[Mesa-dev] [PATCH 3/3] mesa: Remove extra NULL Check on glFeedbackBuffer().

[Eric Anholt]

On Tue, 28 Jun 2011 21:20:14 -0600, Brian Paul <brian.e.paul at gmail.com> wrote:
> On Tue, Jun 28, 2011 at 5:49 PM, Eric Anholt <eric at anholt.net> wrote:
> > This error result doesn't appear in the GL 2.1 or 3.2 compatibility
> > specs, and triggers an unexpected GL error in Intel's oglconform when
> > it tries to reset the feedback state after usage so that the "diff the
> > state at error time vs. context init time" code doesn't generate
> > spurious diffs.  The unexpected GL error then translates into testcase
> > failure.
> > ---
> >  src/mesa/main/feedback.c |    5 -----
> >  1 files changed, 0 insertions(+), 5 deletions(-)
> >
> > diff --git a/src/mesa/main/feedback.c b/src/mesa/main/feedback.c
> > index fcb089f..f4862f5 100644
> > --- a/src/mesa/main/feedback.c
> > +++ b/src/mesa/main/feedback.c
> > @@ -64,11 +64,6 @@ _mesa_FeedbackBuffer( GLsizei size, GLenum type, GLfloat *buffer )
> >       _mesa_error( ctx, GL_INVALID_VALUE, "glFeedbackBuffer(size<0)" );
> >       return;
> >    }
> > -   if (!buffer) {
> > -      _mesa_error( ctx, GL_INVALID_VALUE, "glFeedbackBuffer(buffer==NULL)" );
> > -      ctx->Feedback.BufferSize = 0;
> > -      return;
> > -   }
> >
> >    switch (type) {
> >       case GL_2D:
> 
> You're removing the null ptr check which set the buffer size to zero.
> What if someone passes buffer=NULL but size > 0?  I hope we don't
> crash now if we didn't crash before.  Though, I doubt that'd ever
> happen in practice.

I'm sure we would, and I'd just chalk it up to application bugs like so
many other entrypoints with a pointer==NULL.  I guess we can just limit
the check to size != NULL if you'd like.
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