock=1) SWIGTYPE {
   void *vptr = 0;
-  int res = SWIG_ConvertPtr($input, &vptr, $&descriptor, 0);
+  int res = SWIG_ConvertPtr($input, &vptr, $&descriptor, SWIG_POINTER_NO_NULL);
   $1 = SWIG_CheckState(res);
 }
 #endif