[vtk-developers] VTK 4.2.4 and VTK 5

[Ken Martin]

Hi Prabhu,

> From: Prabhu Ramachandran [mailto:prabhu at aero.iitm.ernet.in]
> A few thoughts (might end up being flames though).
> 
>  1. There are Python related issues that were fixed in the recent
>     past.  Wrapping/Python/vtk/tk/vtkLoadPythonTkWidgets.py does not
>     work under Python2.3 because the darned Python developers changed
>     Tkinter behavior so that interp.getvar('auto_path') returns a
>     tuple instead of a string.  These do not show up in the 4 tree and
>     consequently you can't use the Tk widgets with VTK 4.  Serious
>     pain in the neck.  Similarly there were the dlopen related fixes
>     made to Wrapping/Python/vtk/__init__.py that don't show up in that
>     tree.

I'm not a Python developer so I do not know what critical python changes
have been made since 4.2, but I'd be happy to merge/update the branch files
to match the CVS files. I just need someone with Python/VTK knowledge to say
"update these few files from CVS" and I'll do it. 

>  2. I am not for tracking yet another branch (due to lack of disk
>     space and time), so am not volunteering to even make the changes
>     on the 4 branch.  I would have appreciated if we were informed
>     before the branch was made so I could have told you about this.

If you are planning to move forward to VTK 5 in the future then there is no
reason to be involved with the VTK4 tree. Now the VTK 4.2 branch of the main
tree (different from the VTK4 tree) is the latest release and if there have
been critical fixes (not new features) made in VTK CVS then they should have
been reported to me (or noticed by me) so I could merge them into the
release. VTK 4.2 is the current release and is what most/all non developers
should be using. If it doesn't work with Python 2.3 then that should have
been addressed. Does that make sense?

I agree you should have been informed. There were some earlier email
discussions on this subject but they were not on vtk-developers and I didn't
really pay attention to what was on vtk developers and what wasn't. But the
discussion can certainly continue. Nothing is set in stone at this point. 

> When will 5 become stable or when will 4.4 be released?  Without a
> serious timeline its going to be a pain for users to decide which
> release/version to use.  How unstable will CVS be?  Checking the
> dashboards is too much work for the average user.  Its a bit much
> asking users to even build VTK, asking them to track CVS is worse.
> Also what is wrong with the current 4.3 tree, without backwards
> incompatible changes?  Why not make that the default, let it stabilize
> and branch off from there?

My guess is that VTK 5 will become stable around the middle of 2004. We will
try to keep CVS stable but no average users should be using CVS. The point
of having the releases (4.2) and patch releases (4.2.3, 4.2.4, etc) is to
provide a tested stable version of VTK so that people who need a working
version of VTK don't have to mess around with checking the dashboards. The
only exception to this is when someone needs a new feature that is in CVS
but not in the release. In those cases if it is a key feature that is
unlikely to cause problems we will add it to the VTK 4.2 branch. 

Why not make a new release from what is in CVS right now? Because the
release process takes a lot of effort and the amount of "added value" in VTK
4.3 doesn't warrant it in my opinion. I'd rather perform minor updates to
the 4.2 branch and put the effort into getting VTK 5 done.

Thanks
Ken