vibe.d 0.7.33 maintenance release

[Sönke Ludwig]

Am 18.05.2018 um 16:00 schrieb Seb:
> On Friday, 18 May 2018 at 13:46:45 UTC, Márcio Martins wrote:
>> On Wednesday, 16 May 2018 at 08:48:15 UTC, Sönke Ludwig wrote:
>>> Being the final public release on the 0.7.x branch, this version on 
>>> DMD 2.068.2 up to DMD 2.080.0 and LDC 1.9.0. It includes some major 
>>> fixes and improvements backported from the 0.8.x branch. Since this 
>>> marks the last 0.7.x release, all code depending on it should now be 
>>> upgraded to 0.8.3 or later.
>>>
>>> Change log:
>>> <http://vibed.org/blog/posts/vibe-release-0.7.33>
>>>
>>> DUB package:
>>> <https://code.dlang.org/packages/vibe-d/0.7.32>
>>
>> Comparing with 0.7.x, how production-ready would you say the 0.8.x 
>> branch is, and what are the main advantages?
>>
>> Thank you for the awesome work!
> 
> I think I can try to answer this for you.
> 0.8.x has been in production use for almost a year now.
> 
> There have been tons of improvements in the API, performance and new 
> functionality, so it's hard to boil down individual items. The full 
> changelog is here:
> 
> http://vibed.org/blog/posts/vibe-release-0.8.0
> 
> The biggest change is probably that 0.8 now uses subpackages and the new 
> vibe-core package is available for opt-in usage.
> Vibe-core is a pure D replacement of the old libevent-based 
> event-handling (that's simplified because the actual logic is done by 
> eventcore and it contains more functionality too).
> Anyhow, there have been a few regressions when vibe.d switched to use 
> the new vibe-core in 0.8.3, but funnily it also fixed quite a few 
> existing issues with libevent.
> So tl;dr: it's safe to upgrade and if you run into any immediate 
> troubles, stick to the old libevent for one or two releases (it can be 
> selected via the vibe-core subconfiguration).

To add to this, when using the libevent driver, the major changes are 
mainly just type system related (`@safe` and `nothrow` support), so in 
terms of functionality and risk of regressions it is probably safe to 
say that it is not much different than a 0.7.x point release.

The new vibe-core module also runs fine in most contexts, but seems to 
amplify a GC memory consumption/leak issue (visible in the DUB registry) 
and there is still an unresolved report of performance issues in the 
HTTP client (which I couldn't reproduce so far). So this should still be 
used with care in production - on the other hand, any controlled 
real-world exposure is of course highly desirable in order to pinpoint 
any remaining issues.

As Sebastian pointed out, it does fix quite a number of existing, but 
rarely encountered, issues that exist in the libevent implementation, 
because it uses a much more robust approach to fiber scheduling. It also 
has the potential for much better performance, although that is 
currently still nullified by some implementation choices in the HTTP 
server code.

Another big improvement is the diet-ng library, which uses less 
compile-time memory and is a lot more flexible than the old 
`vibe.textfilter.diet` module.