[Bf-committers] Updated BMesh Merge Proposal

[Campbell Barton]

On Mon, Jan 2, 2012 at 7:51 AM, Knapp <magick.crow at gmail.com> wrote:
> On Sun, Jan 1, 2012 at 1:08 PM, David Jeske <davidj at gmail.com> wrote:
>> Getting my 2 cents in on an old thread...
>>
>> On Dec 2, 2011 3:29 PM, "Campbell Barton" <ideasman42 at gmail.com> wrote:
>>> There are many options here, I was going to list all the ones I could
>>> think of but most have some fairly annoying drawbacks.
>>
>> You missed one of the best ones imo...
>>
>> New '2.6' is made 3.0 beta, including a new .blend3 file extension which
>> has a different file association and header so old blender versions
>> wouldn't even try to load it. Users can manually export legacy .blend files
>> from 2.6 (3.0) with various caveats.
>>
>> Writing files which people will think should work but will just crash old
>> blender seems like a 'colosally bad idea'. It will only further cement
>> blender's status as an unreliable amateur hobbiest tool. Blender should
>> never crash.
>
> I think he has a good point. I don't personally care if blender
> clashes when old programs try and load new blender blend files but I
> might be nice to have the new blender versions have code that does
> something like:
>
> Load file, check compatibility variable and if it fails print contained message.
>
> So the  file header might have
>
> (works with) 2.5.5 to 2.8, (if not in this range than print) "error
> massage". The error massage might contain some helpful info like how
> the file might be converted to work etc.
>
> This will prevent blender of the future from ever having  to face this
> choice again.
>
> I also think that move from the old system to Bmesh is a big enough
> change to warrant a big version number change or even as he suggested
> a new blender extension.
>
> Antony Riakiotakis, what do you mean by not this again?
>
> --
> Douglas E Knapp

We already have a MIN_VERSION variable thats saved into the blend
file, this is used to give a warning message on load that things might
not work right.

The way this would be used is BMesh blender will save its blend files
as MINVERSION=2.62, so 2.61 will popup a warning on load.
then at least users have been warned.

I think this is enough - we could disable loading the file at all and
then blender wont crash - or only allow loading when --debug is passed
for people who know what there doing. not sure its worthwhile -
 people are warned and they can upgrade there blender.

- Campbell