[Bf-committers] Support for 32-bit architectures

[Sergey Sharybin]

Hi,

I think Sybren will bring some points here, so I will try not to interfere
with those to not create too much noise here.

One thing which I am missing here is what is the recovery checklist?
Mistakes do happen, how can they be efficiently addressed/resolved?

Regards,

-Sergey-
--------------------------------------------------------------------
Sergey Sharybin - sergey at blender.org - www.blender.org
Principal Software Engineer, Blender
Buikslotermeerplein 161, 1025 ET Amsterdam, the Netherlands


On Mon, Nov 16, 2020 at 5:58 PM Brecht Van Lommel via Bf-committers <
bf-committers at blender.org> wrote:

> The difference is between:
> * Providing active support for a processor architecture
> * Rejecting or fixing code that only builds on a specific processor
> architecture
>
> Developers should not write code which e.g. relies on pointers being 64
> bit, integers being little-endian, or adding an x86_64 intrinsic call
> without the appropriate #ifdefs. That's not something you should wait on
> the community to fix. It's a bug in your code, like a null pointer
> dereference or invalid memory access.
>
>
> On Mon, Nov 16, 2020 at 4:55 PM Ray Molenkamp via Bf-committers <
> bf-committers at blender.org> wrote:
>
> > I've always understood our position to be
> >
> > - We do not plan to break or remove 32 bit support.
> > - Given we don't CI on 32 bit anymore, breakage can sometimes happen
> > without us knowing.
> > - If external parties supply patches to fix such breakage and they pass
> > code review, we merge them. Even if they are for platforms we ourselves
> do
> > not ship. D2860 (haiku OS) is a nice example there.
> >
> > I'm not sure if that is the official position, but that's my current
> > understanding of it.
> >
> > --Ray
> >
> > On 2020-11-16 8:36 a.m., Sybren A. Stüvel via Bf-committers wrote:
> > > Hello list,
> > >
> > > Blender 2.80 was the last version of Blender for which 32-bit builds
> > > were officially supported. This was announced by Brecht in [1].
> > > That announcement was a bit unclear to me, which I let pass because it
> > > wasn't that relevant for my position back then. However, now that I'm
> > > the Linux platform maintainer, I wouldn't mind if the situation was
> > > clarified.
> > >
> > > In that announcement, Brecht writes:
> > >> Blender 2.80 was the last release where we officially support 32 bit
> > Windows and Linux builds. [...]
> > >> We will continue to support it to the level that we do for example
> ARM.
> > That is we keep the Blender code working independent of the processor
> > architecture, particularly for Linux packages. But we don't actively test
> > them or release our own builds.
> > > This sounds like an impossibility to me: the promise that we keep
> > > things working, but without building, or testing. Apparently there is
> > > also a distinction between "official support" and "support to some
> > > level".
> > >
> > > The Blender requirements page [2] does list 64-bit as a requirement.
> > > But, there is no "last version that supported 32-bit" in the "Previous
> > > Versions" section of that page. Also there is no mention of dropping
> > > official support for 32-bit architectures in the 2.81 release notes
> > > [3].
> > >
> > > I found out about this unclear situation when looking at a patch that
> > > ought to fix an issue on 32-bit platforms [4]. In the discussion on
> > > that patch, Brecht writes:
> > >> When writing or reviewing code, you ensure that there is always a
> > processor architecture independent code path. And if you get a report and
> > it turns out such a code path is missing or broken, you fix it. It's the
> > same for x86, mips, sparc, etc.
> > > This looks like a statement that these platforms are still supported.
> > >
> > > Personally I would summarize the above as:
> > > - Blender Foundation does not provide buildbots for 32-bit platforms.
> > > - Developers have to ensure these platforms keep working.
> > > - Testing such fixes is unnecessary.
> > >
> > > I think I'm misunderstanding the situation here, and I wouldn't mind
> > > if this was clarified.
> > >
> > > Sybren
> > >
> > > [1]:
> >
> https://lists.blender.org/pipermail/bf-committers/2019-August/050124.html
> > > [2]: https://www.blender.org/download/requirements/
> > > [3]: https://wiki.blender.org/wiki/Reference/Release_Notes/2.81
> > > [4]: https://developer.blender.org/D9577
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