Why no stable LTS releases?

[Iain Buclaw]

On Monday, 14 June 2021 at 12:13:40 UTC, Ola Fosheim Grøstad 
wrote:
> On Monday, 14 June 2021 at 09:18:19 UTC, Iain Buclaw wrote:
>> The front-end used by GDC _is_ DMD. :-)
>>
>> You can generally expect any given major release of GCC to 
>> support and backport any fixes to the version of DMD it's 
>> sporting for 3 years.
>
> Sadly, LDC was much easier to compile on Mac than GCC the last 
> time I tried. If this is changed then it makes a lot of sense 
> to view GDC as a stable release if it is stable over a period 
> of 3+ years.
>

The darwin port maintainer and I have been testing various OS X 
versions and hardware combinations.
  - PPC almost passes cleanly save for some unknown deadlock in 
druntime when printing the stack trace of an uncaught exception.
  - Anything older than OS X 10.5 or 10.6 generally won't work.
  - OS X 10.6 through to 10.8 mostly pass, but may require you to 
stub out missing symbols present only in newer versions.
  - OS X 10.9 through to 10.15 pretty much all pass (and the 
[Cirrus CI 
pipelines](https://cirrus-ci.com/task/5207064629739520) I've 
added have been keeping tabs on this).
  - OS X 11 reported tests that started failing again, but having 
checked DMD, and I can safely say that it fails for [all 
compilers](https://issues.dlang.org/show_bug.cgi?id=21919).

> But then you have to be quite picky about which release of DMD 
> you embrace, and not try to follow the latest release because 
> people demand it (before it has proven itself as free of 
> regressions).
>

I think people would prefer to have the latest over 
regression-free.  Having a release branch open for 3 years should 
allow plenty of time for all regressions to be plugged long after 
DMD has moved on to the next major release.

> Another issue is that of libraries an "tutorialish" starting 
> points (like a 2D game app on github that is a startingpoint 
> for writing your own games).
>
> They need a clear set of feature-profiles, so that it is clear 
> whether a compiler upgrade will break or not break an older 
> code base. People seem to complain about this regularly in the 
> forums; they found something interesting on github, try to 
> compile it and get lots of errors.
>
> What is the difference between GDC and LDC? Off the top of my 
> head:
> 1. I assume dcompute
> 2. LLVM intrinsics
>

3. ldc.attributes vs. gcc.attributes.  I've kept it in sync with 
LDC, but GDC has a few more attributes available - mostly 
alternative names though to match GCC equivalents.

> Are there differences between GDC and LDC inline assembly?
>

Yes, there are.  Though LDC does support GDC-style asm nowadays.