[Phoenix Issue] wx.FlexGridSizer.AddGrowableCol results in C++ assert

*Summary*
 
Environment: wxPython Phoenix, head of master branch, Windows 7 64-bit, 
Python 3.4.3.
 

The error can be reproduced in the GenericDirCtrl demo of the wxPython demo 
application. The following is a snippet of code from the demo around the 
source of the error.

    sz = wx.FlexGridSizer(cols=3, hgap=5, vgap=5)
    sz.Add((35, 35))  # some space above
    sz.Add((35, 35))
    sz.Add((35, 35))

    sz.Add(txt1)
    sz.Add(txt2)
    sz.Add(txt3)

    sz.Add(dir1, 0, wx.EXPAND)
    sz.Add(dir2, 0, wx.EXPAND)
    sz.Add(dir3, 0, wx.EXPAND)

    sz.Add((35,35))  # some space below

    sz.AddGrowableRow(2)
    sz.AddGrowableCol(0)  # <-- error here
    sz.AddGrowableCol(1)
    sz.AddGrowableCol(2)

The error is :

    "!m_cols || idx < (size_t)m_cols" failed at 
..\..\src\common\sizer.cpp(1980)
    in wxFlexGridSizer::AddGrowableCol(): invalid column index

*Details*
 
I've done some poking around to try and diagnose the problem. Here are some 
observation.
 
(1)
 
In Python, if you specify the named argument, it works. For example:

    sz.AddGrowableCol(0, proportion=0)

Although, this does not:

    sz.AddGrowableCol(0, 0)

(2)
 
The C++, wxWidgets, version of the demo works as expected.
 
(3)
 
At the C++ level in wxWidgets, when AddGrowableCol(size_t idx, int 
proportion) is called, the value of idx equals some super large number (as 
reported by the C++ debugger), hence the reason the C++ assert fails 
(perhaps idx is uninitialized?).
 
(4)
 
If I insert a printf("idx=%d\n", idx) to see the value of the idx inside 
the SIP generated wrapper function meth_wxFlexGridSizer_AddGrowableRow() 
(source file sip\cpp\sip_corewxFlexGridSizer.cpp), sz.AddGrowableCol() in 
Python works (hence the demo) works. Remove the printf() and it does not.
 

    static PyObject *meth_wxFlexGridSizer_AddGrowableRow(PyObject *sipSelf, 
PyObject *sipArgs, PyObject *sipKwds)
    {
        PyObject *sipParseErr = NULL;

        {
            size_t idx;
            int proportion = 0;
            wxFlexGridSizer *sipCpp;

            static const char *sipKwdList[] = {
                sipName_idx,
                sipName_proportion,
            };

            if (sipParseKwdArgs(&sipParseErr, sipArgs, sipKwds, sipKwdList, 
NULL, "Bm|i", &sipSelf, sipType_wxFlexGridSizer, &sipCpp, &idx, 
&proportion))
            {
                PyErr_Clear();

                *printf("idx=%d\n", idx)*
                sipCpp->AddGrowableRow(idx,proportion);

                if (PyErr_Occurred())
                    return 0;

                Py_INCREF(Py_None);
                return Py_None;
            }
        }

        /* Raise an exception if the arguments couldn't be parsed. */
        sipNoMethod(sipParseErr, sipName_FlexGridSizer, 
sipName_AddGrowableRow, NULL);

        return NULL;
    }

(5)
 
wx.Sizer.InsertStretchSpace() also asserts for the similar reason of the 
index argument being a large number.  Coincidently, it has the same calling 
signature. 

Before I attempt to probe this any further, does anyone have any idea what 
might be going on?

 

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