Re: [PyOpenGL-Users] bug: glVertex2fv(None) segfaults

[Mike C. F. <mcf...@ro...>]

Okay, I've added a check typemap for this that appears to solve the 
problem.  Looking at the code, I can see at least a few more instances 
where Tarn wasn't checking for array-size/non-null conditions, so 
there's at least a few more situations like this that will arise.  For 
now, anything which is defined as having "sometype *v" as it's signature 
is getting void-checked and raising an error on that condition.

Why didn't I just modify the conversion routine?

    There may be situations where the declaration *shouldn't* be
    null-checked (that is, where NULL is a valid input), i.e. the fix
    may actually break some code and making it easy to fix those
    situations requires that the conversion routine not include the
    checking support.  The entire OpenGLContext test suite passes (at
    least, runs as expected) with the changes, so it seems to work in
    the common cases, anyway.

As a note, introducing this finally explained a long-standing bug with a 
test-script, namely that a missing combine callback to GLU's 
tessellation mechanism was returning a None, so was passing a NULL 
pointer to gluVertex2fv.

Thanks for the report,
Mike

Maciej Kalisiak wrote:

>Quick disclaimer: I haven't updated my PyOpenGL in some time; version file
>shows 2.0.1.03.  Alas, updating right now is not an option (lack of time,
>especially if upgrade doesn't go smoothly)
>
>I've noticed that glVertex2fv, and quite possibly the other vector forms of
>glVertex, do not handle gracefully the case when they are (erroneously) handed
>"None" instead of an actualy vector/sequence.  I get a segfault; an exception
>(i.e., arg checking code) would be much more helpful.
>
>It could be that this is fixed in the latest versions of pyopengl, which I
>haven't tried, but I'm mailing this on the off chance that it isn't... it seems
>to me to be a rather rare bug, hence likely still present.
>  
>
________________________________________________
  Mike C. Fletcher
  Designer, VR Plumber, Coder
  http://www.vrplumber.com
  http://blog.vrplumber.com