Fix handling of NULL default argument values for pointer types.

Accept not only manifest pointer types (such as e.g. "void *") but also types
that are typedefs for pointer types when checking whether C++ value of 0 must
be represented as 0 or None in Python.

Closes #365, #376.

CHANGES.current

@@ -5,6 +5,9 @@ See the RELEASENOTES file for a summary of changes in each release.
 Version 3.0.6 (in progress)
 ===========================
 
+2015-04-23: vadz
+            [Python] Fix the use of default values for the pointer types (#365, #376).
+
 2015-04-23: wsfulton
             Fix 'make check-ccache' which is part of 'make check' when one of the CCACHE_
             environment variables, for example CCACHE_DISABLE, is set.

Examples/test-suite/default_args.i

@@ -115,6 +115,7 @@
 %rename(renamed1arg) Foo::renameme() const;
 
 %inline %{
+  typedef void* MyHandle;
 
   // Define a class
   class Foo {
@@ -139,6 +140,10 @@
       // test the method itself being renamed
       void oldname(int x = 1234) {}
       void renameme(int x = 1234, double d=123.4) const {}
+
+      // test default values for pointer arguments
+      int double_if_void_ptr_is_null(int n, void* p = NULL) { return p ? n : 2*n; }
+      int double_if_handle_is_null(int n, MyHandle h = 0) { return h ? n : 2*n; }
   };
   int Foo::bar = 1;
   int Foo::spam = 2;

Examples/test-suite/python/default_args_runme.py

@@ -31,6 +31,17 @@ def run(module_name):
   f.newname()
   f.newname(1)
 
+  if f.double_if_void_ptr_is_null(2, None) != 4:
+    raise RuntimeError
+
+  if f.double_if_void_ptr_is_null(3) != 6:
+    raise RuntimeError
+
+  if f.double_if_handle_is_null(4, None) != 8:
+    raise RuntimeError
+
+  if f.double_if_handle_is_null(5) != 10:
+    raise RuntimeError
 
   try:
     f = default_args.Foo(1)

Source/Modules/python.cxx

@@ -1827,6 +1827,20 @@ public:
     return doc;
   }
 
+  /* ------------------------------------------------------------
+   * isPointerType()
+   *   Return true if the given type is a pointer after resolving
+   *   it if it's a typedef. This should be typically used instead
+   *   of SwigType_ispointer(), unless the type is already resolved.
+   * ------------------------------------------------------------ */
+  static bool isPointerType(SwigType* t) {
+    SwigType* const full_type = SwigType_typedef_resolve_all(t);
+    bool const ispointer = SwigType_ispointer(full_type);
+    Delete(full_type);
+
+    return ispointer;
+  }
+
   /* ------------------------------------------------------------
    *  convertDoubleValue()
    *    Check if the given string looks like a decimal floating point constant
@@ -1922,7 +1936,7 @@ public:
 	if (Len(v) == 1) {
 	  // This is just a lone 0, but it needs to be represented differently
 	  // in Python depending on whether it's a zero or a null pointer.
-	  if (SwigType_ispointer(t))
+	  if (isPointerType(t))
 	    return NewString("None");
 	  else
 	    return v;
@@ -1959,7 +1973,7 @@ public:
     if (Strcmp(v, "false") == 0 || Strcmp(v, "FALSE") == 0)
       return NewString("False");
     if (Strcmp(v, "NULL") == 0 || Strcmp(v, "nullptr") == 0)
-      return SwigType_ispointer(t) ? NewString("None") : NewString("0");
+      return isPointerType(t) ? NewString("None") : NewString("0");
 
     // This could also be an enum type, default value of which could be
     // representable in Python if it doesn't include any scope (which could,