[llvm-dev] [3.9 Release] Release plan and call for testers

[Rafael Espíndola via llvm-dev]

On 13 June 2016 at 10:11, Tom Stellard <tom at stellard.net> wrote:
> On Mon, Jun 13, 2016 at 09:14:43AM -0400, Rafael Espíndola wrote:
>> > The 4.1 release gives us the opportunity to drop support for 3.x
>> > bitcode formats, so  I don't think we should move to 4.x until we have
>> > older bitcode features that we really want to drop.  There should
>> > probably be a separate discussion thread about this.
>>
>> It give the opportunity, not the obligation. Given that I think it is
>> an independent issue and would suggest we just keep the revisions
>> simple and switch trunk to 4.0.
>>
>
> Hi Rafael,
>
> The main issue I see with automatically moving to 4.0, is that if a year
> from now we decide we want to drop a bitcode feature, we can't really do
> it unless we bump the major version again to 5.0.  If we continue on
> with 3.x, then we still have the flexibility to drop bitcode features
> when we decide it's necessary.

OK, I guess that is where your reading of the version differ.

I read that we promise that 4.0 will read all of 3.X, but make no
further promises. That means that in 4.1 we *can* drop support for all
3.x, keep support for everything or something in the middle. But that
is also true for 4.2. So for example it would be valid that

* 4.0 reads all of 3.x
* 4.1 reads >= 3.1
* 4.2 reads >= 3.3

Cheers,
Rafael