Add a stream parameter to gc.set_debug

http://bugs.python.org/issue5851

[amaury, 2009-08-25 07:07:20]

The patch is complete, tests and doc... Thanks!

It won't apply to py3k, though: python 3 does not use FILE* any more.
I suggest to accept any file-like objects (e.g StringIO) and use the "write"
method. But I don't know if calling python code there can interfere with the
garbage collector.

http://codereview.appspot.com/110078/diff/1/4
File Doc/library/gc.rst (right):

http://codereview.appspot.com/110078/diff/1/4#newcode60
Line 60: descriptor to which debugging information will be written. See below
for a
better say: "a file object"

http://codereview.appspot.com/110078/diff/1/6
File Modules/gcmodule.c (right):

http://codereview.appspot.com/110078/diff/1/6#newcode704
Line 704: FILE* file = PyFile_AsFile((PyObject*) debug_output);
PyFile_AsFile does not exist with python 3. (py3 files have no FILE*) Is it
possible to use the 'write' method directly? Or is it forbidden from inside the
garbage collector?

[nicdumz, 2009-08-25 10:26:30]

Here is an updated patch.

Who can we nosy to get feedback on the appropriateness of calling a Python
function inside debug_print?

Thanks :)

http://codereview.appspot.com/110078/diff/1/4
File Doc/library/gc.rst (right):

http://codereview.appspot.com/110078/diff/1/4#newcode60
Line 60: descriptor to which debugging information will be written. See below
for a
On 2009/08/25 07:07:20, amauryfa wrote:
> better say: "a file object"

Done.

http://codereview.appspot.com/110078/diff/1/6
File Modules/gcmodule.c (right):

http://codereview.appspot.com/110078/diff/1/6#newcode704
Line 704: FILE* file = PyFile_AsFile((PyObject*) debug_output);
On 2009/08/25 07:07:20, amauryfa wrote:
> PyFile_AsFile does not exist with python 3. (py3 files have no FILE*) Is it
> possible to use the 'write' method directly? Or is it forbidden from inside
the
> garbage collector?

Done. I am accessing the write method directly in set_debug to minimize the
Python code running in debug_print.
I am not sure If it's safe to call a function from inside the gc: I'm not
qualified enough to answer that question :)

Since we use stream.write now, we can potentially run arbitrary code there. If
it's not safe, is there is any mechanism in py3 that would allow us to use a
vfprintf-like on a file object? To avoid running any Python code at all?