Return str to a callback raise a segfault if used in string formating

[Vincent Vande Vyvre]

Le 13/10/17 à 12:39, Paul Moore a écrit :
> As a specific suggestion, I assume the name of the created file is a
> string object constructed in the C extension code, somehow. The fact
> that you're getting the segfault with some uses of that string
> (specifically, passing it to %-formatting) suggests that there's a bug
> in the C code that constructs that string. That's where I'd start by
> looking. Maybe something isn't zero-terminated that should be? Maybe
> your code doesn't set up the character encoding information correctly?
>
> Paul
That was my first idea, because I can verify the instance of PyUnraw is 
not destroyed when I use the file name, but I was in trouble by the 
usage of the file name in string formatting.

For example I can use the file name into the slot i.e. 
shutil.copy(fname, "path/renamed.tiff")
The file is correctly copied.

In fact, I can do anything with the file name except use it in string 
formatting, then your approach is probably a good way.

Into the CPython part I have a c-string pythonized by:
     temp = self->outfname;
     self->outfname = PyUnicode_FromString(ofname);
     Py_XDECREF(temp);

and exposed to Python with:
static PyMemberDef PyUnraw_members[] = {
     {"out_file", T_OBJECT_EX, offsetof(PyUnraw, outfname), 0,
      "Path of the decoded file"},
     ...

Vincent