On Tue, 24 Jul 2012 01:50:02 -0700, Don Clugston <[email protected]> wrote:

On 16/07/12 09:51, Adam Wilson wrote:
As a result of the D Versioning thread, we have decided to create a new
organization on Github called dlang-stable. This organization will be
responsible for maintaining stable releases of DMD, DRuntime, and Phobos.

So what is a stable release?
A stable release is a complete build of DMD, DRuntime, and Phobos that
ONLY includes the latest bug-fixes and non-breaking enhancements to
existing features. It will not include, new features, breaking
enhancements, and any other code that the core development team may be
working on.

I'm not actually sure what this means. I fear that it may be motivated by an inaccurate assessment of the current situation.

The existing instability comes almost entirely from Phobos, not from the compiler. Historically there have been very few instances where you might want to choose an older compiler in preference to the latest release.

As I've said before, the one time when a language change caused *massive* instability was in the attempt to move AAs from language to library -- even though that wasn't even supposed to affect existing code in any way. The other thing that typically causes regressions is fixes to forward-reference bugs.

Historically, addition of new language features has NOT caused instability. What has been true is that features have been added to the compiler before they were really usable, but they have not broken existing code. Fairly obviously the 64 bit compiler was quite buggy when initially released. But even that massive change wasn't much more buggy than the library AAs! So I am not sure that you can correctly guess where instability will come from.

In summary -- I would not expect your stable DMD to be very different from the normal DMD. Phobos is where the instability issue is.

There are three issues we are trying to address:

The first and largest issue is the long and variable periods between DMD releases. By the end of the 2.060 Beta period there will have been at least 3.5 months since 2.059. And while for the people who can use Git HEAD this may not be a problem, there are MANY who, for whatever reason, must use the released versions. For them the 314 resolved issues and dozens of regressions fixed are a tantalizingly out of reach.

The second issue is the root of the first. Much of the delay was caused by Walter starting to work on COFF. Which brings up the second point of contention in the community, a significant number of bugs are typically introduced when this new work is introduced precisely because it's not ready, and the effort required to make it stable would significantly delay the release, which loops back to the first problem of release cadence. Yes, D is more stable than ever, but we keep breaking it to push bugfix builds because the community starts to get restless without bugfixes. Which is the whole reason this stable project got started.

The third is the result of the first two. The slow release cadence combined with the requirement to push new features along side bug-fixes is seriously holding back the growth of the D community. There is a feeling out here that D is lurching unsteadily forward when it should be smoothly accelerating and most of this feeling is rooted in the prior two causes. This has a very corrosive effect on the community and particularly their willingness to contribute.

The goal of dlang-stable is to provide the primary development team (you!) with the ability to release whenever you feel a new feature or enhancement is stable enough to be released WITHOUT having to worry about the ever growing number of bugfixes that are backlogged in with the new features. We are trying to reduce the bugfix pressure so that you can focus on delivering high-quality code when it's ready.

The community WANTS these new features, but we CAN'T wait 3.5 months (or more!) for the bugfixes that are baked in with them. We have to provide BOTH.

That is dlang-stable.

--
Adam Wilson
IRC: LightBender
Project Coordinator
The Horizon Project
http://www.thehorizonproject.org/

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