Re: [PATCH, GDB] Fix Windows gdb build failure with python support

[Pedro Alves <palves@redhat.com>]

On 04/06/2017 03:28 PM, Thomas Preudhomme wrote:
> 
> 
> GDB fails to build for Windows host with python support enabled due to

Uppercase "Python", and would be a good idea to mention that this is
Python 2.

> python_file's second argument 

It's actually PyFile_FromString's second parameter, not python_file's.
"python_file" is a reference that is being initialized from the result
of PyFile_FromString.

> being of type char * and being passed a
> string litteral. 

Typo "literal".

> This patch takes the conservative assumptions that the
> function might indeed modify the character string and use a local char
> array to pass the mode instead.

The Python API is notoriously buggy wrt to const-correctness when
it comes to string parameters.

Note that in gdb/python/python-internal.h, we have fixups for all of:

 PyObject_GetAttrString
 PyObject_HasAttrString
 PyObject_CallMethod
 PyErr_NewException
 PySys_GetObject
 PySys_SetPath
 PyGetSetDef
 PyArg_ParseTupleAndKeywords

Over the years it's been getting better.

A few of those were added just yesterday, but I didn't build Windows
with Python so I missed this one.

Now, this API in particular seems to have been removed completely
in Python 3, so there's no "it was fixed in 3.x" that we could put
in a comment.  Anyway, since this is just one single place, let's just
not bother with anything fancy.

Please just add a cast instead (and update the commit log accordingly):

  PyFile_FromString (full_path.get (), (char *) "r")

OK with that change.

Thanks,
Pedro Alves